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| Started by | Michal Hocko <mhocko@kernel.org> |
|---|---|
| First post | 2016-02-29 14:30 +0100 |
| Last post | 2016-02-29 17:00 +0100 |
| Articles | 2 — 2 participants |
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[PATCH 11/18] coredump: make coredump_wait wait for mma_sem for write killable Michal Hocko <mhocko@kernel.org> - 2016-02-29 14:30 +0100
Re: [PATCH 11/18] coredump: make coredump_wait wait for mma_sem for write killable Oleg Nesterov <oleg@redhat.com> - 2016-02-29 17:00 +0100
| From | Michal Hocko <mhocko@kernel.org> |
|---|---|
| Date | 2016-02-29 14:30 +0100 |
| Subject | [PATCH 11/18] coredump: make coredump_wait wait for mma_sem for write killable |
| Message-ID | <r7w3D-3yu-5@gated-at.bofh.it> |
From: Michal Hocko <mhocko@suse.com> 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. Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Michal Hocko <mhocko@suse.com> --- fs/coredump.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/fs/coredump.c b/fs/coredump.c index 9ea87e9fdccf..6b8aa1629891 100644 --- a/fs/coredump.c +++ b/fs/coredump.c @@ -410,7 +410,9 @@ 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); -- 2.7.0
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| From | Oleg Nesterov <oleg@redhat.com> |
|---|---|
| Date | 2016-02-29 17:00 +0100 |
| Subject | Re: [PATCH 11/18] coredump: make coredump_wait wait for mma_sem for write killable |
| Message-ID | <r7yoO-4YQ-11@gated-at.bofh.it> |
| In reply to | #1345806 |
On 02/29, Michal Hocko wrote: > > --- a/fs/coredump.c > +++ b/fs/coredump.c > @@ -410,7 +410,9 @@ 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; > + ACK, thanks. Oleg.
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