From 7c051267931a9be9c6620cc17b362bc6ee6dedc8 Mon Sep 17 00:00:00 2001 From: Michal Hocko Date: Mon, 23 May 2016 16:25:48 -0700 Subject: [PATCH] mm, fork: make dup_mmap wait for mmap_sem for write killable 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 Acked-by: Vlastimil Babka Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Oleg Nesterov Cc: Konstantin Khlebnikov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/fork.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/kernel/fork.c b/kernel/fork.c index e67d7b7..47887bb 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -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: -- 2.7.4