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| author | Rik van Riel <riel@redhat.com> | 2014-09-12 09:12:15 -0400 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2014-09-19 12:35:17 +0200 |
| commit | 9c368b5b6eccce1cbd7f68142106b3b4ddb1c5b5 (patch) | |
| tree | 2d74483c5bccdf6f513a763971fe419191afffd8 /arch/um | |
| parent | ef8ac06359ddf95431cf6bb04ad2b36fff562328 (diff) | |
| download | talos-obmc-linux-9c368b5b6eccce1cbd7f68142106b3b4ddb1c5b5.tar.gz talos-obmc-linux-9c368b5b6eccce1cbd7f68142106b3b4ddb1c5b5.zip | |
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 'arch/um')
0 files changed, 0 insertions, 0 deletions
