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mm, fork: make dup_mmap wait for mmap_sem for write killable

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dup_mmap needs to lock current's mm mmap_sem for write.  If the waiting
task gets killed by the oom killer it would block oom_reaper from
asynchronous address space reclaim and reduce the chances of timely OOM
resolving.  Wait for the lock in the killable mode and return with EINTR
if the task got killed while waiting.

Signed-off-by: Michal Hocko <[email protected]>
Acked-by: Vlastimil Babka <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Konstantin Khlebnikov <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
This commit is contained in:
Michal Hocko authored and Linus Torvalds committed 2016-05-23 17:04:14 -07:00
1 parent 4e80153a60
commit 7c05126793
1 file changed
+5 -1
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kernel/fork.c
+5 -1
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@@ -414,7 +414,10 @@ static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
unsigned long charge;
uprobe_start_dup_mmap();
down_write(&oldmm->mmap_sem);
if (down_write_killable(&oldmm->mmap_sem)) {
retval = -EINTR;
goto fail_uprobe_end;
}
flush_cache_dup_mm(oldmm);
uprobe_dup_mmap(oldmm, mm);
/*
@@ -526,6 +529,7 @@ out:
up_write(&mm->mmap_sem);
flush_tlb_mm(oldmm);
up_write(&oldmm->mmap_sem);
fail_uprobe_end:
uprobe_end_dup_mmap();
return retval;
fail_nomem_anon_vma_fork: