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From: khalasa@piap.pl (Krzysztof Hałasa)
To: linux-arm-kernel@lists.infradead.org
Subject: v3.13-rc6+ regression (ARM board)
Date: Thu, 02 Jan 2014 11:02:44 +0100	[thread overview]
Message-ID: <m3txdmu2ez.fsf@t19.piap.pl> (raw)
In-Reply-To: <20131231104511.GA9688@1wt.eu> (Willy Tarreau's message of "Tue, 31 Dec 2013 11:45:11 +0100")

>> There seems to be a regression in v3.13-rc6+ (up to current tip =
>> 71ce176ee6ed1735b9a1160a5704a915d13849b1).
>>
>> Board is Gateworks Cambria, CPU Intel IXP435 ARM big endian, gcc 4.7.3.
>> The board boots correctly and works (shell mostly, and SSHD) for about
>> 50 seconds. After 52-54 seconds, it frozes dead without any console
>> (UART) output.
>>
>> Bisecting shows 5e30025a319910695f5010dc0fb53a23299da14d as the first
>> bad commit. Interestingly it's a merge:

Reverting 1ca7d67cf5d5a2aef26a8d9afd789006fa098347 on top of current tip
(9a0bb2966efbf30a71c128c3af63307d8b5f5fc0) fixes my issue.

What now?

1ca7d67cf5d5a2aef26a8d9afd789006fa098347:
    seqcount: Add lockdep functionality to seqcount/seqlock structures

    Currently seqlocks and seqcounts don't support lockdep.

    After running across a seqcount related deadlock in the timekeeping
    code, I used a less-refined and more focused variant of this patch
    to narrow down the cause of the issue.

    This is a first-pass attempt to properly enable lockdep functionality
    on seqlocks and seqcounts.

    Since seqcounts are used in the vdso gettimeofday code, I've provided
    non-lockdep accessors for those needs.

    I've also handled one case where there were nested seqlock writers
    and there may be more edge cases.

    Comments and feedback would be appreciated!
-- 
Krzysztof Halasa

Research Institute for Automation and Measurements PIAP
Al. Jerozolimskie 202, 02-486 Warsaw, Poland

  reply	other threads:[~2014-01-02 10:02 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-12-31 10:37 v3.13-rc6+ regression (ARM board) Krzysztof Hałasa
2013-12-31 10:45 ` Willy Tarreau
2014-01-02 10:02   ` Krzysztof Hałasa [this message]
2014-01-02 10:14     ` Uwe Kleine-König
2014-01-02 12:07       ` Krzysztof Hałasa
2014-01-02 19:38         ` Linus Torvalds
2014-01-02 20:03           ` John Stultz
2014-01-02 20:30             ` John Stultz
2014-01-02 20:42               ` Stephen Boyd
2014-01-02 20:52                 ` John Stultz
2014-01-02 20:43               ` Linus Torvalds
2014-01-02 21:34                 ` John Stultz
2014-01-02 21:54                   ` [PATCH] sched_clock: Disable seqlock lockdep usage in sched_clock John Stultz
2014-01-02 22:15                     ` Linus Torvalds
2014-01-02 22:21                       ` John Stultz
2014-01-02 23:11                         ` [PATCH 1/2] seqlock: Use raw_ prefix instead of _no_lockdep John Stultz
2014-01-02 23:11                           ` [PATCH 2/2] sched_clock: Disable seqlock lockdep usage in sched_clock John Stultz
2014-01-03  0:46                             ` Stephen Boyd
2014-01-03  6:05                             ` Krzysztof Hałasa
2014-01-03  0:46                           ` [PATCH 1/2] seqlock: Use raw_ prefix instead of _no_lockdep Stephen Boyd
2014-01-03  0:50                           ` Linus Torvalds
2014-01-04  0:28                             ` John Stultz
2014-01-06 10:10                               ` Peter Zijlstra
2014-01-03  6:01           ` v3.13-rc6+ regression (ARM board) Krzysztof Hałasa

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