Re: [PATCH 09/18] ipc, shm: make shmem attach/detach wait for mmap_sem killable

[Michal Hocko <mhocko@xxxxxxxxxx>]

On Tue 08-03-16 11:15:50, Davidlohr Bueso wrote:
> On Mon, 29 Feb 2016, Michal Hocko wrote:
> 
> >From: Michal Hocko <mhocko@xxxxxxxx>
> >
> >shmat and shmdt rely on 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.
> >
> >Cc: Davidlohr Bueso <dave@xxxxxxxxxxxx>
> >Cc: Hugh Dickins <hughd@xxxxxxxxxx>
> >Signed-off-by: Michal Hocko <mhocko@xxxxxxxx>
> 
> I have no objection to this perse, just one comment below.
> 
> Acked-by: Davidlohr Bueso <dave@xxxxxxxxxxxx>

Thanks!

[...]
> >-	down_write(&current->mm->mmap_sem);
> >+	if (down_write_killable(&current->mm->mmap_sem)) {
> >+		err = -EINVAL;
> >+		goto out_fput;
> >+	}
> 
> This should be EINTR, no?

Of course. Thanks for catching that.
-- 
Michal Hocko
SUSE Labs

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