user/sven/linux.git/kernel, branch v4.19.102

cgroup: Prevent double killing of css when enabling threaded cgroup

2020-02-05T14:43:39Z

commit 3bc0bb36fa30e95ca829e9cf480e1ef7f7638333 upstream. The test_cgcore_no_internal_process_constraint_on_threads selftest when running with subsystem controlling noise triggers two warnings: > [ 597.443115] WARNING: CPU: 1 PID: 28167 at kernel/cgroup/cgroup.c:3131 cgroup_apply_control_enable+0xe0/0x3f0 > [ 597.443413] WARNING: CPU: 1 PID: 28167 at kernel/cgroup/cgroup.c:3177 cgroup_apply_control_disable+0xa6/0x160 Both stem from a call to cgroup_type_write. The first warning was also triggered by syzkaller. When we're switching cgroup to threaded mode shortly after a subsystem was disabled on it, we can see the respective subsystem css dying there. The warning in cgroup_apply_control_enable is harmless in this case since we're not adding new subsys anyway. The warning in cgroup_apply_control_disable indicates an attempt to kill css of recently disabled subsystem repeatedly. The commit prevents these situations by making cgroup_type_write wait for all dying csses to go away before re-applying subtree controls. When at it, the locations of WARN_ON_ONCE calls are moved so that warning is triggered only when we are about to misuse the dying css. Reported-by: syzbot+5493b2a54d31d6aea629@syzkaller.appspotmail.com Reported-by: Christian Brauner Signed-off-by: Michal Koutný Signed-off-by: Tejun Heo Signed-off-by: Greg Kroah-Hartman

sched/fair: Fix insertion in rq->leaf_cfs_rq_list

2020-02-01T09:37:10Z

commit f6783319737f28e4436a69611853a5a098cbe974 upstream. Sargun reported a crash: "I picked up c40f7d74c741a907cfaeb73a7697081881c497d0 sched/fair: Fix infinite loop in update_blocked_averages() by reverting a9e7f6544b9c and put it on top of 4.19.13. In addition to this, I uninlined list_add_leaf_cfs_rq for debugging. This revealed a new bug that we didn't get to because we kept getting crashes from the previous issue. When we are running with cgroups that are rapidly changing, with CFS bandwidth control, and in addition using the cpusets cgroup, we see this crash. Specifically, it seems to occur with cgroups that are throttled and we change the allowed cpuset." The algorithm used to order cfs_rq in rq->leaf_cfs_rq_list assumes that it will walk down to root the 1st time a cfs_rq is used and we will finish to add either a cfs_rq without parent or a cfs_rq with a parent that is already on the list. But this is not always true in presence of throttling. Because a cfs_rq can be throttled even if it has never been used but other CPUs of the cgroup have already used all the bandwdith, we are not sure to go down to the root and add all cfs_rq in the list. Ensure that all cfs_rq will be added in the list even if they are throttled. [ mingo: Fix !CGROUPS build. ] Reported-by: Sargun Dhillon Signed-off-by: Vincent Guittot Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: tj@kernel.org Fixes: 9c2791f936ef ("Fix hierarchical order in rq->leaf_cfs_rq_list") Link: https://lkml.kernel.org/r/1548825767-10799-1-git-send-email-vincent.guittot@linaro.org Signed-off-by: Ingo Molnar Cc: Janne Huttunen Signed-off-by: Greg Kroah-Hartman

sched/fair: Add tmp_alone_branch assertion

2020-02-01T09:37:10Z

commit 5d299eabea5a251fbf66e8277704b874bbba92dc upstream. The magic in list_add_leaf_cfs_rq() requires that at the end of enqueue_task_fair(): rq->tmp_alone_branch == &rq->lead_cfs_rq_list If this is violated, list integrity is compromised for list entries and the tmp_alone_branch pointer might dangle. Also, reflow list_add_leaf_cfs_rq() while there. This looses one indentation level and generates a form that's convenient for the next patch. Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Signed-off-by: Ingo Molnar Cc: Janne Huttunen Signed-off-by: Greg Kroah-Hartman

mm/memory_hotplug: shrink zones when offlining memory

2020-01-29T15:43:27Z

commit feee6b2989165631b17ac6d4ccdbf6759254e85a upstream. -- snip -- - Missing arm64 hot(un)plug support - Missing some vmem_altmap_offset() cleanups - Missing sub-section hotadd support - Missing unification of mm/hmm.c and kernel/memremap.c -- snip -- We currently try to shrink a single zone when removing memory. We use the zone of the first page of the memory we are removing. If that memmap was never initialized (e.g., memory was never onlined), we will read garbage and can trigger kernel BUGs (due to a stale pointer): BUG: unable to handle page fault for address: 000000000000353d #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 0 P4D 0 Oops: 0002 [#1] SMP PTI CPU: 1 PID: 7 Comm: kworker/u8:0 Not tainted 5.3.0-rc5-next-20190820+ #317 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.1-0-ga5cab58e9a3f-prebuilt.qemu.4 Workqueue: kacpi_hotplug acpi_hotplug_work_fn RIP: 0010:clear_zone_contiguous+0x5/0x10 Code: 48 89 c6 48 89 c3 e8 2a fe ff ff 48 85 c0 75 cf 5b 5d c3 c6 85 fd 05 00 00 01 5b 5d c3 0f 1f 840 RSP: 0018:ffffad2400043c98 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000200000000 RCX: 0000000000000000 RDX: 0000000000200000 RSI: 0000000000140000 RDI: 0000000000002f40 RBP: 0000000140000000 R08: 0000000000000000 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000140000 R13: 0000000000140000 R14: 0000000000002f40 R15: ffff9e3e7aff3680 FS: 0000000000000000(0000) GS:ffff9e3e7bb00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000000353d CR3: 0000000058610000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __remove_pages+0x4b/0x640 arch_remove_memory+0x63/0x8d try_remove_memory+0xdb/0x130 __remove_memory+0xa/0x11 acpi_memory_device_remove+0x70/0x100 acpi_bus_trim+0x55/0x90 acpi_device_hotplug+0x227/0x3a0 acpi_hotplug_work_fn+0x1a/0x30 process_one_work+0x221/0x550 worker_thread+0x50/0x3b0 kthread+0x105/0x140 ret_from_fork+0x3a/0x50 Modules linked in: CR2: 000000000000353d Instead, shrink the zones when offlining memory or when onlining failed. Introduce and use remove_pfn_range_from_zone(() for that. We now properly shrink the zones, even if we have DIMMs whereby - Some memory blocks fall into no zone (never onlined) - Some memory blocks fall into multiple zones (offlined+re-onlined) - Multiple memory blocks that fall into different zones Drop the zone parameter (with a potential dubious value) from __remove_pages() and __remove_section(). Link: http://lkml.kernel.org/r/20191006085646.5768-6-david@redhat.com Fixes: f1dd2cd13c4b ("mm, memory_hotplug: do not associate hotadded memory to zones until online") [visible after d0dc12e86b319] Signed-off-by: David Hildenbrand Reviewed-by: Oscar Salvador Cc: Michal Hocko Cc: "Matthew Wilcox (Oracle)" Cc: "Aneesh Kumar K.V" Cc: Pavel Tatashin Cc: Greg Kroah-Hartman Cc: Dan Williams Cc: Logan Gunthorpe Cc: [5.0+] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: David Hildenbrand Signed-off-by: Greg Kroah-Hartman

mm/memunmap: don't access uninitialized memmap in memunmap_pages()

2020-01-29T15:43:27Z

commit 77e080e7680e1e615587352f70c87b9e98126d03 upstream. -- snip -- - Missing mm/hmm.c and kernel/memremap.c unification. -- hmm code does not need fixes (no altmap) - Missing 7cc7867fb061 ("mm/devm_memremap_pages: enable sub-section remap") -- snip -- Patch series "mm/memory_hotplug: Shrink zones before removing memory", v6. This series fixes the access of uninitialized memmaps when shrinking zones/nodes and when removing memory. Also, it contains all fixes for crashes that can be triggered when removing certain namespace using memunmap_pages() - ZONE_DEVICE, reported by Aneesh. We stop trying to shrink ZONE_DEVICE, as it's buggy, fixing it would be more involved (we don't have SECTION_IS_ONLINE as an indicator), and shrinking is only of limited use (set_zone_contiguous() cannot detect the ZONE_DEVICE as contiguous). We continue shrinking !ZONE_DEVICE zones, however, I reduced the amount of code to a minimum. Shrinking is especially necessary to keep zone->contiguous set where possible, especially, on memory unplug of DIMMs at zone boundaries. -------------------------------------------------------------------------- Zones are now properly shrunk when offlining memory blocks or when onlining failed. This allows to properly shrink zones on memory unplug even if the separate memory blocks of a DIMM were onlined to different zones or re-onlined to a different zone after offlining. Example: :/# cat /proc/zoneinfo Node 1, zone Movable spanned 0 present 0 managed 0 :/# echo "online_movable" > /sys/devices/system/memory/memory41/state :/# echo "online_movable" > /sys/devices/system/memory/memory43/state :/# cat /proc/zoneinfo Node 1, zone Movable spanned 98304 present 65536 managed 65536 :/# echo 0 > /sys/devices/system/memory/memory43/online :/# cat /proc/zoneinfo Node 1, zone Movable spanned 32768 present 32768 managed 32768 :/# echo 0 > /sys/devices/system/memory/memory41/online :/# cat /proc/zoneinfo Node 1, zone Movable spanned 0 present 0 managed 0 This patch (of 10): With an altmap, the memmap falling into the reserved altmap space are not initialized and, therefore, contain a garbage NID and a garbage zone. Make sure to read the NID/zone from a memmap that was initialized. This fixes a kernel crash that is observed when destroying a namespace: kernel BUG at include/linux/mm.h:1107! cpu 0x1: Vector: 700 (Program Check) at [c000000274087890] pc: c0000000004b9728: memunmap_pages+0x238/0x340 lr: c0000000004b9724: memunmap_pages+0x234/0x340 ... pid = 3669, comm = ndctl kernel BUG at include/linux/mm.h:1107! devm_action_release+0x30/0x50 release_nodes+0x268/0x2d0 device_release_driver_internal+0x174/0x240 unbind_store+0x13c/0x190 drv_attr_store+0x44/0x60 sysfs_kf_write+0x70/0xa0 kernfs_fop_write+0x1ac/0x290 __vfs_write+0x3c/0x70 vfs_write+0xe4/0x200 ksys_write+0x7c/0x140 system_call+0x5c/0x68 The "page_zone(pfn_to_page(pfn)" was introduced by 69324b8f4833 ("mm, devm_memremap_pages: add MEMORY_DEVICE_PRIVATE support"), however, I think we will never have driver reserved memory with MEMORY_DEVICE_PRIVATE (no altmap AFAIKS). [david@redhat.com: minimze code changes, rephrase description] Link: http://lkml.kernel.org/r/20191006085646.5768-2-david@redhat.com Fixes: 2c2a5af6fed2 ("mm, memory_hotplug: add nid parameter to arch_remove_memory") Signed-off-by: Aneesh Kumar K.V Signed-off-by: David Hildenbrand Cc: Dan Williams Cc: Jason Gunthorpe Cc: Logan Gunthorpe Cc: Ira Weiny Cc: Damian Tometzki Cc: Alexander Duyck Cc: Alexander Potapenko Cc: Andy Lutomirski Cc: Anshuman Khandual Cc: Benjamin Herrenschmidt Cc: Borislav Petkov Cc: Catalin Marinas Cc: Christian Borntraeger Cc: Christophe Leroy Cc: Dave Hansen Cc: Fenghua Yu Cc: Gerald Schaefer Cc: Greg Kroah-Hartman Cc: Halil Pasic Cc: Heiko Carstens Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Jun Yao Cc: Mark Rutland Cc: Masahiro Yamada Cc: "Matthew Wilcox (Oracle)" Cc: Mel Gorman Cc: Michael Ellerman Cc: Michal Hocko Cc: Mike Rapoport Cc: Oscar Salvador Cc: Pankaj Gupta Cc: Paul Mackerras Cc: Pavel Tatashin Cc: Pavel Tatashin Cc: Peter Zijlstra Cc: Qian Cai Cc: Rich Felker Cc: Robin Murphy Cc: Steve Capper Cc: Thomas Gleixner Cc: Tom Lendacky Cc: Tony Luck Cc: Vasily Gorbik Cc: Vlastimil Babka Cc: Wei Yang Cc: Wei Yang Cc: Will Deacon Cc: Yoshinori Sato Cc: Yu Zhao Cc: [5.0+] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: David Hildenbrand Signed-off-by: Greg Kroah-Hartman

mm, memory_hotplug: add nid parameter to arch_remove_memory

2020-01-29T15:43:25Z

commit 2c2a5af6fed20cf74401c9d64319c76c5ff81309 upstream. -- snip -- Missing unification of mm/hmm.c and kernel/memremap.c -- snip -- Patch series "Do not touch pages in hot-remove path", v2. This patchset aims for two things: 1) A better definition about offline and hot-remove stage 2) Solving bugs where we can access non-initialized pages during hot-remove operations [2] [3]. This is achieved by moving all page/zone handling to the offline stage, so we do not need to access pages when hot-removing memory. [1] https://patchwork.kernel.org/cover/10691415/ [2] https://patchwork.kernel.org/patch/10547445/ [3] https://www.spinics.net/lists/linux-mm/msg161316.html This patch (of 5): This is a preparation for the following-up patches. The idea of passing the nid is that it will allow us to get rid of the zone parameter afterwards. Link: http://lkml.kernel.org/r/20181127162005.15833-2-osalvador@suse.de Signed-off-by: Oscar Salvador Reviewed-by: David Hildenbrand Reviewed-by: Pavel Tatashin Cc: Michal Hocko Cc: Dan Williams Cc: Jerome Glisse Cc: Jonathan Cameron Cc: "Rafael J. Wysocki" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: David Hildenbrand Signed-off-by: Greg Kroah-Hartman

tracing: Fix histogram code when expression has same var as value

2020-01-29T15:43:23Z

commit 8bcebc77e85f3d7536f96845a0fe94b1dddb6af0 upstream. While working on a tool to convert SQL syntex into the histogram language of the kernel, I discovered the following bug: # echo 'first u64 start_time u64 end_time pid_t pid u64 delta' >> synthetic_events # echo 'hist:keys=pid:start=common_timestamp' > events/sched/sched_waking/trigger # echo 'hist:keys=next_pid:delta=common_timestamp-$start,start2=$start:onmatch(sched.sched_waking).trace(first,$start2,common_timestamp,next_pid,$delta)' > events/sched/sched_switch/trigger Would not display any histograms in the sched_switch histogram side. But if I were to swap the location of "delta=common_timestamp-$start" with "start2=$start" Such that the last line had: # echo 'hist:keys=next_pid:start2=$start,delta=common_timestamp-$start:onmatch(sched.sched_waking).trace(first,$start2,common_timestamp,next_pid,$delta)' > events/sched/sched_switch/trigger The histogram works as expected. What I found out is that the expressions clear out the value once it is resolved. As the variables are resolved in the order listed, when processing: delta=common_timestamp-$start The $start is cleared. When it gets to "start2=$start", it errors out with "unresolved symbol" (which is silent as this happens at the location of the trace), and the histogram is dropped. When processing the histogram for variable references, instead of adding a new reference for a variable used twice, use the same reference. That way, not only is it more efficient, but the order will no longer matter in processing of the variables. From Tom Zanussi: "Just to clarify some more about what the problem was is that without your patch, we would have two separate references to the same variable, and during resolve_var_refs(), they'd both want to be resolved separately, so in this case, since the first reference to start wasn't part of an expression, it wouldn't get the read-once flag set, so would be read normally, and then the second reference would do the read-once read and also be read but using read-once. So everything worked and you didn't see a problem: from: start2=$start,delta=common_timestamp-$start In the second case, when you switched them around, the first reference would be resolved by doing the read-once, and following that the second reference would try to resolve and see that the variable had already been read, so failed as unset, which caused it to short-circuit out and not do the trigger action to generate the synthetic event: to: delta=common_timestamp-$start,start2=$start With your patch, we only have the single resolution which happens correctly the one time it's resolved, so this can't happen." Link: https://lore.kernel.org/r/20200116154216.58ca08eb@gandalf.local.home Cc: stable@vger.kernel.org Fixes: 067fe038e70f6 ("tracing: Add variable reference handling to hist triggers") Reviewed-by: Tom Zanuss Tested-by: Tom Zanussi Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Greg Kroah-Hartman

tracing: Remove open-coding of hist trigger var_ref management

2020-01-29T15:43:23Z

commit de40f033d4e84e843d6a12266e3869015ea9097c upstream. Have create_var_ref() manage the hist trigger's var_ref list, rather than having similar code doing it in multiple places. This cleans up the code and makes sure var_refs are always accounted properly. Also, document the var_ref-related functions to make what their purpose clearer. Link: http://lkml.kernel.org/r/05ddae93ff514e66fc03897d6665231892939913.1545161087.git.tom.zanussi@linux.intel.com Acked-by: Namhyung Kim Reviewed-by: Masami Hiramatsu Signed-off-by: Tom Zanussi Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Greg Kroah-Hartman

tracing: Use hist trigger's var_ref array to destroy var_refs

2020-01-29T15:43:23Z

commit 656fe2ba85e81d00e4447bf77b8da2be3c47acb2 upstream. Since every var ref for a trigger has an entry in the var_ref[] array, use that to destroy the var_refs, instead of piecemeal via the field expressions. This allows us to avoid having to keep and treat differently separate lists for the action-related references, which future patches will remove. Link: http://lkml.kernel.org/r/fad1a164f0e257c158e70d6eadbf6c586e04b2a2.1545161087.git.tom.zanussi@linux.intel.com Acked-by: Namhyung Kim Reviewed-by: Masami Hiramatsu Signed-off-by: Tom Zanussi Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Greg Kroah-Hartman

tracing: trigger: Replace unneeded RCU-list traversals

2020-01-29T15:43:18Z

commit aeed8aa3874dc15b9d82a6fe796fd7cfbb684448 upstream. With CONFIG_PROVE_RCU_LIST, I had many suspicious RCU warnings when I ran ftracetest trigger testcases. ----- # dmesg -c > /dev/null # ./ftracetest test.d/trigger ... # dmesg | grep "RCU-list traversed" | cut -f 2 -d ] | cut -f 2 -d " " kernel/trace/trace_events_hist.c:6070 kernel/trace/trace_events_hist.c:1760 kernel/trace/trace_events_hist.c:5911 kernel/trace/trace_events_trigger.c:504 kernel/trace/trace_events_hist.c:1810 kernel/trace/trace_events_hist.c:3158 kernel/trace/trace_events_hist.c:3105 kernel/trace/trace_events_hist.c:5518 kernel/trace/trace_events_hist.c:5998 kernel/trace/trace_events_hist.c:6019 kernel/trace/trace_events_hist.c:6044 kernel/trace/trace_events_trigger.c:1500 kernel/trace/trace_events_trigger.c:1540 kernel/trace/trace_events_trigger.c:539 kernel/trace/trace_events_trigger.c:584 ----- I investigated those warnings and found that the RCU-list traversals in event trigger and hist didn't need to use RCU version because those were called only under event_mutex. I also checked other RCU-list traversals related to event trigger list, and found that most of them were called from event_hist_trigger_func() or hist_unregister_trigger() or register/unregister functions except for a few cases. Replace these unneeded RCU-list traversals with normal list traversal macro and lockdep_assert_held() to check the event_mutex is held. Link: http://lkml.kernel.org/r/157680910305.11685.15110237954275915782.stgit@devnote2 Cc: stable@vger.kernel.org Fixes: 30350d65ac567 ("tracing: Add variable support to hist triggers") Reviewed-by: Tom Zanussi Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Greg Kroah-Hartman