Commit 4136c26b authored by Michal Hocko's avatar Michal Hocko Committed by Linus Torvalds
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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
Signed-off-by: default avatarMichal Hocko <>
Acked-by: default avatarOleg Nesterov <>
Acked-by: default avatarVlastimil Babka <>
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent 69048176
......@@ -413,7 +413,9 @@ static int coredump_wait(int exit_code, struct core_state *core_state)
core_state->dumper.task = tsk;
core_state-> = NULL;
if (down_write_killable(&mm->mmap_sem))
return -EINTR;
if (!mm->core_state)
core_waiters = zap_threads(tsk, mm, core_state, exit_code);
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