From: Michal Hocko <mhocko@kernel.org>
To: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>,
Vegard Nossum <vegard.nossum@oracle.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Rik van Riel <riel@redhat.com>,
Matthew Wilcox <mawilcox@microsoft.com>,
Peter Zijlstra <peterz@infradead.org>,
Andrew Morton <akpm@linux-foundation.org>,
Al Viro <viro@zeniv.linux.org.uk>, Ingo Molnar <mingo@kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: crash during oom reaper
Date: Sun, 18 Dec 2016 17:06:08 +0100 [thread overview]
Message-ID: <20161218160608.GA8440@dhcp22.suse.cz> (raw)
In-Reply-To: <7918aa6b-8517-956b-5258-616ef1df6338@I-love.SAKURA.ne.jp>
On Sun 18-12-16 22:47:07, Tetsuo Handa wrote:
> On 2016/12/16 22:14, Michal Hocko wrote:
[...]
> > I would have to rememeber all the details. This is mostly off-topic for
> > this particular thread so I think it would be better if you could send a
> > full patch separatelly and we can discuss it there?
> >
>
> zap_page_range() calls mmu_notifier_invalidate_range_start().
> mmu_notifier_invalidate_range_start() calls __mmu_notifier_invalidate_range_start().
> __mmu_notifier_invalidate_range_start() calls srcu_read_lock()/srcu_read_unlock().
> This means that zap_page_range() might sleep.
>
> I don't know what individual notifier will do, but for example
>
> static const struct mmu_notifier_ops i915_gem_userptr_notifier = {
> .invalidate_range_start = i915_gem_userptr_mn_invalidate_range_start,
> };
>
> i915_gem_userptr_mn_invalidate_range_start() calls flush_workqueue()
> which means that we can OOM livelock if work item involves memory allocation.
> Some of other notifiers call mutex_lock()/mutex_unlock().
>
> Even if none of currently in-tree notifier users are blocked on memory
> allocation, I think it is not guaranteed that future changes/users won't be
> blocked on memory allocation.
Kirill has sent this as a separate patchset [1]. Could you follow up on
that there please?
http://lkml.kernel.org/r/20161216141556.75130-4-kirill.shutemov@linux.intel.com
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2016-12-18 16:06 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-16 8:21 [PATCH 1/4] mm: add new mmgrab() helper Vegard Nossum
2016-12-16 8:22 ` [PATCH 2/4] mm: add new mmget() helper Vegard Nossum
2016-12-16 9:26 ` Michal Hocko
2016-12-16 8:22 ` [PATCH 3/4] mm: use mmget_not_zero() helper Vegard Nossum
2016-12-16 9:27 ` Michal Hocko
2016-12-16 8:22 ` [PATCH 4/4] [RFC!] mm: 'struct mm_struct' reference counting debugging Vegard Nossum
2016-12-16 9:01 ` Michal Hocko
2016-12-16 9:43 ` Vegard Nossum
2016-12-16 10:11 ` crash during oom reaper (was: Re: [PATCH 4/4] [RFC!] mm: 'struct mm_struct' reference counting debugging) Michal Hocko
2016-12-16 10:44 ` Kirill A. Shutemov
2016-12-16 11:42 ` crash during oom reaper Michal Hocko
2016-12-16 12:12 ` Michal Hocko
2016-12-16 12:35 ` Kirill A. Shutemov
2016-12-16 12:56 ` Michal Hocko
2016-12-16 13:07 ` Kirill A. Shutemov
2016-12-16 13:14 ` Michal Hocko
2016-12-18 13:47 ` Tetsuo Handa
2016-12-18 16:06 ` Michal Hocko [this message]
2016-12-16 13:14 ` Vegard Nossum
2016-12-16 14:00 ` Michal Hocko
2016-12-16 14:25 ` Vegard Nossum
2016-12-16 14:32 ` Michal Hocko
2016-12-16 14:53 ` Vegard Nossum
2016-12-16 14:04 ` Vegard Nossum
2016-12-16 9:14 ` [PATCH 1/4] mm: add new mmgrab() helper Michal Hocko
2016-12-16 9:56 ` Peter Zijlstra
2016-12-16 10:19 ` Kirill A. Shutemov
2016-12-16 10:20 ` Vegard Nossum
2016-12-16 10:36 ` Michal Hocko
2016-12-16 11:14 ` Vegard Nossum
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