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| author | Michal Hocko <mhocko@suse.com> | 2016-05-23 16:25:57 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-05-23 17:04:14 -0700 |
| commit | 4136c26b65d12d0c5ef58b7d30dc0aa2a11ed491 (patch) | |
| tree | acd092b56a44a3f87027e27ac93900ce4fa560b1 /fs/coredump.c | |
| parent | 69048176078adda4087a648c9b1812ddd800fad1 (diff) | |
| download | lwn-4136c26b65d12d0c5ef58b7d30dc0aa2a11ed491.tar.gz lwn-4136c26b65d12d0c5ef58b7d30dc0aa2a11ed491.zip | |
coredump: make coredump_wait wait for mmap_sem for write killable
coredump_wait waits for mmap_sem for write currently which can prevent
oom_reaper to reclaim the oom victims address space asynchronously
because that requires mmap_sem for read. This might happen if the oom
victim is multi threaded and some thread(s) is holding mmap_sem for read
(e.g. page fault) and it is stuck in the page allocator while other
thread(s) reached coredump_wait already.
This patch simply uses down_write_killable and bails out with EINTR if
the lock got interrupted by the fatal signal. do_coredump will return
right away and do_group_exit will take care to zap the whole thread
group.
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/coredump.c')
| -rw-r--r-- | fs/coredump.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/fs/coredump.c b/fs/coredump.c index 492c2db25dc9..38a7ab87e10a 100644 --- a/fs/coredump.c +++ b/fs/coredump.c @@ -413,7 +413,9 @@ static int coredump_wait(int exit_code, struct core_state *core_state) core_state->dumper.task = tsk; core_state->dumper.next = NULL; - down_write(&mm->mmap_sem); + if (down_write_killable(&mm->mmap_sem)) + return -EINTR; + if (!mm->core_state) core_waiters = zap_threads(tsk, mm, core_state, exit_code); up_write(&mm->mmap_sem); |