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2025-07-24rxrpc: Fix recv-recv race of completed callDavid Howells
[ Upstream commit 962fb1f651c2cf2083e0c3ef53ba69e3b96d3fbc ] If a call receives an event (such as incoming data), the call gets placed on the socket's queue and a thread in recvmsg can be awakened to go and process it. Once the thread has picked up the call off of the queue, further events will cause it to be requeued, and once the socket lock is dropped (recvmsg uses call->user_mutex to allow the socket to be used in parallel), a second thread can come in and its recvmsg can pop the call off the socket queue again. In such a case, the first thread will be receiving stuff from the call and the second thread will be blocked on call->user_mutex. The first thread can, at this point, process both the event that it picked call for and the event that the second thread picked the call for and may see the call terminate - in which case the call will be "released", decoupling the call from the user call ID assigned to it (RXRPC_USER_CALL_ID in the control message). The first thread will return okay, but then the second thread will wake up holding the user_mutex and, if it sees that the call has been released by the first thread, it will BUG thusly: kernel BUG at net/rxrpc/recvmsg.c:474! Fix this by just dequeuing the call and ignoring it if it is seen to be already released. We can't tell userspace about it anyway as the user call ID has become stale. Fixes: 248f219cb8bc ("rxrpc: Rewrite the data and ack handling code") Reported-by: Junvyyang, Tencent Zhuque Lab <zhuque@tencent.com> Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeffrey Altman <jaltman@auristor.com> cc: LePremierHomme <kwqcheii@proton.me> cc: Marc Dionne <marc.dionne@auristor.com> cc: Simon Horman <horms@kernel.org> cc: linux-afs@lists.infradead.org Link: https://patch.msgid.link/20250717074350.3767366-3-dhowells@redhat.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-07-24netfilter: nf_conntrack: fix crash due to removal of uninitialised entryFlorian Westphal
[ Upstream commit 2d72afb340657f03f7261e9243b44457a9228ac7 ] A crash in conntrack was reported while trying to unlink the conntrack entry from the hash bucket list: [exception RIP: __nf_ct_delete_from_lists+172] [..] #7 [ff539b5a2b043aa0] nf_ct_delete at ffffffffc124d421 [nf_conntrack] #8 [ff539b5a2b043ad0] nf_ct_gc_expired at ffffffffc124d999 [nf_conntrack] #9 [ff539b5a2b043ae0] __nf_conntrack_find_get at ffffffffc124efbc [nf_conntrack] [..] The nf_conn struct is marked as allocated from slab but appears to be in a partially initialised state: ct hlist pointer is garbage; looks like the ct hash value (hence crash). ct->status is equal to IPS_CONFIRMED|IPS_DYING, which is expected ct->timeout is 30000 (=30s), which is unexpected. Everything else looks like normal udp conntrack entry. If we ignore ct->status and pretend its 0, the entry matches those that are newly allocated but not yet inserted into the hash: - ct hlist pointers are overloaded and store/cache the raw tuple hash - ct->timeout matches the relative time expected for a new udp flow rather than the absolute 'jiffies' value. If it were not for the presence of IPS_CONFIRMED, __nf_conntrack_find_get() would have skipped the entry. Theory is that we did hit following race: cpu x cpu y cpu z found entry E found entry E E is expired <preemption> nf_ct_delete() return E to rcu slab init_conntrack E is re-inited, ct->status set to 0 reply tuplehash hnnode.pprev stores hash value. cpu y found E right before it was deleted on cpu x. E is now re-inited on cpu z. cpu y was preempted before checking for expiry and/or confirm bit. ->refcnt set to 1 E now owned by skb ->timeout set to 30000 If cpu y were to resume now, it would observe E as expired but would skip E due to missing CONFIRMED bit. nf_conntrack_confirm gets called sets: ct->status |= CONFIRMED This is wrong: E is not yet added to hashtable. cpu y resumes, it observes E as expired but CONFIRMED: <resumes> nf_ct_expired() -> yes (ct->timeout is 30s) confirmed bit set. cpu y will try to delete E from the hashtable: nf_ct_delete() -> set DYING bit __nf_ct_delete_from_lists Even this scenario doesn't guarantee a crash: cpu z still holds the table bucket lock(s) so y blocks: wait for spinlock held by z CONFIRMED is set but there is no guarantee ct will be added to hash: "chaintoolong" or "clash resolution" logic both skip the insert step. reply hnnode.pprev still stores the hash value. unlocks spinlock return NF_DROP <unblocks, then crashes on hlist_nulls_del_rcu pprev> In case CPU z does insert the entry into the hashtable, cpu y will unlink E again right away but no crash occurs. Without 'cpu y' race, 'garbage' hlist is of no consequence: ct refcnt remains at 1, eventually skb will be free'd and E gets destroyed via: nf_conntrack_put -> nf_conntrack_destroy -> nf_ct_destroy. To resolve this, move the IPS_CONFIRMED assignment after the table insertion but before the unlock. Pablo points out that the confirm-bit-store could be reordered to happen before hlist add resp. the timeout fixup, so switch to set_bit and before_atomic memory barrier to prevent this. It doesn't matter if other CPUs can observe a newly inserted entry right before the CONFIRMED bit was set: Such event cannot be distinguished from above "E is the old incarnation" case: the entry will be skipped. Also change nf_ct_should_gc() to first check the confirmed bit. The gc sequence is: 1. Check if entry has expired, if not skip to next entry 2. Obtain a reference to the expired entry. 3. Call nf_ct_should_gc() to double-check step 1. nf_ct_should_gc() is thus called only for entries that already failed an expiry check. After this patch, once the confirmed bit check passes ct->timeout has been altered to reflect the absolute 'best before' date instead of a relative time. Step 3 will therefore not remove the entry. Without this change to nf_ct_should_gc() we could still get this sequence: 1. Check if entry has expired. 2. Obtain a reference. 3. Call nf_ct_should_gc() to double-check step 1: 4 - entry is still observed as expired 5 - meanwhile, ct->timeout is corrected to absolute value on other CPU and confirm bit gets set 6 - confirm bit is seen 7 - valid entry is removed again First do check 6), then 4) so the gc expiry check always picks up either confirmed bit unset (entry gets skipped) or expiry re-check failure for re-inited conntrack objects. This change cannot be backported to releases before 5.19. Without commit 8a75a2c17410 ("netfilter: conntrack: remove unconfirmed list") |= IPS_CONFIRMED line cannot be moved without further changes. Cc: Razvan Cojocaru <rzvncj@gmail.com> Link: https://lore.kernel.org/netfilter-devel/20250627142758.25664-1-fw@strlen.de/ Link: https://lore.kernel.org/netfilter-devel/4239da15-83ff-4ca4-939d-faef283471bb@gmail.com/ Fixes: 1397af5bfd7d ("netfilter: conntrack: remove the percpu dying list") Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-07-24wifi: cfg80211: remove scan request n_channels counted_byJohannes Berg
[ Upstream commit 444020f4bf06fb86805ee7e7ceec0375485fd94d ] This reverts commit e3eac9f32ec0 ("wifi: cfg80211: Annotate struct cfg80211_scan_request with __counted_by"). This really has been a completely failed experiment. There were no actual bugs found, and yet at this point we already have four "fixes" to it, with nothing to show for but code churn, and it never even made the code any safer. In all of the cases that ended up getting "fixed", the structure is also internally inconsistent after the n_channels setting as the channel list isn't actually filled yet. You cannot scan with such a structure, that's just wrong. In mac80211, the struct is also reused multiple times, so initializing it once is no good. Some previous "fixes" (e.g. one in brcm80211) are also just setting n_channels before accessing the array, under the assumption that the code is correct and the array can be accessed, further showing that the whole thing is just pointless when the allocation count and use count are not separate. If we really wanted to fix it, we'd need to separately track the number of channels allocated and the number of channels currently used, but given that no bugs were found despite the numerous syzbot reports, that'd just be a waste of time. Remove the __counted_by() annotation. We really should also remove a number of the n_channels settings that are setting up a structure that's inconsistent, but that can wait. Reported-by: syzbot+e834e757bd9b3d3e1251@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=e834e757bd9b3d3e1251 Fixes: e3eac9f32ec0 ("wifi: cfg80211: Annotate struct cfg80211_scan_request with __counted_by") Link: https://patch.msgid.link/20250714142130.9b0bbb7e1f07.I09112ccde72d445e11348fc2bef68942cb2ffc94@changeid Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-07-17crypto: ecdsa - Harden against integer overflows in DIV_ROUND_UP()Lukas Wunner
commit b16510a530d1e6ab9683f04f8fb34f2e0f538275 upstream. Herbert notes that DIV_ROUND_UP() may overflow unnecessarily if an ecdsa implementation's ->key_size() callback returns an unusually large value. Herbert instead suggests (for a division by 8): X / 8 + !!(X & 7) Based on this formula, introduce a generic DIV_ROUND_UP_POW2() macro and use it in lieu of DIV_ROUND_UP() for ->key_size() return values. Additionally, use the macro in ecc_digits_from_bytes(), whose "nbytes" parameter is a ->key_size() return value in some instances, or a user-specified ASN.1 length in the case of ecdsa_get_signature_rs(). Link: https://lore.kernel.org/r/Z3iElsILmoSu6FuC@gondor.apana.org.au/ Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-07-17netfilter: flowtable: account for Ethernet header in nf_flow_pppoe_proto()Eric Dumazet
[ Upstream commit 18cdb3d982da8976b28d57691eb256ec5688fad2 ] syzbot found a potential access to uninit-value in nf_flow_pppoe_proto() Blamed commit forgot the Ethernet header. BUG: KMSAN: uninit-value in nf_flow_offload_inet_hook+0x7e4/0x940 net/netfilter/nf_flow_table_inet.c:27 nf_flow_offload_inet_hook+0x7e4/0x940 net/netfilter/nf_flow_table_inet.c:27 nf_hook_entry_hookfn include/linux/netfilter.h:157 [inline] nf_hook_slow+0xe1/0x3d0 net/netfilter/core.c:623 nf_hook_ingress include/linux/netfilter_netdev.h:34 [inline] nf_ingress net/core/dev.c:5742 [inline] __netif_receive_skb_core+0x4aff/0x70c0 net/core/dev.c:5837 __netif_receive_skb_one_core net/core/dev.c:5975 [inline] __netif_receive_skb+0xcc/0xac0 net/core/dev.c:6090 netif_receive_skb_internal net/core/dev.c:6176 [inline] netif_receive_skb+0x57/0x630 net/core/dev.c:6235 tun_rx_batched+0x1df/0x980 drivers/net/tun.c:1485 tun_get_user+0x4ee0/0x6b40 drivers/net/tun.c:1938 tun_chr_write_iter+0x3e9/0x5c0 drivers/net/tun.c:1984 new_sync_write fs/read_write.c:593 [inline] vfs_write+0xb4b/0x1580 fs/read_write.c:686 ksys_write fs/read_write.c:738 [inline] __do_sys_write fs/read_write.c:749 [inline] Reported-by: syzbot+bf6ed459397e307c3ad2@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/686bc073.a00a0220.c7b3.0086.GAE@google.com/T/#u Fixes: 87b3593bed18 ("netfilter: flowtable: validate pppoe header") Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Pablo Neira Ayuso <pablo@netfilter.org> Link: https://patch.msgid.link/20250707124517.614489-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-07-17mm: fix the inaccurate memory statistics issue for usersBaolin Wang
commit 82241a83cd15aaaf28200a40ad1a8b480012edaf upstream. On some large machines with a high number of CPUs running a 64K pagesize kernel, we found that the 'RES' field is always 0 displayed by the top command for some processes, which will cause a lot of confusion for users. PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 875525 root 20 0 12480 0 0 R 0.3 0.0 0:00.08 top 1 root 20 0 172800 0 0 S 0.0 0.0 0:04.52 systemd The main reason is that the batch size of the percpu counter is quite large on these machines, caching a significant percpu value, since converting mm's rss stats into percpu_counter by commit f1a7941243c1 ("mm: convert mm's rss stats into percpu_counter"). Intuitively, the batch number should be optimized, but on some paths, performance may take precedence over statistical accuracy. Therefore, introducing a new interface to add the percpu statistical count and display it to users, which can remove the confusion. In addition, this change is not expected to be on a performance-critical path, so the modification should be acceptable. In addition, the 'mm->rss_stat' is updated by using add_mm_counter() and dec/inc_mm_counter(), which are all wrappers around percpu_counter_add_batch(). In percpu_counter_add_batch(), there is percpu batch caching to avoid 'fbc->lock' contention. This patch changes task_mem() and task_statm() to get the accurate mm counters under the 'fbc->lock', but this should not exacerbate kernel 'mm->rss_stat' lock contention due to the percpu batch caching of the mm counters. The following test also confirm the theoretical analysis. I run the stress-ng that stresses anon page faults in 32 threads on my 32 cores machine, while simultaneously running a script that starts 32 threads to busy-loop pread each stress-ng thread's /proc/pid/status interface. From the following data, I did not observe any obvious impact of this patch on the stress-ng tests. w/o patch: stress-ng: info: [6848] 4,399,219,085,152 CPU Cycles 67.327 B/sec stress-ng: info: [6848] 1,616,524,844,832 Instructions 24.740 B/sec (0.367 instr. per cycle) stress-ng: info: [6848] 39,529,792 Page Faults Total 0.605 M/sec stress-ng: info: [6848] 39,529,792 Page Faults Minor 0.605 M/sec w/patch: stress-ng: info: [2485] 4,462,440,381,856 CPU Cycles 68.382 B/sec stress-ng: info: [2485] 1,615,101,503,296 Instructions 24.750 B/sec (0.362 instr. per cycle) stress-ng: info: [2485] 39,439,232 Page Faults Total 0.604 M/sec stress-ng: info: [2485] 39,439,232 Page Faults Minor 0.604 M/sec On comparing a very simple app which just allocates & touches some memory against v6.1 (which doesn't have f1a7941243c1) and latest Linus tree (4c06e63b9203) I can see that on latest Linus tree the values for VmRSS, RssAnon and RssFile from /proc/self/status are all zeroes while they do report values on v6.1 and a Linus tree with this patch. Link: https://lkml.kernel.org/r/f4586b17f66f97c174f7fd1f8647374fdb53de1c.1749119050.git.baolin.wang@linux.alibaba.com Fixes: f1a7941243c1 ("mm: convert mm's rss stats into percpu_counter") Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> Reviewed-by: Aboorva Devarajan <aboorvad@linux.ibm.com> Tested-by: Aboorva Devarajan <aboorvad@linux.ibm.com> Tested-by Donet Tom <donettom@linux.ibm.com> Acked-by: Shakeel Butt <shakeel.butt@linux.dev> Acked-by: SeongJae Park <sj@kernel.org> Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: David Hildenbrand <david@redhat.com> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-07-17drm/framebuffer: Acquire internal references on GEM handlesThomas Zimmermann
commit f6bfc9afc7510cb5e6fbe0a17c507917b0120280 upstream. Acquire GEM handles in drm_framebuffer_init() and release them in the corresponding drm_framebuffer_cleanup(). Ties the handle's lifetime to the framebuffer. Not all GEM buffer objects have GEM handles. If not set, no refcounting takes place. This is the case for some fbdev emulation. This is not a problem as these GEM objects do not use dma-bufs and drivers will not release them while fbdev emulation is running. Framebuffer flags keep a bit per color plane of which the framebuffer holds a GEM handle reference. As all drivers use drm_framebuffer_init(), they will now all hold dma-buf references as fixed in commit 5307dce878d4 ("drm/gem: Acquire references on GEM handles for framebuffers"). In the GEM framebuffer helpers, restore the original ref counting on buffer objects. As the helpers for handle refcounting are now no longer called from outside the DRM core, unexport the symbols. v3: - don't mix internal flags with mode flags (Christian) v2: - track framebuffer handle refs by flag - drop gma500 cleanup (Christian) Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> Fixes: 5307dce878d4 ("drm/gem: Acquire references on GEM handles for framebuffers") Reported-by: Bert Karwatzki <spasswolf@web.de> Closes: https://lore.kernel.org/dri-devel/20250703115915.3096-1-spasswolf@web.de/ Tested-by: Bert Karwatzki <spasswolf@web.de> Tested-by: Mario Limonciello <superm1@kernel.org> Tested-by: Borislav Petkov (AMD) <bp@alien8.de> Cc: Thomas Zimmermann <tzimmermann@suse.de> Cc: Anusha Srivatsa <asrivats@redhat.com> Cc: Christian König <christian.koenig@amd.com> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: Maxime Ripard <mripard@kernel.org> Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: "Christian König" <christian.koenig@amd.com> Cc: linux-media@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Cc: linaro-mm-sig@lists.linaro.org Cc: <stable@vger.kernel.org> Reviewed-by: Christian König <christian.koenig@amd.com> Link: https://lore.kernel.org/r/20250707131224.249496-1-tzimmermann@suse.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-07-17drm/gem: Fix race in drm_gem_handle_create_tail()Simona Vetter
commit bd46cece51a36ef088f22ef0416ac13b0a46d5b0 upstream. Object creation is a careful dance where we must guarantee that the object is fully constructed before it is visible to other threads, and GEM buffer objects are no difference. Final publishing happens by calling drm_gem_handle_create(). After that the only allowed thing to do is call drm_gem_object_put() because a concurrent call to the GEM_CLOSE ioctl with a correctly guessed id (which is trivial since we have a linear allocator) can already tear down the object again. Luckily most drivers get this right, the very few exceptions I've pinged the relevant maintainers for. Unfortunately we also need drm_gem_handle_create() when creating additional handles for an already existing object (e.g. GETFB ioctl or the various bo import ioctl), and hence we cannot have a drm_gem_handle_create_and_put() as the only exported function to stop these issues from happening. Now unfortunately the implementation of drm_gem_handle_create() isn't living up to standards: It does correctly finishe object initialization at the global level, and hence is safe against a concurrent tear down. But it also sets up the file-private aspects of the handle, and that part goes wrong: We fully register the object in the drm_file.object_idr before calling drm_vma_node_allow() or obj->funcs->open, which opens up races against concurrent removal of that handle in drm_gem_handle_delete(). Fix this with the usual two-stage approach of first reserving the handle id, and then only registering the object after we've completed the file-private setup. Jacek reported this with a testcase of concurrently calling GEM_CLOSE on a freshly-created object (which also destroys the object), but it should be possible to hit this with just additional handles created through import or GETFB without completed destroying the underlying object with the concurrent GEM_CLOSE ioctl calls. Note that the close-side of this race was fixed in f6cd7daecff5 ("drm: Release driver references to handle before making it available again"), which means a cool 9 years have passed until someone noticed that we need to make this symmetry or there's still gaps left :-/ Without the 2-stage close approach we'd still have a race, therefore that's an integral part of this bugfix. More importantly, this means we can have NULL pointers behind allocated id in our drm_file.object_idr. We need to check for that now: - drm_gem_handle_delete() checks for ERR_OR_NULL already - drm_gem.c:object_lookup() also chekcs for NULL - drm_gem_release() should never be called if there's another thread still existing that could call into an IOCTL that creates a new handle, so cannot race. For paranoia I added a NULL check to drm_gem_object_release_handle() though. - most drivers (etnaviv, i915, msm) are find because they use idr_find(), which maps both ENOENT and NULL to NULL. - drivers using idr_for_each_entry() should also be fine, because idr_get_next does filter out NULL entries and continues the iteration. - The same holds for drm_show_memory_stats(). v2: Use drm_WARN_ON (Thomas) Reported-by: Jacek Lawrynowicz <jacek.lawrynowicz@linux.intel.com> Tested-by: Jacek Lawrynowicz <jacek.lawrynowicz@linux.intel.com> Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de> Cc: stable@vger.kernel.org Cc: Jacek Lawrynowicz <jacek.lawrynowicz@linux.intel.com> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: Maxime Ripard <mripard@kernel.org> Cc: Thomas Zimmermann <tzimmermann@suse.de> Cc: David Airlie <airlied@gmail.com> Cc: Simona Vetter <simona@ffwll.ch> Signed-off-by: Simona Vetter <simona.vetter@intel.com> Signed-off-by: Simona Vetter <simona.vetter@ffwll.ch> Link: https://patchwork.freedesktop.org/patch/msgid/20250707151814.603897-1-simona.vetter@ffwll.ch Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-07-17drm/sched: Increment job count before swapping tail spsc queueMatthew Brost
commit 8af39ec5cf2be522c8eb43a3d8005ed59e4daaee upstream. A small race exists between spsc_queue_push and the run-job worker, in which spsc_queue_push may return not-first while the run-job worker has already idled due to the job count being zero. If this race occurs, job scheduling stops, leading to hangs while waiting on the job’s DMA fences. Seal this race by incrementing the job count before appending to the SPSC queue. This race was observed on a drm-tip 6.16-rc1 build with the Xe driver in an SVM test case. Fixes: 1b1f42d8fde4 ("drm: move amd_gpu_scheduler into common location") Fixes: 27105db6c63a ("drm/amdgpu: Add SPSC queue to scheduler.") Cc: stable@vger.kernel.org Signed-off-by: Matthew Brost <matthew.brost@intel.com> Reviewed-by: Jonathan Cavitt <jonathan.cavitt@intel.com> Link: https://lore.kernel.org/r/20250613212013.719312-1-matthew.brost@intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-07-17vsock: fix `vsock_proto` declarationStefano Garzarella
[ Upstream commit 1e3b66e326015f77bc4b36976bebeedc2ac0f588 ] From commit 634f1a7110b4 ("vsock: support sockmap"), `struct proto vsock_proto`, defined in af_vsock.c, is not static anymore, since it's used by vsock_bpf.c. If CONFIG_BPF_SYSCALL is not defined, `make C=2` will print a warning: $ make O=build C=2 W=1 net/vmw_vsock/ ... CC [M] net/vmw_vsock/af_vsock.o CHECK ../net/vmw_vsock/af_vsock.c ../net/vmw_vsock/af_vsock.c:123:14: warning: symbol 'vsock_proto' was not declared. Should it be static? Declare `vsock_proto` regardless of CONFIG_BPF_SYSCALL, since it's defined in af_vsock.c, which is built regardless of CONFIG_BPF_SYSCALL. Fixes: 634f1a7110b4 ("vsock: support sockmap") Signed-off-by: Stefano Garzarella <sgarzare@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Link: https://patch.msgid.link/20250703112329.28365-1-sgarzare@redhat.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-07-10x86/bugs: Add a Transient Scheduler Attacks mitigationBorislav Petkov (AMD)
Commit d8010d4ba43e9f790925375a7de100604a5e2dba upstream. Add the required features detection glue to bugs.c et all in order to support the TSA mitigation. Co-developed-by: Kim Phillips <kim.phillips@amd.com> Signed-off-by: Kim Phillips <kim.phillips@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-07-10fs: export anon_inode_make_secure_inode() and fix secretmem LSM bypassShivank Garg
[ Upstream commit cbe4134ea4bc493239786220bd69cb8a13493190 ] Export anon_inode_make_secure_inode() to allow KVM guest_memfd to create anonymous inodes with proper security context. This replaces the current pattern of calling alloc_anon_inode() followed by inode_init_security_anon() for creating security context manually. This change also fixes a security regression in secretmem where the S_PRIVATE flag was not cleared after alloc_anon_inode(), causing LSM/SELinux checks to be bypassed for secretmem file descriptors. As guest_memfd currently resides in the KVM module, we need to export this symbol for use outside the core kernel. In the future, guest_memfd might be moved to core-mm, at which point the symbols no longer would have to be exported. When/if that happens is still unclear. Fixes: 2bfe15c52612 ("mm: create security context for memfd_secret inodes") Suggested-by: David Hildenbrand <david@redhat.com> Suggested-by: Mike Rapoport <rppt@kernel.org> Signed-off-by: Shivank Garg <shivankg@amd.com> Link: https://lore.kernel.org/20250620070328.803704-3-shivankg@amd.com Acked-by: "Mike Rapoport (Microsoft)" <rppt@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-07-10module: Provide EXPORT_SYMBOL_GPL_FOR_MODULES() helperPeter Zijlstra
[ Upstream commit 707f853d7fa3ce323a6875487890c213e34d81a0 ] Helper macro to more easily limit the export of a symbol to a given list of modules. Eg: EXPORT_SYMBOL_GPL_FOR_MODULES(preempt_notifier_inc, "kvm"); will limit the use of said function to kvm.ko, any other module trying to use this symbol will refure to load (and get modpost build failures). Requested-by: Masahiro Yamada <masahiroy@kernel.org> Requested-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Reviewed-by: Petr Pavlu <petr.pavlu@suse.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Stable-dep-of: cbe4134ea4bc ("fs: export anon_inode_make_secure_inode() and fix secretmem LSM bypass") Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-07-10ata: libata-acpi: Do not assume 40 wire cable if no devices are enabledTasos Sahanidis
[ Upstream commit 33877220b8641b4cde474a4229ea92c0e3637883 ] On at least an ASRock 990FX Extreme 4 with a VIA VT6330, the devices have not yet been enabled by the first time ata_acpi_cbl_80wire() is called. This means that the ata_for_each_dev loop is never entered, and a 40 wire cable is assumed. The VIA controller on this board does not report the cable in the PCI config space, thus having to fall back to ACPI even though no SATA bridge is present. The _GTM values are correctly reported by the firmware through ACPI, which has already set up faster transfer modes, but due to the above the controller is forced down to a maximum of UDMA/33. Resolve this by modifying ata_acpi_cbl_80wire() to directly return the cable type. First, an unknown cable is assumed which preserves the mode set by the firmware, and then on subsequent calls when the devices have been enabled, an 80 wire cable is correctly detected. Since the function now directly returns the cable type, it is renamed to ata_acpi_cbl_pata_type(). Signed-off-by: Tasos Sahanidis <tasos@tasossah.com> Link: https://lore.kernel.org/r/20250519085945.1399466-1-tasos@tasossah.com Signed-off-by: Niklas Cassel <cassel@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-07-10scsi: ufs: core: Add OPP support for scaling clocks and regulatorsManivannan Sadhasivam
[ Upstream commit 930bd77ebe3dc23b18aa49e55e6a515d5663d67a ] UFS core is only scaling the clocks during devfreq scaling and initialization. But for an optimum power saving, regulators should also be scaled along with the clocks. So let's use the OPP framework which supports scaling clocks, regulators, and performance state using OPP table defined in devicetree. For accomodating the OPP support, the existing APIs (ufshcd_scale_clks, ufshcd_is_devfreq_scaling_required and ufshcd_devfreq_scale) are modified to accept "freq" as an argument which in turn used by the OPP helpers. The OPP support is added along with the old freq-table based clock scaling so that the existing platforms work as expected. Co-developed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> Link: https://lore.kernel.org/r/20231012172129.65172-3-manivannan.sadhasivam@linaro.org Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Stable-dep-of: 2e083cd80229 ("scsi: ufs: core: Fix clk scaling to be conditional in reset and restore") Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-07-10f2fs: add tracepoint for f2fs_vm_page_mkwrite()Chao Yu
[ Upstream commit 87f3afd366f7c668be0269efda8a89741a3ea6b3 ] This patch adds to support tracepoint for f2fs_vm_page_mkwrite(), meanwhile it prints more details for trace_f2fs_filemap_fault(). Signed-off-by: Chao Yu <chao@kernel.org> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org> Stable-dep-of: ba8dac350faf ("f2fs: fix to zero post-eof page") Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-07-10Bluetooth: hci_core: Fix use-after-free in vhci_flush()Kuniyuki Iwashima
[ Upstream commit 1d6123102e9fbedc8d25bf4731da6d513173e49e ] syzbot reported use-after-free in vhci_flush() without repro. [0] From the splat, a thread close()d a vhci file descriptor while its device was being used by iotcl() on another thread. Once the last fd refcnt is released, vhci_release() calls hci_unregister_dev(), hci_free_dev(), and kfree() for struct vhci_data, which is set to hci_dev->dev->driver_data. The problem is that there is no synchronisation after unlinking hdev from hci_dev_list in hci_unregister_dev(). There might be another thread still accessing the hdev which was fetched before the unlink operation. We can use SRCU for such synchronisation. Let's run hci_dev_reset() under SRCU and wait for its completion in hci_unregister_dev(). Another option would be to restore hci_dev->destruct(), which was removed in commit 587ae086f6e4 ("Bluetooth: Remove unused hci-destruct cb"). However, this would not be a good solution, as we should not run hci_unregister_dev() while there are in-flight ioctl() requests, which could lead to another data-race KCSAN splat. Note that other drivers seem to have the same problem, for exmaple, virtbt_remove(). [0]: BUG: KASAN: slab-use-after-free in skb_queue_empty_lockless include/linux/skbuff.h:1891 [inline] BUG: KASAN: slab-use-after-free in skb_queue_purge_reason+0x99/0x360 net/core/skbuff.c:3937 Read of size 8 at addr ffff88807cb8d858 by task syz.1.219/6718 CPU: 1 UID: 0 PID: 6718 Comm: syz.1.219 Not tainted 6.16.0-rc1-syzkaller-00196-g08207f42d3ff #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Call Trace: <TASK> dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:408 [inline] print_report+0xd2/0x2b0 mm/kasan/report.c:521 kasan_report+0x118/0x150 mm/kasan/report.c:634 skb_queue_empty_lockless include/linux/skbuff.h:1891 [inline] skb_queue_purge_reason+0x99/0x360 net/core/skbuff.c:3937 skb_queue_purge include/linux/skbuff.h:3368 [inline] vhci_flush+0x44/0x50 drivers/bluetooth/hci_vhci.c:69 hci_dev_do_reset net/bluetooth/hci_core.c:552 [inline] hci_dev_reset+0x420/0x5c0 net/bluetooth/hci_core.c:592 sock_do_ioctl+0xd9/0x300 net/socket.c:1190 sock_ioctl+0x576/0x790 net/socket.c:1311 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:907 [inline] __se_sys_ioctl+0xf9/0x170 fs/ioctl.c:893 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fcf5b98e929 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fcf5c7b9038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fcf5bbb6160 RCX: 00007fcf5b98e929 RDX: 0000000000000000 RSI: 00000000400448cb RDI: 0000000000000009 RBP: 00007fcf5ba10b39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fcf5bbb6160 R15: 00007ffd6353d528 </TASK> Allocated by task 6535: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:377 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:394 kasan_kmalloc include/linux/kasan.h:260 [inline] __kmalloc_cache_noprof+0x230/0x3d0 mm/slub.c:4359 kmalloc_noprof include/linux/slab.h:905 [inline] kzalloc_noprof include/linux/slab.h:1039 [inline] vhci_open+0x57/0x360 drivers/bluetooth/hci_vhci.c:635 misc_open+0x2bc/0x330 drivers/char/misc.c:161 chrdev_open+0x4c9/0x5e0 fs/char_dev.c:414 do_dentry_open+0xdf0/0x1970 fs/open.c:964 vfs_open+0x3b/0x340 fs/open.c:1094 do_open fs/namei.c:3887 [inline] path_openat+0x2ee5/0x3830 fs/namei.c:4046 do_filp_open+0x1fa/0x410 fs/namei.c:4073 do_sys_openat2+0x121/0x1c0 fs/open.c:1437 do_sys_open fs/open.c:1452 [inline] __do_sys_openat fs/open.c:1468 [inline] __se_sys_openat fs/open.c:1463 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1463 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 6535: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:247 [inline] __kasan_slab_free+0x62/0x70 mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2381 [inline] slab_free mm/slub.c:4643 [inline] kfree+0x18e/0x440 mm/slub.c:4842 vhci_release+0xbc/0xd0 drivers/bluetooth/hci_vhci.c:671 __fput+0x44c/0xa70 fs/file_table.c:465 task_work_run+0x1d1/0x260 kernel/task_work.c:227 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x6ad/0x22e0 kernel/exit.c:955 do_group_exit+0x21c/0x2d0 kernel/exit.c:1104 __do_sys_exit_group kernel/exit.c:1115 [inline] __se_sys_exit_group kernel/exit.c:1113 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1113 x64_sys_call+0x21ba/0x21c0 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88807cb8d800 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 88 bytes inside of freed 1024-byte region [ffff88807cb8d800, ffff88807cb8dc00) Fixes: bf18c7118cf8 ("Bluetooth: vhci: Free driver_data on file release") Reported-by: syzbot+2faa4825e556199361f9@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=f62d64848fc4c7c30cd6 Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com> Acked-by: Paul Menzel <pmenzel@molgen.mpg.de> Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-07-10usb: typec: altmodes/displayport: do not index invalid pin_assignmentsRD Babiera
commit af4db5a35a4ef7a68046883bfd12468007db38f1 upstream. A poorly implemented DisplayPort Alt Mode port partner can indicate that its pin assignment capabilities are greater than the maximum value, DP_PIN_ASSIGN_F. In this case, calls to pin_assignment_show will cause a BRK exception due to an out of bounds array access. Prevent for loop in pin_assignment_show from accessing invalid values in pin_assignments by adding DP_PIN_ASSIGN_MAX value in typec_dp.h and using i < DP_PIN_ASSIGN_MAX as a loop condition. Fixes: 0e3bb7d6894d ("usb: typec: Add driver for DisplayPort alternate mode") Cc: stable <stable@kernel.org> Signed-off-by: RD Babiera <rdbabiera@google.com> Reviewed-by: Badhri Jagan Sridharan <badhri@google.com> Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> Link: https://lore.kernel.org/r/20250618224943.3263103-2-rdbabiera@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-07-06Revert "ipv6: save dontfrag in cork"Brett A C Sheffield (Librecast)
This reverts commit 8ebf2709fe4dcd0a1b7b95bf61e529ddcd3cdf51 which is commit a18dfa9925b9ef6107ea3aa5814ca3c704d34a8a upstream. A regression was introduced when backporting this to the stable kernels without applying previous commits in this series. When sending IPv6 UDP packets larger than MTU, EMSGSIZE was returned instead of fragmenting the packets as expected. As there is no compelling reason for this commit to be present in the stable kernels it should be reverted. Signed-off-by: Brett A C Sheffield <bacs@librecast.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-07-06vsock/uapi: fix linux/vm_sockets.h userspace compilation errorsStefano Garzarella
[ Upstream commit 22bbc1dcd0d6785fb390c41f0dd5b5e218d23bdd ] If a userspace application just include <linux/vm_sockets.h> will fail to build with the following errors: /usr/include/linux/vm_sockets.h:182:39: error: invalid application of ‘sizeof’ to incomplete type ‘struct sockaddr’ 182 | unsigned char svm_zero[sizeof(struct sockaddr) - | ^~~~~~ /usr/include/linux/vm_sockets.h:183:39: error: ‘sa_family_t’ undeclared here (not in a function) 183 | sizeof(sa_family_t) - | Include <sys/socket.h> for userspace (guarded by ifndef __KERNEL__) where `struct sockaddr` and `sa_family_t` are defined. We already do something similar in <linux/mptcp.h> and <linux/if.h>. Fixes: d021c344051a ("VSOCK: Introduce VM Sockets") Reported-by: Daan De Meyer <daan.j.demeyer@gmail.com> Signed-off-by: Stefano Garzarella <sgarzare@redhat.com> Link: https://patch.msgid.link/20250623100053.40979-1-sgarzare@redhat.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-07-06tty: vt: make consw::con_switch() return a boolJiri Slaby (SUSE)
[ Upstream commit 8d5cc8eed738e3202379722295c626cba0849785 ] The non-zero (true) return value from consw::con_switch() means a redraw is needed. So make this return type a bool explicitly instead of int. The latter might imply that -Eerrors are expected. They are not. And document the hook. Signed-off-by: "Jiri Slaby (SUSE)" <jirislaby@kernel.org> Cc: Helge Deller <deller@gmx.de> Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: linux-fbdev@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Cc: linux-parisc@vger.kernel.org Tested-by: Helge Deller <deller@gmx.de> # parisc STI console Link: https://lore.kernel.org/r/20240122110401.7289-31-jirislaby@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Stable-dep-of: 03bcbbb3995b ("dummycon: Trigger redraw when switching consoles with deferred takeover") Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-07-06tty: vt: sanitize arguments of consw::con_clear()Jiri Slaby (SUSE)
[ Upstream commit 559f01a0ee6d924c6fec3eaf6a5b078b15e71070 ] In consw::con_clear(): * Height is always 1, so drop it. * Offsets and width are always unsigned values, so re-type them as such. This needs a new __fbcon_clear() in the fbcon code to still handle height which might not be 1 when called internally. Note that tests for negative count/width are left in place -- they are taken care of in the next patches. And document the hook. Signed-off-by: "Jiri Slaby (SUSE)" <jirislaby@kernel.org> Cc: Helge Deller <deller@gmx.de> Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: linux-fbdev@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Cc: linux-parisc@vger.kernel.org Tested-by: Helge Deller <deller@gmx.de> # parisc STI console Link: https://lore.kernel.org/r/20240122110401.7289-22-jirislaby@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Stable-dep-of: 03bcbbb3995b ("dummycon: Trigger redraw when switching consoles with deferred takeover") Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-07-06tty: vt: make init parameter of consw::con_init() a boolJiri Slaby (SUSE)
[ Upstream commit dae3e6b6180f1a2394b984c596d39ed2c57d25fe ] The 'init' parameter of consw::con_init() is true for the first call of the hook on a particular console. So make the parameter a bool. And document the hook. Signed-off-by: "Jiri Slaby (SUSE)" <jirislaby@kernel.org> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Cc: Helge Deller <deller@gmx.de> Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: linux-fbdev@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Cc: linux-parisc@vger.kernel.org Tested-by: Helge Deller <deller@gmx.de> # parisc STI console Link: https://lore.kernel.org/r/20240122110401.7289-21-jirislaby@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Stable-dep-of: 03bcbbb3995b ("dummycon: Trigger redraw when switching consoles with deferred takeover") Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-07-06Drivers: hv: vmbus: Add utility function for querying ring sizeSaurabh Sengar
[ Upstream commit e8c4bd6c6e6b7e7b416c42806981c2a81370001e ] Add a function to query for the preferred ring buffer size of VMBus device. This will allow the drivers (eg. UIO) to allocate the most optimized ring buffer size for devices. Signed-off-by: Saurabh Sengar <ssengar@linux.microsoft.com> Reviewed-by: Long Li <longli@microsoft.com> Link: https://lore.kernel.org/r/1711788723-8593-2-git-send-email-ssengar@linux.microsoft.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Stable-dep-of: 0315fef2aff9 ("uio_hv_generic: Align ring size to system page") Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-06-27net: make for_each_netdev_dump() a little more bug-proofJakub Kicinski
commit f22b4b55edb507a2b30981e133b66b642be4d13f upstream. I find the behavior of xa_for_each_start() slightly counter-intuitive. It doesn't end the iteration by making the index point after the last element. IOW calling xa_for_each_start() again after it "finished" will run the body of the loop for the last valid element, instead of doing nothing. This works fine for netlink dumps if they terminate correctly (i.e. coalesce or carefully handle NLM_DONE), but as we keep getting reminded legacy dumps are unlikely to go away. Fixing this generically at the xa_for_each_start() level seems hard - there is no index reserved for "end of iteration". ifindexes are 31b wide, tho, and iterator is ulong so for for_each_netdev_dump() it's safe to go to the next element. Signed-off-by: Jakub Kicinski <kuba@kernel.org> Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net> [ The mctp RTM_GETADDR rework backport of acab78ae12c7 ("net: mctp: Don't access ifa_index when missing") pulled 2d45eeb7d5d7 ("mctp: no longer rely on net->dev_index_head[]") as a dependency. However, that change relies on this backport for correct behaviour of for_each_netdev_dump(). Jakub mentions[1] that nothing should be relying on the old behaviour of for_each_netdev_dump(), hence the backport. [1]: https://lore.kernel.org/netdev/20250609083749.741c27f5@kernel.org/ ] Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-06-27erofs: remove unused trace event erofs_destroy_inodeGao Xiang
commit 30b58444807c93bffeaba7d776110f2a909d2f9a upstream. The trace event `erofs_destroy_inode` was added but remains unused. This unused event contributes approximately 5KB to the kernel module size. Reported-by: Steven Rostedt <rostedt@goodmis.org> Closes: https://lore.kernel.org/r/20250612224906.15000244@batman.local.home Fixes: 13f06f48f7bf ("staging: erofs: support tracepoint") Cc: stable@vger.kernel.org Reviewed-by: Hongbo Li <lihongbo22@huawei.com> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20250617054056.3232365-1-hsiangkao@linux.alibaba.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-06-27bpf: Fix L4 csum update on IPv6 in CHECKSUM_COMPLETEPaul Chaignon
commit ead7f9b8de65632ef8060b84b0c55049a33cfea1 upstream. In Cilium, we use bpf_csum_diff + bpf_l4_csum_replace to, among other things, update the L4 checksum after reverse SNATing IPv6 packets. That use case is however not currently supported and leads to invalid skb->csum values in some cases. This patch adds support for IPv6 address changes in bpf_l4_csum_update via a new flag. When calling bpf_l4_csum_replace in Cilium, it ends up calling inet_proto_csum_replace_by_diff: 1: void inet_proto_csum_replace_by_diff(__sum16 *sum, struct sk_buff *skb, 2: __wsum diff, bool pseudohdr) 3: { 4: if (skb->ip_summed != CHECKSUM_PARTIAL) { 5: csum_replace_by_diff(sum, diff); 6: if (skb->ip_summed == CHECKSUM_COMPLETE && pseudohdr) 7: skb->csum = ~csum_sub(diff, skb->csum); 8: } else if (pseudohdr) { 9: *sum = ~csum_fold(csum_add(diff, csum_unfold(*sum))); 10: } 11: } The bug happens when we're in the CHECKSUM_COMPLETE state. We've just updated one of the IPv6 addresses. The helper now updates the L4 header checksum on line 5. Next, it updates skb->csum on line 7. It shouldn't. For an IPv6 packet, the updates of the IPv6 address and of the L4 checksum will cancel each other. The checksums are set such that computing a checksum over the packet including its checksum will result in a sum of 0. So the same is true here when we update the L4 checksum on line 5. We'll update it as to cancel the previous IPv6 address update. Hence skb->csum should remain untouched in this case. The same bug doesn't affect IPv4 packets because, in that case, three fields are updated: the IPv4 address, the IP checksum, and the L4 checksum. The change to the IPv4 address and one of the checksums still cancel each other in skb->csum, but we're left with one checksum update and should therefore update skb->csum accordingly. That's exactly what inet_proto_csum_replace_by_diff does. This special case for IPv6 L4 checksums is also described atop inet_proto_csum_replace16, the function we should be using in this case. This patch introduces a new bpf_l4_csum_replace flag, BPF_F_IPV6, to indicate that we're updating the L4 checksum of an IPv6 packet. When the flag is set, inet_proto_csum_replace_by_diff will skip the skb->csum update. Fixes: 7d672345ed295 ("bpf: add generic bpf_csum_diff helper") Signed-off-by: Paul Chaignon <paul.chaignon@gmail.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://patch.msgid.link/96a6bc3a443e6f0b21ff7b7834000e17fb549e05.1748509484.git.paul.chaignon@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Paul Chaignon <paul.chaignon@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-06-27net: Fix checksum update for ILA adj-transportPaul Chaignon
commit 6043b794c7668c19dabc4a93c75b924a19474d59 upstream. During ILA address translations, the L4 checksums can be handled in different ways. One of them, adj-transport, consist in parsing the transport layer and updating any found checksum. This logic relies on inet_proto_csum_replace_by_diff and produces an incorrect skb->csum when in state CHECKSUM_COMPLETE. This bug can be reproduced with a simple ILA to SIR mapping, assuming packets are received with CHECKSUM_COMPLETE: $ ip a show dev eth0 14: eth0@if15: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000 link/ether 62:ae:35:9e:0f:8d brd ff:ff:ff:ff:ff:ff link-netnsid 0 inet6 3333:0:0:1::c078/64 scope global valid_lft forever preferred_lft forever inet6 fd00:10:244:1::c078/128 scope global nodad valid_lft forever preferred_lft forever inet6 fe80::60ae:35ff:fe9e:f8d/64 scope link proto kernel_ll valid_lft forever preferred_lft forever $ ip ila add loc_match fd00:10:244:1 loc 3333:0:0:1 \ csum-mode adj-transport ident-type luid dev eth0 Then I hit [fd00:10:244:1::c078]:8000 with a server listening only on [3333:0:0:1::c078]:8000. With the bug, the SYN packet is dropped with SKB_DROP_REASON_TCP_CSUM after inet_proto_csum_replace_by_diff changed skb->csum. The translation and drop are visible on pwru [1] traces: IFACE TUPLE FUNC eth0:9 [fd00:10:244:3::3d8]:51420->[fd00:10:244:1::c078]:8000(tcp) ipv6_rcv eth0:9 [fd00:10:244:3::3d8]:51420->[fd00:10:244:1::c078]:8000(tcp) ip6_rcv_core eth0:9 [fd00:10:244:3::3d8]:51420->[fd00:10:244:1::c078]:8000(tcp) nf_hook_slow eth0:9 [fd00:10:244:3::3d8]:51420->[fd00:10:244:1::c078]:8000(tcp) inet_proto_csum_replace_by_diff eth0:9 [fd00:10:244:3::3d8]:51420->[3333:0:0:1::c078]:8000(tcp) tcp_v6_early_demux eth0:9 [fd00:10:244:3::3d8]:51420->[3333:0:0:1::c078]:8000(tcp) ip6_route_input eth0:9 [fd00:10:244:3::3d8]:51420->[3333:0:0:1::c078]:8000(tcp) ip6_input eth0:9 [fd00:10:244:3::3d8]:51420->[3333:0:0:1::c078]:8000(tcp) ip6_input_finish eth0:9 [fd00:10:244:3::3d8]:51420->[3333:0:0:1::c078]:8000(tcp) ip6_protocol_deliver_rcu eth0:9 [fd00:10:244:3::3d8]:51420->[3333:0:0:1::c078]:8000(tcp) raw6_local_deliver eth0:9 [fd00:10:244:3::3d8]:51420->[3333:0:0:1::c078]:8000(tcp) ipv6_raw_deliver eth0:9 [fd00:10:244:3::3d8]:51420->[3333:0:0:1::c078]:8000(tcp) tcp_v6_rcv eth0:9 [fd00:10:244:3::3d8]:51420->[3333:0:0:1::c078]:8000(tcp) __skb_checksum_complete eth0:9 [fd00:10:244:3::3d8]:51420->[3333:0:0:1::c078]:8000(tcp) kfree_skb_reason(SKB_DROP_REASON_TCP_CSUM) eth0:9 [fd00:10:244:3::3d8]:51420->[3333:0:0:1::c078]:8000(tcp) skb_release_head_state eth0:9 [fd00:10:244:3::3d8]:51420->[3333:0:0:1::c078]:8000(tcp) skb_release_data eth0:9 [fd00:10:244:3::3d8]:51420->[3333:0:0:1::c078]:8000(tcp) skb_free_head eth0:9 [fd00:10:244:3::3d8]:51420->[3333:0:0:1::c078]:8000(tcp) kfree_skbmem This is happening because inet_proto_csum_replace_by_diff is updating skb->csum when it shouldn't. The L4 checksum is updated such that it "cancels" the IPv6 address change in terms of checksum computation, so the impact on skb->csum is null. Note this would be different for an IPv4 packet since three fields would be updated: the IPv4 address, the IP checksum, and the L4 checksum. Two would cancel each other and skb->csum would still need to be updated to take the L4 checksum change into account. This patch fixes it by passing an ipv6 flag to inet_proto_csum_replace_by_diff, to skip the skb->csum update if we're in the IPv6 case. Note the behavior of the only other user of inet_proto_csum_replace_by_diff, the BPF subsystem, is left as is in this patch and fixed in the subsequent patch. With the fix, using the reproduction from above, I can confirm skb->csum is not touched by inet_proto_csum_replace_by_diff and the TCP SYN proceeds to the application after the ILA translation. Link: https://github.com/cilium/pwru [1] Fixes: 65d7ab8de582 ("net: Identifier Locator Addressing module") Signed-off-by: Paul Chaignon <paul.chaignon@gmail.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://patch.msgid.link/b5539869e3550d46068504feb02d37653d939c0b.1748509484.git.paul.chaignon@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Paul Chaignon <paul.chaignon@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-06-27mm/hugetlb: unshare page tables during VMA split, not beforeJann Horn
commit 081056dc00a27bccb55ccc3c6f230a3d5fd3f7e0 upstream. Currently, __split_vma() triggers hugetlb page table unsharing through vm_ops->may_split(). This happens before the VMA lock and rmap locks are taken - which is too early, it allows racing VMA-locked page faults in our process and racing rmap walks from other processes to cause page tables to be shared again before we actually perform the split. Fix it by explicitly calling into the hugetlb unshare logic from __split_vma() in the same place where THP splitting also happens. At that point, both the VMA and the rmap(s) are write-locked. An annoying detail is that we can now call into the helper hugetlb_unshare_pmds() from two different locking contexts: 1. from hugetlb_split(), holding: - mmap lock (exclusively) - VMA lock - file rmap lock (exclusively) 2. hugetlb_unshare_all_pmds(), which I think is designed to be able to call us with only the mmap lock held (in shared mode), but currently only runs while holding mmap lock (exclusively) and VMA lock Backporting note: This commit fixes a racy protection that was introduced in commit b30c14cd6102 ("hugetlb: unshare some PMDs when splitting VMAs"); that commit claimed to fix an issue introduced in 5.13, but it should actually also go all the way back. [jannh@google.com: v2] Link: https://lkml.kernel.org/r/20250528-hugetlb-fixes-splitrace-v2-1-1329349bad1a@google.com Link: https://lkml.kernel.org/r/20250528-hugetlb-fixes-splitrace-v2-0-1329349bad1a@google.com Link: https://lkml.kernel.org/r/20250527-hugetlb-fixes-splitrace-v1-1-f4136f5ec58a@google.com Fixes: 39dde65c9940 ("[PATCH] shared page table for hugetlb page") Signed-off-by: Jann Horn <jannh@google.com> Cc: Liam Howlett <liam.howlett@oracle.com> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: <stable@vger.kernel.org> [b30c14cd6102: hugetlb: unshare some PMDs when splitting VMAs] Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> [stable backport: code got moved from mmap.c to vma.c] Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-06-27atm: Revert atm_account_tx() if copy_from_iter_full() fails.Kuniyuki Iwashima
commit 7851263998d4269125fd6cb3fdbfc7c6db853859 upstream. In vcc_sendmsg(), we account skb->truesize to sk->sk_wmem_alloc by atm_account_tx(). It is expected to be reverted by atm_pop_raw() later called by vcc->dev->ops->send(vcc, skb). However, vcc_sendmsg() misses the same revert when copy_from_iter_full() fails, and then we will leak a socket. Let's factorise the revert part as atm_return_tx() and call it in the failure path. Note that the corresponding sk_wmem_alloc operation can be found in alloc_tx() as of the blamed commit. $ git blame -L:alloc_tx net/atm/common.c c55fa3cccbc2c~ Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: Simon Horman <horms@kernel.org> Closes: https://lore.kernel.org/netdev/20250614161959.GR414686@horms.kernel.org/ Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com> Link: https://patch.msgid.link/20250616182147.963333-3-kuni1840@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-06-27ACPI: Add missing prototype for non CONFIG_SUSPEND/CONFIG_X86 caseMario Limonciello
[ Upstream commit e1bdbbc98279164d910d2de82a745f090a8b249f ] acpi_register_lps0_dev() and acpi_unregister_lps0_dev() may be used in drivers that don't require CONFIG_SUSPEND or compile on !X86. Add prototypes for those cases. Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202502191627.fRgoBwcZ-lkp@intel.com/ Signed-off-by: Mario Limonciello <mario.limonciello@amd.com> Link: https://patch.msgid.link/20250407183656.1503446-1-superm1@kernel.org Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-06-27ACPICA: Avoid sequence overread in call to strncmp()Ahmed Salem
[ Upstream commit 64b9dfd0776e9c38d733094859a09f13282ce6f8 ] ACPICA commit 8b83a8d88dfec59ea147fad35fc6deea8859c58c ap_get_table_length() checks if tables are valid by calling ap_is_valid_header(). The latter then calls ACPI_VALIDATE_RSDP_SIG(Table->Signature). ap_is_valid_header() accepts struct acpi_table_header as an argument, so the signature size is always fixed to 4 bytes. The problem is when the string comparison is between ACPI-defined table signature and ACPI_SIG_RSDP. Common ACPI table header specifies the Signature field to be 4 bytes long[1], with the exception of the RSDP structure whose signature is 8 bytes long "RSD PTR " (including the trailing blank character)[2]. Calling strncmp(sig, rsdp_sig, 8) would then result in a sequence overread[3] as sig would be smaller (4 bytes) than the specified bound (8 bytes). As a workaround, pass the bound conditionally based on the size of the signature being passed. Link: https://uefi.org/specs/ACPI/6.5_A/05_ACPI_Software_Programming_Model.html#system-description-table-header [1] Link: https://uefi.org/specs/ACPI/6.5_A/05_ACPI_Software_Programming_Model.html#root-system-description-pointer-rsdp-structure [2] Link: https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html#index-Wstringop-overread [3] Link: https://github.com/acpica/acpica/commit/8b83a8d8 Signed-off-by: Ahmed Salem <x0rw3ll@gmail.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Link: https://patch.msgid.link/2248233.Mh6RI2rZIc@rjwysocki.net Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-06-27mmc: Add quirk to disable DDR50 tuningErick Shepherd
[ Upstream commit 9510b38dc0ba358c93cbf5ee7c28820afb85937b ] Adds the MMC_QUIRK_NO_UHS_DDR50_TUNING quirk and updates mmc_execute_tuning() to return 0 if that quirk is set. This fixes an issue on certain Swissbit SD cards that do not support DDR50 tuning where tuning requests caused I/O errors to be thrown. Signed-off-by: Erick Shepherd <erick.shepherd@ni.com> Acked-by: Adrian Hunter <adrian.hunter@intel.com> Link: https://lore.kernel.org/r/20250331221337.1414534-1-erick.shepherd@ni.com Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-06-19io_uring: add io_file_can_poll() helperJens Axboe
Commit 95041b93e90a06bb613ec4bef9cd4d61570f68e4 upstream. This adds a flag to avoid dipping dereferencing file and then f_op to figure out if the file has a poll handler defined or not. We generally call this at least twice for networked workloads, and if using ring provided buffers, we do it on every buffer selection. Particularly the latter is troublesome, as it's otherwise a very fast operation. Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-06-19HID: usbhid: Eliminate recurrent out-of-bounds bug in usbhid_parse()Terry Junge
commit fe7f7ac8e0c708446ff017453add769ffc15deed upstream. Update struct hid_descriptor to better reflect the mandatory and optional parts of the HID Descriptor as per USB HID 1.11 specification. Note: the kernel currently does not parse any optional HID class descriptors, only the mandatory report descriptor. Update all references to member element desc[0] to rpt_desc. Add test to verify bLength and bNumDescriptors values are valid. Replace the for loop with direct access to the mandatory HID class descriptor member for the report descriptor. This eliminates the possibility of getting an out-of-bounds fault. Add a warning message if the HID descriptor contains any unsupported optional HID class descriptors. Reported-by: syzbot+c52569baf0c843f35495@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=c52569baf0c843f35495 Fixes: f043bfc98c19 ("HID: usbhid: fix out-of-bounds bug") Cc: stable@vger.kernel.org Signed-off-by: Terry Junge <linuxhid@cosmicgizmosystems.com> Reviewed-by: Michael Kelley <mhklinux@outlook.com> Signed-off-by: Jiri Kosina <jkosina@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-06-19block: Fix bvec_set_folio() for very large foliosMatthew Wilcox (Oracle)
[ Upstream commit 5e223e06ee7c6d8f630041a0645ac90e39a42cc6 ] Similarly to 26064d3e2b4d ("block: fix adding folio to bio"), if we attempt to add a folio that is larger than 4GB, we'll silently truncate the offset and len. Widen the parameters to size_t, assert that the length is less than 4GB and set the first page that contains the interesting data rather than the first page of the folio. Fixes: 26db5ee15851 (block: add a bvec_set_folio helper) Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Link: https://lore.kernel.org/r/20250612144255.2850278-1-willy@infradead.org Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-06-19bio: Fix bio_first_folio() for SPARSEMEM without VMEMMAPMatthew Wilcox (Oracle)
[ Upstream commit f826ec7966a63d48e16e0868af4e038bf9a1a3ae ] It is possible for physically contiguous folios to have discontiguous struct pages if SPARSEMEM is enabled and SPARSEMEM_VMEMMAP is not. This is correctly handled by folio_page_idx(), so remove this open-coded implementation. Fixes: 640d1930bef4 (block: Add bio_for_each_folio_all()) Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Link: https://lore.kernel.org/r/20250612144126.2849931-1-willy@infradead.org Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-06-19net: Fix TOCTOU issue in sk_is_readable()Michal Luczaj
[ Upstream commit 2660a544fdc0940bba15f70508a46cf9a6491230 ] sk->sk_prot->sock_is_readable is a valid function pointer when sk resides in a sockmap. After the last sk_psock_put() (which usually happens when socket is removed from sockmap), sk->sk_prot gets restored and sk->sk_prot->sock_is_readable becomes NULL. This makes sk_is_readable() racy, if the value of sk->sk_prot is reloaded after the initial check. Which in turn may lead to a null pointer dereference. Ensure the function pointer does not turn NULL after the check. Fixes: 8934ce2fd081 ("bpf: sockmap redirect ingress support") Suggested-by: Jakub Sitnicki <jakub@cloudflare.com> Signed-off-by: Michal Luczaj <mhal@rbox.co> Reviewed-by: Willem de Bruijn <willemb@google.com> Link: https://patch.msgid.link/20250609-skisreadable-toctou-v1-1-d0dfb2d62c37@rbox.co Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-06-19Bluetooth: MGMT: Protect mgmt_pending list with its own lockLuiz Augusto von Dentz
[ Upstream commit 6fe26f694c824b8a4dbf50c635bee1302e3f099c ] This uses a mutex to protect from concurrent access of mgmt_pending list which can cause crashes like: ================================================================== BUG: KASAN: slab-use-after-free in hci_sock_get_channel+0x60/0x68 net/bluetooth/hci_sock.c:91 Read of size 2 at addr ffff0000c48885b2 by task syz.4.334/7318 CPU: 0 UID: 0 PID: 7318 Comm: syz.4.334 Not tainted 6.15.0-rc7-syzkaller-g187899f4124a #0 PREEMPT Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call trace: show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:466 (C) __dump_stack+0x30/0x40 lib/dump_stack.c:94 dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120 print_address_description+0xa8/0x254 mm/kasan/report.c:408 print_report+0x68/0x84 mm/kasan/report.c:521 kasan_report+0xb0/0x110 mm/kasan/report.c:634 __asan_report_load2_noabort+0x20/0x2c mm/kasan/report_generic.c:379 hci_sock_get_channel+0x60/0x68 net/bluetooth/hci_sock.c:91 mgmt_pending_find+0x7c/0x140 net/bluetooth/mgmt_util.c:223 pending_find net/bluetooth/mgmt.c:947 [inline] remove_adv_monitor+0x44/0x1a4 net/bluetooth/mgmt.c:5445 hci_mgmt_cmd+0x780/0xc00 net/bluetooth/hci_sock.c:1712 hci_sock_sendmsg+0x544/0xbb0 net/bluetooth/hci_sock.c:1832 sock_sendmsg_nosec net/socket.c:712 [inline] __sock_sendmsg net/socket.c:727 [inline] sock_write_iter+0x25c/0x378 net/socket.c:1131 new_sync_write fs/read_write.c:591 [inline] vfs_write+0x62c/0x97c fs/read_write.c:684 ksys_write+0x120/0x210 fs/read_write.c:736 __do_sys_write fs/read_write.c:747 [inline] __se_sys_write fs/read_write.c:744 [inline] __arm64_sys_write+0x7c/0x90 fs/read_write.c:744 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x58/0x17c arch/arm64/kernel/entry-common.c:767 el0t_64_sync_handler+0x78/0x108 arch/arm64/kernel/entry-common.c:786 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600 Allocated by task 7037: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x40/0x78 mm/kasan/common.c:68 kasan_save_alloc_info+0x44/0x54 mm/kasan/generic.c:562 poison_kmalloc_redzone mm/kasan/common.c:377 [inline] __kasan_kmalloc+0x9c/0xb4 mm/kasan/common.c:394 kasan_kmalloc include/linux/kasan.h:260 [inline] __do_kmalloc_node mm/slub.c:4327 [inline] __kmalloc_noprof+0x2fc/0x4c8 mm/slub.c:4339 kmalloc_noprof include/linux/slab.h:909 [inline] sk_prot_alloc+0xc4/0x1f0 net/core/sock.c:2198 sk_alloc+0x44/0x3ac net/core/sock.c:2254 bt_sock_alloc+0x4c/0x300 net/bluetooth/af_bluetooth.c:148 hci_sock_create+0xa8/0x194 net/bluetooth/hci_sock.c:2202 bt_sock_create+0x14c/0x24c net/bluetooth/af_bluetooth.c:132 __sock_create+0x43c/0x91c net/socket.c:1541 sock_create net/socket.c:1599 [inline] __sys_socket_create net/socket.c:1636 [inline] __sys_socket+0xd4/0x1c0 net/socket.c:1683 __do_sys_socket net/socket.c:1697 [inline] __se_sys_socket net/socket.c:1695 [inline] __arm64_sys_socket+0x7c/0x94 net/socket.c:1695 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x58/0x17c arch/arm64/kernel/entry-common.c:767 el0t_64_sync_handler+0x78/0x108 arch/arm64/kernel/entry-common.c:786 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600 Freed by task 6607: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x40/0x78 mm/kasan/common.c:68 kasan_save_free_info+0x58/0x70 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:247 [inline] __kasan_slab_free+0x68/0x88 mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2380 [inline] slab_free mm/slub.c:4642 [inline] kfree+0x17c/0x474 mm/slub.c:4841 sk_prot_free net/core/sock.c:2237 [inline] __sk_destruct+0x4f4/0x760 net/core/sock.c:2332 sk_destruct net/core/sock.c:2360 [inline] __sk_free+0x320/0x430 net/core/sock.c:2371 sk_free+0x60/0xc8 net/core/sock.c:2382 sock_put include/net/sock.h:1944 [inline] mgmt_pending_free+0x88/0x118 net/bluetooth/mgmt_util.c:290 mgmt_pending_remove+0xec/0x104 net/bluetooth/mgmt_util.c:298 mgmt_set_powered_complete+0x418/0x5cc net/bluetooth/mgmt.c:1355 hci_cmd_sync_work+0x204/0x33c net/bluetooth/hci_sync.c:334 process_one_work+0x7e8/0x156c kernel/workqueue.c:3238 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x958/0xed8 kernel/workqueue.c:3400 kthread+0x5fc/0x75c kernel/kthread.c:464 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:847 Fixes: a380b6cff1a2 ("Bluetooth: Add generic mgmt helper API") Closes: https://syzkaller.appspot.com/bug?extid=0a7039d5d9986ff4ecec Closes: https://syzkaller.appspot.com/bug?extid=cc0cc52e7f43dc9e6df1 Reported-by: syzbot+0a7039d5d9986ff4ecec@syzkaller.appspotmail.com Tested-by: syzbot+0a7039d5d9986ff4ecec@syzkaller.appspotmail.com Tested-by: syzbot+cc0cc52e7f43dc9e6df1@syzkaller.appspotmail.com Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru> Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-06-19Bluetooth: MGMT: Fix UAF on mgmt_remove_adv_monitor_completeLuiz Augusto von Dentz
[ Upstream commit e6ed54e86aae9e4f7286ce8d5c73780f91b48d1c ] This reworks MGMT_OP_REMOVE_ADV_MONITOR to not use mgmt_pending_add to avoid crashes like bellow: ================================================================== BUG: KASAN: slab-use-after-free in mgmt_remove_adv_monitor_complete+0xe5/0x540 net/bluetooth/mgmt.c:5406 Read of size 8 at addr ffff88801c53f318 by task kworker/u5:5/5341 CPU: 0 UID: 0 PID: 5341 Comm: kworker/u5:5 Not tainted 6.15.0-syzkaller-10402-g4cb6c8af8591 #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Workqueue: hci0 hci_cmd_sync_work Call Trace: <TASK> dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:408 [inline] print_report+0xd2/0x2b0 mm/kasan/report.c:521 kasan_report+0x118/0x150 mm/kasan/report.c:634 mgmt_remove_adv_monitor_complete+0xe5/0x540 net/bluetooth/mgmt.c:5406 hci_cmd_sync_work+0x261/0x3a0 net/bluetooth/hci_sync.c:334 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3321 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402 kthread+0x711/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 </TASK> Allocated by task 5987: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:377 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:394 kasan_kmalloc include/linux/kasan.h:260 [inline] __kmalloc_cache_noprof+0x230/0x3d0 mm/slub.c:4358 kmalloc_noprof include/linux/slab.h:905 [inline] kzalloc_noprof include/linux/slab.h:1039 [inline] mgmt_pending_new+0x65/0x240 net/bluetooth/mgmt_util.c:252 mgmt_pending_add+0x34/0x120 net/bluetooth/mgmt_util.c:279 remove_adv_monitor+0x103/0x1b0 net/bluetooth/mgmt.c:5454 hci_mgmt_cmd+0x9c9/0xef0 net/bluetooth/hci_sock.c:1719 hci_sock_sendmsg+0x6ca/0xef0 net/bluetooth/hci_sock.c:1839 sock_sendmsg_nosec net/socket.c:712 [inline] __sock_sendmsg+0x219/0x270 net/socket.c:727 sock_write_iter+0x258/0x330 net/socket.c:1131 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x548/0xa90 fs/read_write.c:686 ksys_write+0x145/0x250 fs/read_write.c:738 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 5989: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:247 [inline] __kasan_slab_free+0x62/0x70 mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2380 [inline] slab_free mm/slub.c:4642 [inline] kfree+0x18e/0x440 mm/slub.c:4841 mgmt_pending_foreach+0xc9/0x120 net/bluetooth/mgmt_util.c:242 mgmt_index_removed+0x10d/0x2f0 net/bluetooth/mgmt.c:9366 hci_sock_bind+0xbe9/0x1000 net/bluetooth/hci_sock.c:1314 __sys_bind_socket net/socket.c:1810 [inline] __sys_bind+0x2c3/0x3e0 net/socket.c:1841 __do_sys_bind net/socket.c:1846 [inline] __se_sys_bind net/socket.c:1844 [inline] __x64_sys_bind+0x7a/0x90 net/socket.c:1844 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Fixes: 66bd095ab5d4 ("Bluetooth: advmon offload MSFT remove monitor") Closes: https://syzkaller.appspot.com/bug?extid=feb0dc579bbe30a13190 Reported-by: syzbot+feb0dc579bbe30a13190@syzkaller.appspotmail.com Tested-by: syzbot+feb0dc579bbe30a13190@syzkaller.appspotmail.com Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-06-19net: phy: fix up const issues in to_mdio_device() and to_phy_device()Greg Kroah-Hartman
[ Upstream commit e9cb929670a1e98b592b30f03f06e9e20110f318 ] Both to_mdio_device() and to_phy_device() "throw away" the const pointer attribute passed to them and return a non-const pointer, which generally is not a good thing overall. Fix this up by using container_of_const() which was designed for this very problem. Cc: Alexander Lobakin <alobakin@pm.me> Cc: Andrew Lunn <andrew@lunn.ch> Cc: Heiner Kallweit <hkallweit1@gmail.com> Cc: Russell King <linux@armlinux.org.uk> Fixes: 7eab14de73a8 ("mdio, phy: fix -Wshadow warnings triggered by nested container_of()") Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Link: https://patch.msgid.link/2025052246-conduit-glory-8fc9@gregkh Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-06-19RDMA/mlx5: Fix error flow upon firmware failure for RQ destructionPatrisious Haddad
[ Upstream commit 5d2ea5aebbb2f3ebde4403f9c55b2b057e5dd2d6 ] Upon RQ destruction if the firmware command fails which is the last resource to be destroyed some SW resources were already cleaned regardless of the failure. Now properly rollback the object to its original state upon such failure. In order to avoid a use-after free in case someone tries to destroy the object again, which results in the following kernel trace: refcount_t: underflow; use-after-free. WARNING: CPU: 0 PID: 37589 at lib/refcount.c:28 refcount_warn_saturate+0xf4/0x148 Modules linked in: rdma_ucm(OE) rdma_cm(OE) iw_cm(OE) ib_ipoib(OE) ib_cm(OE) ib_umad(OE) mlx5_ib(OE) rfkill mlx5_core(OE) mlxdevm(OE) ib_uverbs(OE) ib_core(OE) psample mlxfw(OE) mlx_compat(OE) macsec tls pci_hyperv_intf sunrpc vfat fat virtio_net net_failover failover fuse loop nfnetlink vsock_loopback vmw_vsock_virtio_transport_common vmw_vsock_vmci_transport vmw_vmci vsock xfs crct10dif_ce ghash_ce sha2_ce sha256_arm64 sha1_ce virtio_console virtio_gpu virtio_blk virtio_dma_buf virtio_mmio dm_mirror dm_region_hash dm_log dm_mod xpmem(OE) CPU: 0 UID: 0 PID: 37589 Comm: python3 Kdump: loaded Tainted: G OE ------- --- 6.12.0-54.el10.aarch64 #1 Tainted: [O]=OOT_MODULE, [E]=UNSIGNED_MODULE Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015 pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : refcount_warn_saturate+0xf4/0x148 lr : refcount_warn_saturate+0xf4/0x148 sp : ffff80008b81b7e0 x29: ffff80008b81b7e0 x28: ffff000133d51600 x27: 0000000000000001 x26: 0000000000000000 x25: 00000000ffffffea x24: ffff00010ae80f00 x23: ffff00010ae80f80 x22: ffff0000c66e5d08 x21: 0000000000000000 x20: ffff0000c66e0000 x19: ffff00010ae80340 x18: 0000000000000006 x17: 0000000000000000 x16: 0000000000000020 x15: ffff80008b81b37f x14: 0000000000000000 x13: 2e656572662d7265 x12: ffff80008283ef78 x11: ffff80008257efd0 x10: ffff80008283efd0 x9 : ffff80008021ed90 x8 : 0000000000000001 x7 : 00000000000bffe8 x6 : c0000000ffff7fff x5 : ffff0001fb8e3408 x4 : 0000000000000000 x3 : ffff800179993000 x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff000133d51600 Call trace: refcount_warn_saturate+0xf4/0x148 mlx5_core_put_rsc+0x88/0xa0 [mlx5_ib] mlx5_core_destroy_rq_tracked+0x64/0x98 [mlx5_ib] mlx5_ib_destroy_wq+0x34/0x80 [mlx5_ib] ib_destroy_wq_user+0x30/0xc0 [ib_core] uverbs_free_wq+0x28/0x58 [ib_uverbs] destroy_hw_idr_uobject+0x34/0x78 [ib_uverbs] uverbs_destroy_uobject+0x48/0x240 [ib_uverbs] __uverbs_cleanup_ufile+0xd4/0x1a8 [ib_uverbs] uverbs_destroy_ufile_hw+0x48/0x120 [ib_uverbs] ib_uverbs_close+0x2c/0x100 [ib_uverbs] __fput+0xd8/0x2f0 __fput_sync+0x50/0x70 __arm64_sys_close+0x40/0x90 invoke_syscall.constprop.0+0x74/0xd0 do_el0_svc+0x48/0xe8 el0_svc+0x44/0x1d0 el0t_64_sync_handler+0x120/0x130 el0t_64_sync+0x1a4/0x1a8 Fixes: e2013b212f9f ("net/mlx5_core: Add RQ and SQ event handling") Signed-off-by: Patrisious Haddad <phaddad@nvidia.com> Link: https://patch.msgid.link/3181433ccdd695c63560eeeb3f0c990961732101.1745839855.git.leon@kernel.org Signed-off-by: Leon Romanovsky <leon@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-06-19firmware: SDEI: Allow sdei initialization without ACPI_APEI_GHESHuang Yiwei
[ Upstream commit 59529bbe642de4eb2191a541d9b4bae7eb73862e ] SDEI usually initialize with the ACPI table, but on platforms where ACPI is not used, the SDEI feature can still be used to handle specific firmware calls or other customized purposes. Therefore, it is not necessary for ARM_SDE_INTERFACE to depend on ACPI_APEI_GHES. In commit dc4e8c07e9e2 ("ACPI: APEI: explicit init of HEST and GHES in acpi_init()"), to make APEI ready earlier, sdei_init was moved into acpi_ghes_init instead of being a standalone initcall, adding ACPI_APEI_GHES dependency to ARM_SDE_INTERFACE. This restricts the flexibility and usability of SDEI. This patch corrects the dependency in Kconfig and splits sdei_init() into two separate functions: sdei_init() and acpi_sdei_init(). sdei_init() will be called by arch_initcall and will only initialize the platform driver, while acpi_sdei_init() will initialize the device from acpi_ghes_init() when ACPI is ready. This allows the initialization of SDEI without ACPI_APEI_GHES enabled. Fixes: dc4e8c07e9e2 ("ACPI: APEI: explicit init of HEST and GHES in apci_init()") Cc: Shuai Xue <xueshuai@linux.alibaba.com> Signed-off-by: Huang Yiwei <quic_hyiwei@quicinc.com> Reviewed-by: Shuai Xue <xueshuai@linux.alibaba.com> Reviewed-by: Gavin Shan <gshan@redhat.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Link: https://lore.kernel.org/r/20250507045757.2658795-1-quic_hyiwei@quicinc.com Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-06-04NFS: Avoid flushing data while holding directory locks in nfs_rename()Trond Myklebust
[ Upstream commit dcd21b609d4abc7303f8683bce4f35d78d7d6830 ] The Linux client assumes that all filehandles are non-volatile for renames within the same directory (otherwise sillyrename cannot work). However, the existence of the Linux 'subtree_check' export option has meant that nfs_rename() has always assumed it needs to flush writes before attempting to rename. Since NFSv4 does allow the client to query whether or not the server exhibits this behaviour, and since knfsd does actually set the appropriate flag when 'subtree_check' is enabled on an export, it should be OK to optimise away the write flushing behaviour in the cases where it is clearly not needed. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-06-04coredump: hand a pidfd to the usermode coredump helperChristian Brauner
commit b5325b2a270fcaf7b2a9a0f23d422ca8a5a8bdea upstream. Give userspace a way to instruct the kernel to install a pidfd into the usermode helper process. This makes coredump handling a lot more reliable for userspace. In parallel with this commit we already have systemd adding support for this in [1]. We create a pidfs file for the coredumping process when we process the corename pattern. When the usermode helper process is forked we then install the pidfs file as file descriptor three into the usermode helpers file descriptor table so it's available to the exec'd program. Since usermode helpers are either children of the system_unbound_wq workqueue or kthreadd we know that the file descriptor table is empty and can thus always use three as the file descriptor number. Note, that we'll install a pidfd for the thread-group leader even if a subthread is calling do_coredump(). We know that task linkage hasn't been removed due to delay_group_leader() and even if this @current isn't the actual thread-group leader we know that the thread-group leader cannot be reaped until @current has exited. [brauner: This is a backport for the v6.6 series. Upsteam has significantly changed and backporting all that infra is a non-starter. So simply use the pidfd_prepare() helper and waste the file descriptor we allocated. Then we minimally massage the umh coredump setup code.] Link: https://github.com/systemd/systemd/pull/37125 [1] Link: https://lore.kernel.org/20250414-work-coredump-v2-3-685bf231f828@kernel.org Tested-by: Luca Boccassi <luca.boccassi@gmail.com> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-06-04af_unix: Add dead flag to struct scm_fp_list.Kuniyuki Iwashima
commit 7172dc93d621d5dc302d007e95ddd1311ec64283 upstream. Commit 1af2dface5d2 ("af_unix: Don't access successor in unix_del_edges() during GC.") fixed use-after-free by avoid accessing edge->successor while GC is in progress. However, there could be a small race window where another process could call unix_del_edges() while gc_in_progress is true and __skb_queue_purge() is on the way. So, we need another marker for struct scm_fp_list which indicates if the skb is garbage-collected. This patch adds dead flag in struct scm_fp_list and set it true before calling __skb_queue_purge(). Fixes: 1af2dface5d2 ("af_unix: Don't access successor in unix_del_edges() during GC.") Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Acked-by: Paolo Abeni <pabeni@redhat.com> Link: https://lore.kernel.org/r/20240508171150.50601-1-kuniyu@amazon.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Lee Jones <lee@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-06-04af_unix: Try not to hold unix_gc_lock during accept().Kuniyuki Iwashima
commit fd86344823b521149bb31d91eba900ba3525efa6 upstream. Commit dcf70df2048d ("af_unix: Fix up unix_edge.successor for embryo socket.") added spin_lock(&unix_gc_lock) in accept() path, and it caused regression in a stress test as reported by kernel test robot. If the embryo socket is not part of the inflight graph, we need not hold the lock. To decide that in O(1) time and avoid the regression in the normal use case, 1. add a new stat unix_sk(sk)->scm_stat.nr_unix_fds 2. count the number of inflight AF_UNIX sockets in the receive queue under unix_state_lock() 3. move unix_update_edges() call under unix_state_lock() 4. avoid locking if nr_unix_fds is 0 in unix_update_edges() Reported-by: kernel test robot <oliver.sang@intel.com> Closes: https://lore.kernel.org/oe-lkp/202404101427.92a08551-oliver.sang@intel.com Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Link: https://lore.kernel.org/r/20240413021928.20946-1-kuniyu@amazon.com Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Lee Jones <lee@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-06-04af_unix: Remove lock dance in unix_peek_fds().Kuniyuki Iwashima
commit 118f457da9ed58a79e24b73c2ef0aa1987241f0e upstream. In the previous GC implementation, the shape of the inflight socket graph was not expected to change while GC was in progress. MSG_PEEK was tricky because it could install inflight fd silently and transform the graph. Let's say we peeked a fd, which was a listening socket, and accept()ed some embryo sockets from it. The garbage collection algorithm would have been confused because the set of sockets visited in scan_inflight() would change within the same GC invocation. That's why we placed spin_lock(&unix_gc_lock) and spin_unlock() in unix_peek_fds() with a fat comment. In the new GC implementation, we no longer garbage-collect the socket if it exists in another queue, that is, if it has a bridge to another SCC. Also, accept() will require the lock if it has edges. Thus, we need not do the complicated lock dance. Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Link: https://lore.kernel.org/r/20240401173125.92184-3-kuniyu@amazon.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Lee Jones <lee@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-06-04af_unix: Replace garbage collection algorithm.Kuniyuki Iwashima
commit 4090fa373f0e763c43610853d2774b5979915959 upstream. If we find a dead SCC during iteration, we call unix_collect_skb() to splice all skb in the SCC to the global sk_buff_head, hitlist. After iterating all SCC, we unlock unix_gc_lock and purge the queue. Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Acked-by: Paolo Abeni <pabeni@redhat.com> Link: https://lore.kernel.org/r/20240325202425.60930-15-kuniyu@amazon.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Lee Jones <lee@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-06-04af_unix: Assign a unique index to SCC.Kuniyuki Iwashima
commit bfdb01283ee8f2f3089656c3ff8f62bb072dabb2 upstream. The definition of the lowlink in Tarjan's algorithm is the smallest index of a vertex that is reachable with at most one back-edge in SCC. This is not useful for a cross-edge. If we start traversing from A in the following graph, the final lowlink of D is 3. The cross-edge here is one between D and C. A -> B -> D D = (4, 3) (index, lowlink) ^ | | C = (3, 1) | V | B = (2, 1) `--- C <--' A = (1, 1) This is because the lowlink of D is updated with the index of C. In the following patch, we detect a dead SCC by checking two conditions for each vertex. 1) vertex has no edge directed to another SCC (no bridge) 2) vertex's out_degree is the same as the refcount of its file If 1) is false, there is a receiver of all fds of the SCC and its ancestor SCC. To evaluate 1), we need to assign a unique index to each SCC and assign it to all vertices in the SCC. This patch changes the lowlink update logic for cross-edge so that in the example above, the lowlink of D is updated with the lowlink of C. A -> B -> D D = (4, 1) (index, lowlink) ^ | | C = (3, 1) | V | B = (2, 1) `--- C <--' A = (1, 1) Then, all vertices in the same SCC have the same lowlink, and we can quickly find the bridge connecting to different SCC if exists. However, it is no longer called lowlink, so we rename it to scc_index. (It's sometimes called lowpoint.) Also, we add a global variable to hold the last index used in DFS so that we do not reset the initial index in each DFS. This patch can be squashed to the SCC detection patch but is split deliberately for anyone wondering why lowlink is not used as used in the original Tarjan's algorithm and many reference implementations. Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Acked-by: Paolo Abeni <pabeni@redhat.com> Link: https://lore.kernel.org/r/20240325202425.60930-13-kuniyu@amazon.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Lee Jones <lee@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>