swh:1:snp:49cd9498d6cccc5e78252c27dcb645bcf7bf0c91
Revision 74070542099c66d87aebeacd7b54dc0e8b6a73f9 authored by Michal Hocko on 24 June 2016, 21:50:16 UTC, committed by Linus Torvalds on 25 June 2016, 00:23:52 UTC
Tetsuo has reported the following potential oom_killer_disable vs. oom_reaper race: (1) freeze_processes() starts freezing user space threads. (2) Somebody (maybe a kenrel thread) calls out_of_memory(). (3) The OOM killer calls mark_oom_victim() on a user space thread P1 which is already in __refrigerator(). (4) oom_killer_disable() sets oom_killer_disabled = true. (5) P1 leaves __refrigerator() and enters do_exit(). (6) The OOM reaper calls exit_oom_victim(P1) before P1 can call exit_oom_victim(P1). (7) oom_killer_disable() returns while P1 not yet finished (8) P1 perform IO/interfere with the freezer. This situation is unfortunate. We cannot move oom_killer_disable after all the freezable kernel threads are frozen because the oom victim might depend on some of those kthreads to make a forward progress to exit so we could deadlock. It is also far from trivial to teach the oom_reaper to not call exit_oom_victim() because then we would lose a guarantee of the OOM killer and oom_killer_disable forward progress because exit_mm->mmput might block and never call exit_oom_victim. It seems the easiest way forward is to workaround this race by calling try_to_freeze_tasks again after oom_killer_disable. This will make sure that all the tasks are frozen or it bails out. Fixes: 449d777d7ad6 ("mm, oom_reaper: clear TIF_MEMDIE for all tasks queued for oom_reaper") Link: http://lkml.kernel.org/r/1466597634-16199-1-git-send-email-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Tip revision: 644e9524388a5dbc6d4f58c492ee9ef7bd4ddf4d authored by Linus Torvalds on 26 November 2022, 02:02:49 UTC
Merge tag 'for-v6.1-rc' of git://git.kernel.org/pub/scm/linux/kernel/git/sre/linux-power-supply
Merge tag 'for-v6.1-rc' of git://git.kernel.org/pub/scm/linux/kernel/git/sre/linux-power-supply
Tip revision: 644e952
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arch | ||
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certs | ||
crypto | ||
drivers | ||
firmware | ||
fs | ||
include | ||
init | ||
ipc | ||
kernel | ||
lib | ||
mm | ||
net | ||
samples | ||
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tools | ||
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.get_maintainer.ignore | -rw-r--r-- | 31 bytes |
.gitignore | -rw-r--r-- | 1.2 KB |
.mailmap | -rw-r--r-- | 6.4 KB |
COPYING | -rw-r--r-- | 18.3 KB |
CREDITS | -rw-r--r-- | 95.5 KB |
Kbuild | -rw-r--r-- | 2.8 KB |
Kconfig | -rw-r--r-- | 252 bytes |
MAINTAINERS | -rw-r--r-- | 353.7 KB |
Makefile | -rw-r--r-- | 56.0 KB |
README | -rw-r--r-- | 18.1 KB |
REPORTING-BUGS | -rw-r--r-- | 7.3 KB |
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