The patch titled
Subject: coredump: make coredump_wait wait for mmap_sem for write killable
has been removed from the -mm tree. Its filename was
coredump-make-coredump_wait-wait-for-mmap_sem-for-write-killable.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Michal Hocko <mhocko@xxxxxxxx>
Subject: 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@xxxxxxxx>
Acked-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/coredump.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff -puN fs/coredump.c~coredump-make-coredump_wait-wait-for-mmap_sem-for-write-killable fs/coredump.c
--- a/fs/coredump.c~coredump-make-coredump_wait-wait-for-mmap_sem-for-write-killable
+++ a/fs/coredump.c
@@ -413,7 +413,9 @@ static int coredump_wait(int exit_code,
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);
_
Patches currently in -mm which might be from mhocko@xxxxxxxx are
oom_reaper-close-race-with-exiting-task.patch
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