path: root/drivers/staging
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authorRik van Riel <riel@redhat.com>2014-09-12 09:12:15 -0400
committerIngo Molnar <mingo@kernel.org>2014-09-19 12:35:17 +0200
commit9c368b5b6eccce1cbd7f68142106b3b4ddb1c5b5 (patch)
tree2d74483c5bccdf6f513a763971fe419191afffd8 /drivers/staging
parentef8ac06359ddf95431cf6bb04ad2b36fff562328 (diff)
sched, time: Fix lock inversion in thread_group_cputime()
The sig->stats_lock nests inside the tasklist_lock and the sighand->siglock in __exit_signal and wait_task_zombie. However, both of those locks can be taken from irq context, which means we need to use the interrupt safe variant of read_seqbegin_or_lock. This blocks interrupts when the "lock" branch is taken (seq is odd), preventing the lock inversion. On the first (lockless) pass through the loop, irqs are not blocked. Reported-by: Stanislaw Gruszka <sgruszka@redhat.com> Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: prarit@redhat.com Cc: oleg@redhat.com Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1410527535-9814-3-git-send-email-riel@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'drivers/staging')
0 files changed, 0 insertions, 0 deletions

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