From: Sasha Levin <sasha.levin@oracle.com>
To: Andrew Morton <akpm@linux-foundation.org>,
Davidlohr Bueso <davidlohr@hp.com>
Cc: "linux-mm@kvack.org" <linux-mm@kvack.org>,
Michel Lespinasse <walken@google.com>,
Rik van Riel <riel@redhat.com>, Vlastimil Babka <vbabka@suse.cz>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: mm: mmap_sem lock assertion failure in __mlock_vma_pages_range
Date: Tue, 11 Mar 2014 16:35:55 -0400 [thread overview]
Message-ID: <531F73AB.5060402@oracle.com> (raw)
In-Reply-To: <20140311133051.bf5ca716ef189746ebcff431@linux-foundation.org>
On 03/11/2014 04:30 PM, Andrew Morton wrote:
> I worry about what happens if __get_user_pages decides to do
>
> if (ret & VM_FAULT_RETRY) {
> if (nonblocking)
> *nonblocking = 0;
> return i;
> }
>
> uh-oh, that just cleared __mm_populate()'s `locked' variable and we'll
> forget to undo mmap_sem. That won't explain this result, but it's a
> potential problem.
That's actually seems right because if 'ret & VM_FAULT_RETRY' is true it means that
lock_page_or_retry() was supposed to release mmap_sem for us.
Thanks,
Sasha
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next prev parent reply other threads:[~2014-03-11 20:36 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-11 19:39 mm: mmap_sem lock assertion failure in __mlock_vma_pages_range Sasha Levin
2014-03-11 20:07 ` Davidlohr Bueso
2014-03-11 20:12 ` Sasha Levin
2014-03-11 20:21 ` Davidlohr Bueso
2014-03-11 20:30 ` Andrew Morton
2014-03-11 20:35 ` Sasha Levin [this message]
2014-03-11 20:42 ` Davidlohr Bueso
2014-03-11 20:45 ` Sasha Levin
2014-03-11 20:47 ` Davidlohr Bueso
2014-03-11 20:57 ` Dave Jones
2014-03-11 21:02 ` Sasha Levin
2014-03-11 21:45 ` Davidlohr Bueso
2014-03-11 22:20 ` Sasha Levin
2014-03-13 19:00 ` Davidlohr Bueso
2014-03-13 20:57 ` Hugh Dickins
2014-03-14 16:14 ` Sasha Levin
2014-03-11 21:59 ` Michel Lespinasse
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