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From: Linus Torvalds <torvalds@linux-foundation.org>
To: "Robert Święcki" <robert@swiecki.net>
Cc: "Oleg Nesterov" <oleg@redhat.com>,
	"Américo Wang" <xiyou.wangcong@gmail.com>,
	linux-kernel@vger.kernel.org, "Hugh Dickins" <hughd@google.com>,
	"Miklos Szeredi" <mszeredi@suse.cz>
Subject: Re: Processes hang in an unkillable state
Date: Tue, 12 Apr 2011 13:22:39 -0700	[thread overview]
Message-ID: <BANLkTikoDELrA-RtA9BLm64mfoPgdADR0Q@mail.gmail.com> (raw)
In-Reply-To: <BANLkTimBegMUq2fX67o2YnoATWG-NDbKgA@mail.gmail.com>

On Tue, Apr 12, 2011 at 1:03 PM, Robert Święcki <robert@swiecki.net> wrote:
>>
>> Ok, applied Linus' patch and got the following (kdb dump in the attachment):
>>
>> It contains references to sys_mlock, but in another process/user that
>> oopsed (there are iknowthis and iknowthis2 processes running under
>> test and test2 users). I think I'll simply disable sys_madvise in the
>> fuzzer; and treat this oops as a separate issue.

This does seem to be something else.

It looks like some kind of live-lock situation between two processes
both doing madvise() and causing vmtruncate_range() calls.

Miklos wrote this patch for something bad in this area to serialize
concurrent unmap_mapping_range() calls in order to not restart forever
on vm_truncate_count. That got merged into 2.6.38, so it's there, but
I wonder if there is some case it misses.

                           Linus

  parent reply	other threads:[~2011-04-12 20:23 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-04-12 10:32 Robert Święcki
2011-04-12 12:44 ` Américo Wang
2011-04-12 13:03   ` Robert Święcki
2011-04-12 13:08     ` Robert Święcki
2011-04-12 18:28   ` Oleg Nesterov
2011-04-12 18:34     ` Robert Święcki
2011-04-12 19:20       ` Oleg Nesterov
     [not found]         ` <BANLkTimJgx_x=0bpBDWaUkJgZPYs3_iwsg@mail.gmail.com>
     [not found]           ` <BANLkTimBegMUq2fX67o2YnoATWG-NDbKgA@mail.gmail.com>
2011-04-12 20:22             ` Linus Torvalds [this message]
     [not found]               ` <BANLkTi=HyK+8DhJS3db0j2fefdOjwVMN3w@mail.gmail.com>
2011-04-12 21:46                 ` Linus Torvalds
2011-04-12 21:59                   ` Robert Święcki
2011-04-12 22:12                     ` Linus Torvalds
2011-04-12 22:16                       ` Robert Święcki
2011-04-12 22:18                         ` Linus Torvalds
2011-04-12 22:30                           ` Robert Święcki
2011-04-12 22:43                             ` Linus Torvalds
2011-04-13 12:19                               ` Robert Święcki
2011-04-12 19:07     ` [PATCH 0/1] Was: " Oleg Nesterov
2011-04-12 19:08       ` [PATCH 1/1] __mlock_vma_pages_range: stack_guard_page() case returns the wrong value Oleg Nesterov
2011-04-12 19:18         ` Robert Święcki

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