user/sven/linux.git/include, branch v4.9.188

include/linux/module.h: copy init/exit attrs to init/cleanup_module

2019-08-06T16:29:42Z

commit a6e60d84989fa0e91db7f236eda40453b0e44afa upstream. The upcoming GCC 9 release extends the -Wmissing-attributes warnings (enabled by -Wall) to C and aliases: it warns when particular function attributes are missing in the aliases but not in their target. In particular, it triggers for all the init/cleanup_module aliases in the kernel (defined by the module_init/exit macros), ending up being very noisy. These aliases point to the __init/__exit functions of a module, which are defined as __cold (among other attributes). However, the aliases themselves do not have the __cold attribute. Since the compiler behaves differently when compiling a __cold function as well as when compiling paths leading to calls to __cold functions, the warning is trying to point out the possibly-forgotten attribute in the alias. In order to keep the warning enabled, we decided to silence this case. Ideally, we would mark the aliases directly as __init/__exit. However, there are currently around 132 modules in the kernel which are missing __init/__exit in their init/cleanup functions (either because they are missing, or for other reasons, e.g. the functions being called from somewhere else); and a section mismatch is a hard error. A conservative alternative was to mark the aliases as __cold only. However, since we would like to eventually enforce __init/__exit to be always marked, we chose to use the new __copy function attribute (introduced by GCC 9 as well to deal with this). With it, we copy the attributes used by the target functions into the aliases. This way, functions that were not marked as __init/__exit won't have their aliases marked either, and therefore there won't be a section mismatch. Note that the warning would go away marking either the extern declaration, the definition, or both. However, we only mark the definition of the alias, since we do not want callers (which only see the declaration) to be compiled as if the function was __cold (and therefore the paths leading to those calls would be assumed to be unlikely). Link: https://lore.kernel.org/lkml/259986242.BvXPX32bHu@devpool35/ Cc: Link: https://lore.kernel.org/lkml/20190123173707.GA16603@gmail.com/ Link: https://lore.kernel.org/lkml/20190206175627.GA20399@gmail.com/ Suggested-by: Martin Sebor Acked-by: Jessica Yu Signed-off-by: Miguel Ojeda Signed-off-by: Greg Kroah-Hartman

Backport minimal compiler_attributes.h to support GCC 9

2019-08-06T16:29:42Z

This adds support for __copy to v4.9.y so that we can use it in init/exit_module to avoid -Werror=missing-attributes errors on GCC 9. Link: https://lore.kernel.org/lkml/259986242.BvXPX32bHu@devpool35/ Cc: Suggested-by: Rolf Eike Beer Signed-off-by: Miguel Ojeda Signed-off-by: Greg Kroah-Hartman

coredump: fix race condition between collapse_huge_page() and core dumping

2019-08-06T16:29:41Z

commit 59ea6d06cfa9247b586a695c21f94afa7183af74 upstream. When fixing the race conditions between the coredump and the mmap_sem holders outside the context of the process, we focused on mmget_not_zero()/get_task_mm() callers in 04f5866e41fb70 ("coredump: fix race condition between mmget_not_zero()/get_task_mm() and core dumping"), but those aren't the only cases where the mmap_sem can be taken outside of the context of the process as Michal Hocko noticed while backporting that commit to older -stable kernels. If mmgrab() is called in the context of the process, but then the mm_count reference is transferred outside the context of the process, that can also be a problem if the mmap_sem has to be taken for writing through that mm_count reference. khugepaged registration calls mmgrab() in the context of the process, but the mmap_sem for writing is taken later in the context of the khugepaged kernel thread. collapse_huge_page() after taking the mmap_sem for writing doesn't modify any vma, so it's not obvious that it could cause a problem to the coredump, but it happens to modify the pmd in a way that breaks an invariant that pmd_trans_huge_lock() relies upon. collapse_huge_page() needs the mmap_sem for writing just to block concurrent page faults that call pmd_trans_huge_lock(). Specifically the invariant that "!pmd_trans_huge()" cannot become a "pmd_trans_huge()" doesn't hold while collapse_huge_page() runs. The coredump will call __get_user_pages() without mmap_sem for reading, which eventually can invoke a lockless page fault which will need a functional pmd_trans_huge_lock(). So collapse_huge_page() needs to use mmget_still_valid() to check it's not running concurrently with the coredump... as long as the coredump can invoke page faults without holding the mmap_sem for reading. This has "Fixes: khugepaged" to facilitate backporting, but in my view it's more a bug in the coredump code that will eventually have to be rewritten to stop invoking page faults without the mmap_sem for reading. So the long term plan is still to drop all mmget_still_valid(). Link: http://lkml.kernel.org/r/20190607161558.32104-1-aarcange@redhat.com Fixes: ba76149f47d8 ("thp: khugepaged") Signed-off-by: Andrea Arcangeli Reported-by: Michal Hocko Acked-by: Michal Hocko Acked-by: Kirill A. Shutemov Cc: Oleg Nesterov Cc: Jann Horn Cc: Hugh Dickins Cc: Mike Rapoport Cc: Mike Kravetz Cc: Peter Xu Cc: Jason Gunthorpe Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds [Ajay: Just adjusted to apply on v4.9] Signed-off-by: Ajay Kaher Signed-off-by: Greg Kroah-Hartman

coredump: fix race condition between mmget_not_zero()/get_task_mm() and core dumping

2019-08-06T16:29:41Z

commit 04f5866e41fb70690e28397487d8bd8eea7d712a upstream. The core dumping code has always run without holding the mmap_sem for writing, despite that is the only way to ensure that the entire vma layout will not change from under it. Only using some signal serialization on the processes belonging to the mm is not nearly enough. This was pointed out earlier. For example in Hugh's post from Jul 2017: https://lkml.kernel.org/r/alpine.LSU.2.11.1707191716030.2055@eggly.anvils "Not strictly relevant here, but a related note: I was very surprised to discover, only quite recently, how handle_mm_fault() may be called without down_read(mmap_sem) - when core dumping. That seems a misguided optimization to me, which would also be nice to correct" In particular because the growsdown and growsup can move the vm_start/vm_end the various loops the core dump does around the vma will not be consistent if page faults can happen concurrently. Pretty much all users calling mmget_not_zero()/get_task_mm() and then taking the mmap_sem had the potential to introduce unexpected side effects in the core dumping code. Adding mmap_sem for writing around the ->core_dump invocation is a viable long term fix, but it requires removing all copy user and page faults and to replace them with get_dump_page() for all binary formats which is not suitable as a short term fix. For the time being this solution manually covers the places that can confuse the core dump either by altering the vma layout or the vma flags while it runs. Once ->core_dump runs under mmap_sem for writing the function mmget_still_valid() can be dropped. Allowing mmap_sem protected sections to run in parallel with the coredump provides some minor parallelism advantage to the swapoff code (which seems to be safe enough by never mangling any vma field and can keep doing swapins in parallel to the core dumping) and to some other corner case. In order to facilitate the backporting I added "Fixes: 86039bd3b4e6" however the side effect of this same race condition in /proc/pid/mem should be reproducible since before 2.6.12-rc2 so I couldn't add any other "Fixes:" because there's no hash beyond the git genesis commit. Because find_extend_vma() is the only location outside of the process context that could modify the "mm" structures under mmap_sem for reading, by adding the mmget_still_valid() check to it, all other cases that take the mmap_sem for reading don't need the new check after mmget_not_zero()/get_task_mm(). The expand_stack() in page fault context also doesn't need the new check, because all tasks under core dumping are frozen. Link: http://lkml.kernel.org/r/20190325224949.11068-1-aarcange@redhat.com Fixes: 86039bd3b4e6 ("userfaultfd: add new syscall to provide memory externalization") Signed-off-by: Andrea Arcangeli Reported-by: Jann Horn Suggested-by: Oleg Nesterov Acked-by: Peter Xu Reviewed-by: Mike Rapoport Reviewed-by: Oleg Nesterov Reviewed-by: Jann Horn Acked-by: Jason Gunthorpe Acked-by: Michal Hocko Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds [akaher@vmware.com: stable 4.9 backport - handle binder_update_page_range - mhocko@suse.com] Signed-off-by: Ajay Kaher Signed-off-by: Greg Kroah-Hartman

uapi linux/coda_psdev.h: move upc_req definition from uapi to kernel side headers

2019-08-06T16:29:38Z

[ Upstream commit f90fb3c7e2c13ae829db2274b88b845a75038b8a ] Only users of upc_req in kernel side fs/coda/psdev.c and fs/coda/upcall.c already include linux/coda_psdev.h. Suggested by Jan Harkes in https://lore.kernel.org/lkml/20150531111913.GA23377@cs.cmu.edu/ Fixes these include/uapi/linux/coda_psdev.h compilation errors in userspace: linux/coda_psdev.h:12:19: error: field `uc_chain' has incomplete type struct list_head uc_chain; ^ linux/coda_psdev.h:13:2: error: unknown type name `caddr_t' caddr_t uc_data; ^ linux/coda_psdev.h:14:2: error: unknown type name `u_short' u_short uc_flags; ^ linux/coda_psdev.h:15:2: error: unknown type name `u_short' u_short uc_inSize; /* Size is at most 5000 bytes */ ^ linux/coda_psdev.h:16:2: error: unknown type name `u_short' u_short uc_outSize; ^ linux/coda_psdev.h:17:2: error: unknown type name `u_short' u_short uc_opcode; /* copied from data to save lookup */ ^ linux/coda_psdev.h:19:2: error: unknown type name `wait_queue_head_t' wait_queue_head_t uc_sleep; /* process' wait queue */ ^ Link: http://lkml.kernel.org/r/9f99f5ce6a0563d5266e6cf7aa9585aac2cae971.1558117389.git.jaharkes@cs.cmu.edu Signed-off-by: Mikko Rapeli Signed-off-by: Jan Harkes Cc: Arnd Bergmann Cc: Colin Ian King Cc: Dan Carpenter Cc: David Howells Cc: Fabian Frederick Cc: Sam Protsenko Cc: Yann Droneaud Cc: Zhouyang Jia Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin

coda: fix build using bare-metal toolchain

2019-08-06T16:29:38Z

[ Upstream commit b2a57e334086602be56b74958d9f29b955cd157f ] The kernel is self-contained project and can be built with bare-metal toolchain. But bare-metal toolchain doesn't define __linux__. Because of this u_quad_t type is not defined when using bare-metal toolchain and codafs build fails. This patch fixes it by defining u_quad_t type unconditionally. Link: http://lkml.kernel.org/r/3cbb40b0a57b6f9923a9d67b53473c0b691a3eaa.1558117389.git.jaharkes@cs.cmu.edu Signed-off-by: Sam Protsenko Signed-off-by: Jan Harkes Cc: Arnd Bergmann Cc: Colin Ian King Cc: Dan Carpenter Cc: David Howells Cc: Fabian Frederick Cc: Mikko Rapeli Cc: Yann Droneaud Cc: Zhouyang Jia Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin

ACPI: fix false-positive -Wuninitialized warning

2019-08-06T16:29:36Z

[ Upstream commit dfd6f9ad36368b8dbd5f5a2b2f0a4705ae69a323 ] clang gets confused by an uninitialized variable in what looks to it like a never executed code path: arch/x86/kernel/acpi/boot.c:618:13: error: variable 'polarity' is uninitialized when used here [-Werror,-Wuninitialized] polarity = polarity ? ACPI_ACTIVE_LOW : ACPI_ACTIVE_HIGH; ^~~~~~~~ arch/x86/kernel/acpi/boot.c:606:32: note: initialize the variable 'polarity' to silence this warning int rc, irq, trigger, polarity; ^ = 0 arch/x86/kernel/acpi/boot.c:617:12: error: variable 'trigger' is uninitialized when used here [-Werror,-Wuninitialized] trigger = trigger ? ACPI_LEVEL_SENSITIVE : ACPI_EDGE_SENSITIVE; ^~~~~~~ arch/x86/kernel/acpi/boot.c:606:22: note: initialize the variable 'trigger' to silence this warning int rc, irq, trigger, polarity; ^ = 0 This is unfortunately a design decision in clang and won't be fixed. Changing the acpi_get_override_irq() macro to an inline function reliably avoids the issue. Signed-off-by: Arnd Bergmann Reviewed-by: Andy Shevchenko Reviewed-by: Nathan Chancellor Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin

sched/fair: Don't free p->numa_faults with concurrent readers

2019-08-04T07:33:45Z

commit 16d51a590a8ce3befb1308e0e7ab77f3b661af33 upstream. When going through execve(), zero out the NUMA fault statistics instead of freeing them. During execve, the task is reachable through procfs and the scheduler. A concurrent /proc/*/sched reader can read data from a freed ->numa_faults allocation (confirmed by KASAN) and write it back to userspace. I believe that it would also be possible for a use-after-free read to occur through a race between a NUMA fault and execve(): task_numa_fault() can lead to task_numa_compare(), which invokes task_weight() on the currently running task of a different CPU. Another way to fix this would be to make ->numa_faults RCU-managed or add extra locking, but it seems easier to wipe the NUMA fault statistics on execve. Signed-off-by: Jann Horn Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Petr Mladek Cc: Sergey Senozhatsky Cc: Thomas Gleixner Cc: Will Deacon Fixes: 82727018b0d3 ("sched/numa: Call task_numa_free() from do_execve()") Link: https://lkml.kernel.org/r/20190716152047.14424-1-jannh@google.com Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman

tcp: reset sk_send_head in tcp_write_queue_purge

2019-08-04T07:33:43Z

[ Upstream commit dbbf2d1e4077bab0c65ece2765d3fc69cf7d610f ] tcp_write_queue_purge clears all the SKBs in the write queue but does not reset the sk_send_head. As a result, we can have a NULL pointer dereference anywhere that we use tcp_send_head instead of the tcp_write_queue_tail. For example, after a27fd7a8ed38 (tcp: purge write queue upon RST), we can purge the write queue on RST. Prior to 75c119afe14f (tcp: implement rb-tree based retransmit queue), tcp_push will only check tcp_send_head and then accesses tcp_write_queue_tail to send the actual SKB. As a result, it will dereference a NULL pointer. This has been reported twice for 4.14 where we don't have 75c119afe14f: By Timofey Titovets: [ 422.081094] BUG: unable to handle kernel NULL pointer dereference at 0000000000000038 [ 422.081254] IP: tcp_push+0x42/0x110 [ 422.081314] PGD 0 P4D 0 [ 422.081364] Oops: 0002 [#1] SMP PTI By Yongjian Xu: BUG: unable to handle kernel NULL pointer dereference at 0000000000000038 IP: tcp_push+0x48/0x120 PGD 80000007ff77b067 P4D 80000007ff77b067 PUD 7fd989067 PMD 0 Oops: 0002 [#18] SMP PTI Modules linked in: tcp_diag inet_diag tcp_bbr sch_fq iTCO_wdt iTCO_vendor_support pcspkr ixgbe mdio i2c_i801 lpc_ich joydev input_leds shpchp e1000e igb dca ptp pps_core hwmon mei_me mei ipmi_si ipmi_msghandler sg ses scsi_transport_sas enclosure ext4 jbd2 mbcache sd_mod ahci libahci megaraid_sas wmi ast ttm dm_mirror dm_region_hash dm_log dm_mod dax CPU: 6 PID: 14156 Comm: [ET_NET 6] Tainted: G D 4.14.26-1.el6.x86_64 #1 Hardware name: LENOVO ThinkServer RD440 /ThinkServer RD440, BIOS A0TS80A 09/22/2014 task: ffff8807d78d8140 task.stack: ffffc9000e944000 RIP: 0010:tcp_push+0x48/0x120 RSP: 0018:ffffc9000e947a88 EFLAGS: 00010246 RAX: 00000000000005b4 RBX: ffff880f7cce9c00 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000040 RDI: ffff8807d00f5000 RBP: ffffc9000e947aa8 R08: 0000000000001c84 R09: 0000000000000000 R10: ffff8807d00f5158 R11: 0000000000000000 R12: ffff8807d00f5000 R13: 0000000000000020 R14: 00000000000256d4 R15: 0000000000000000 FS: 00007f5916de9700(0000) GS:ffff88107fd00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000038 CR3: 00000007f8226004 CR4: 00000000001606e0 Call Trace: tcp_sendmsg_locked+0x33d/0xe50 tcp_sendmsg+0x37/0x60 inet_sendmsg+0x39/0xc0 sock_sendmsg+0x49/0x60 sock_write_iter+0xb6/0x100 do_iter_readv_writev+0xec/0x130 ? rw_verify_area+0x49/0xb0 do_iter_write+0x97/0xd0 vfs_writev+0x7e/0xe0 ? __wake_up_common_lock+0x80/0xa0 ? __fget_light+0x2c/0x70 ? __do_page_fault+0x1e7/0x530 do_writev+0x60/0xf0 ? inet_shutdown+0xac/0x110 SyS_writev+0x10/0x20 do_syscall_64+0x6f/0x140 ? prepare_exit_to_usermode+0x8b/0xa0 entry_SYSCALL_64_after_hwframe+0x3d/0xa2 RIP: 0033:0x3135ce0c57 RSP: 002b:00007f5916de4b00 EFLAGS: 00000293 ORIG_RAX: 0000000000000014 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000003135ce0c57 RDX: 0000000000000002 RSI: 00007f5916de4b90 RDI: 000000000000606f RBP: 0000000000000000 R08: 0000000000000000 R09: 00007f5916de8c38 R10: 0000000000000000 R11: 0000000000000293 R12: 00000000000464cc R13: 00007f5916de8c30 R14: 00007f58d8bef080 R15: 0000000000000002 Code: 48 8b 97 60 01 00 00 4c 8d 97 58 01 00 00 41 b9 00 00 00 00 41 89 f3 4c 39 d2 49 0f 44 d1 41 81 e3 00 80 00 00 0f 85 b0 00 00 00 <80> 4a 38 08 44 8b 8f 74 06 00 00 44 89 8f 7c 06 00 00 83 e6 01 RIP: tcp_push+0x48/0x120 RSP: ffffc9000e947a88 CR2: 0000000000000038 ---[ end trace 8d545c2e93515549 ]--- There is other scenario which found in stable 4.4: Allocated: [] __alloc_skb+0xe6/0x600 net/core/skbuff.c:218 [] alloc_skb_fclone include/linux/skbuff.h:856 [inline] [] sk_stream_alloc_skb+0xa3/0x5d0 net/ipv4/tcp.c:833 [] tcp_sendmsg+0xd34/0x2b00 net/ipv4/tcp.c:1178 [] inet_sendmsg+0x203/0x4d0 net/ipv4/af_inet.c:755 Freed: [] __kfree_skb+0x1d/0x20 net/core/skbuff.c:676 [] sk_wmem_free_skb include/net/sock.h:1447 [inline] [] tcp_write_queue_purge include/net/tcp.h:1460 [inline] [] tcp_connect_init net/ipv4/tcp_output.c:3122 [inline] [] tcp_connect+0xb24/0x30c0 net/ipv4/tcp_output.c:3261 [] tcp_v4_connect+0xf31/0x1890 net/ipv4/tcp_ipv4.c:246 BUG: KASAN: use-after-free in tcp_skb_pcount include/net/tcp.h:796 [inline] BUG: KASAN: use-after-free in tcp_init_tso_segs net/ipv4/tcp_output.c:1619 [inline] BUG: KASAN: use-after-free in tcp_write_xmit+0x3fc2/0x4cb0 net/ipv4/tcp_output.c:2056 [] kasan_report.cold.7+0x175/0x2f7 mm/kasan/report.c:408 [] __asan_report_load2_noabort+0x14/0x20 mm/kasan/report.c:427 [] tcp_skb_pcount include/net/tcp.h:796 [inline] [] tcp_init_tso_segs net/ipv4/tcp_output.c:1619 [inline] [] tcp_write_xmit+0x3fc2/0x4cb0 net/ipv4/tcp_output.c:2056 [] __tcp_push_pending_frames+0xa0/0x290 net/ipv4/tcp_output.c:2307 stable 4.4 and stable 4.9 don't have the commit abb4a8b870b5 ("tcp: purge write queue upon RST") which is referred in dbbf2d1e4077, in tcp_connect_init, it calls tcp_write_queue_purge, and does not reset sk_send_head, then UAF. stable 4.14 have the commit abb4a8b870b5 ("tcp: purge write queue upon RST"), in tcp_reset, it calls tcp_write_queue_purge(sk), and does not reset sk_send_head, then UAF. So this patch can be used to fix stable 4.4 and 4.9. Fixes: a27fd7a8ed38 (tcp: purge write queue upon RST) Reported-by: Timofey Titovets Reported-by: Yongjian Xu Signed-off-by: Eric Dumazet Signed-off-by: Soheil Hassas Yeganeh Tested-by: Yongjian Xu Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman Signed-off-by: Mao Wenan Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

access: avoid the RCU grace period for the temporary subjective credentials

2019-08-04T07:33:43Z

commit d7852fbd0f0423937fa287a598bfde188bb68c22 upstream. It turns out that 'access()' (and 'faccessat()') can cause a lot of RCU work because it installs a temporary credential that gets allocated and freed for each system call. The allocation and freeing overhead is mostly benign, but because credentials can be accessed under the RCU read lock, the freeing involves a RCU grace period. Which is not a huge deal normally, but if you have a lot of access() calls, this causes a fair amount of seconday damage: instead of having a nice alloc/free patterns that hits in hot per-CPU slab caches, you have all those delayed free's, and on big machines with hundreds of cores, the RCU overhead can end up being enormous. But it turns out that all of this is entirely unnecessary. Exactly because access() only installs the credential as the thread-local subjective credential, the temporary cred pointer doesn't actually need to be RCU free'd at all. Once we're done using it, we can just free it synchronously and avoid all the RCU overhead. So add a 'non_rcu' flag to 'struct cred', which can be set by users that know they only use it in non-RCU context (there are other potential users for this). We can make it a union with the rcu freeing list head that we need for the RCU case, so this doesn't need any extra storage. Note that this also makes 'get_current_cred()' clear the new non_rcu flag, in case we have filesystems that take a long-term reference to the cred and then expect the RCU delayed freeing afterwards. It's not entirely clear that this is required, but it makes for clear semantics: the subjective cred remains non-RCU as long as you only access it synchronously using the thread-local accessors, but you _can_ use it as a generic cred if you want to. It is possible that we should just remove the whole RCU markings for ->cred entirely. Only ->real_cred is really supposed to be accessed through RCU, and the long-term cred copies that nfs uses might want to explicitly re-enable RCU freeing if required, rather than have get_current_cred() do it implicitly. But this is a "minimal semantic changes" change for the immediate problem. Acked-by: Peter Zijlstra (Intel) Acked-by: Eric Dumazet Acked-by: Paul E. McKenney Cc: Oleg Nesterov Cc: Jan Glauber Cc: Jiri Kosina Cc: Jayachandran Chandrasekharan Nair Cc: Greg KH Cc: Kees Cook Cc: David Howells Cc: Miklos Szeredi Cc: Al Viro Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

user/sven/linux.git/include, branch v4.9.188

include/linux/module.h: copy __init/__exit attrs to init/cleanup_module

Backport minimal compiler_attributes.h to support GCC 9

coredump: fix race condition between collapse_huge_page() and core dumping

coredump: fix race condition between mmget_not_zero()/get_task_mm() and core dumping

uapi linux/coda_psdev.h: move upc_req definition from uapi to kernel side headers

coda: fix build using bare-metal toolchain

ACPI: fix false-positive -Wuninitialized warning

sched/fair: Don't free p->numa_faults with concurrent readers

tcp: reset sk_send_head in tcp_write_queue_purge

access: avoid the RCU grace period for the temporary subjective credentials

include/linux/module.h: copy init/exit attrs to init/cleanup_module