From: Maarten Lankhorst <maarten.lankhorst@canonical.com>
To: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: imirkin@alum.mit.edu, linux-kernel@vger.kernel.org,
daniel.vetter@ffwll.ch, robdclark@gmail.com,
a.p.zijlstra@chello.nl, mingo@kernel.org
Subject: Re: [3.11-rc1] CONFIG_DEBUG_MUTEXES=y using gcc 3.x makes unbootablekernel.
Date: Mon, 09 Sep 2013 14:07:40 +0200 [thread overview]
Message-ID: <522DBA0C.9030108@canonical.com> (raw)
In-Reply-To: <201309092056.GDH56750.OOMJtOHQVFFLSF@I-love.SAKURA.ne.jp>
Op 09-09-13 13:56, Tetsuo Handa schreef:
> Maarten Lankhorst wrote:
>> Almost correct. I meant passing it as parameter to __mutex_lock_common. Your version will still cause an extra pointless null check in the ww_mutex_lock case.
> Ah, I see.
> ----------
> >From 95f189eb37c25ddf8e48d5dfc2f9f1185c52b6a8 Mon Sep 17 00:00:00 2001
> From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
> Date: Mon, 9 Sep 2013 20:48:13 +0900
> Subject: [PATCH] mutex: Avoid gcc version dependent __builtin_constant_p() usage.
>
> Commit 040a0a37 "mutex: Add support for wound/wait style locks" used
> "!__builtin_constant_p(p == NULL)" but gcc 3.x cannot handle such expression
> correctly, leading to boot failure when built with CONFIG_DEBUG_MUTEXES=y.
>
> Fix it by explicitly passing a bool which tells whether p != NULL or not.
>
Yeah looks ok, did you run the selftests from CONFIG_DEBUG_LOCKING_API_SELFTESTS,
with/without CONFIG_PROVE_LOCKING and once more with DEBUG_MUTEXES also unset?
~Maarten
next prev parent reply other threads:[~2013-09-09 12:07 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-07 16:00 [3.11-rc1] CONFIG_DEBUG_MUTEXES=y using gcc 3.x makes unbootable kernel Tetsuo Handa
2013-09-08 4:32 ` Tetsuo Handa
2013-09-08 5:28 ` Ilia Mirkin
2013-09-08 7:24 ` Tetsuo Handa
2013-09-08 7:42 ` Ilia Mirkin
2013-09-08 8:11 ` Maarten Lankhorst
2013-09-08 11:53 ` [3.11-rc1] CONFIG_DEBUG_MUTEXES=y using gcc 3.x makes unbootablekernel Tetsuo Handa
2013-09-08 20:36 ` Maarten Lankhorst
2013-09-09 11:56 ` Tetsuo Handa
2013-09-09 12:07 ` Maarten Lankhorst [this message]
2013-09-09 13:22 ` Tetsuo Handa
2013-09-24 14:51 ` Tetsuo Handa
2013-09-09 12:58 ` Peter Zijlstra
2013-10-03 14:02 ` [PATCH for 3.12-rcX] mutex: Avoid gcc version dependent __builtin_constant_p() usage Tetsuo Handa
2013-10-16 20:20 ` Tetsuo Handa
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