From: Arnd Bergmann <arnd@arndb.de>
To: Josh Triplett <josh@joshtriplett.org>
Cc: Johannes Berg <johannes@sipsolutions.net>,
Dan Carpenter <error27@gmail.com>,
Jaroslav Kysela <perex@perex.cz>, Takashi Iwai <tiwai@suse.de>,
alsa-devel@alsa-project.org, kernel-janitors@vger.kernel.org,
linux-sparse@vger.kernel.org
Subject: Re: [patch 1/2] OSS: soundcard: locking bug in sound_ioctl()
Date: Tue, 12 Oct 2010 08:39:14 +0200 [thread overview]
Message-ID: <201010120839.15257.arnd@arndb.de> (raw)
In-Reply-To: <20101011222307.GA10570@feather>
On Tuesday 12 October 2010 00:23:08 Josh Triplett wrote:
> Assuming that the underlying function only returns zero/non-zero and
> that the actual return value doesn't matter, then you can use the
> __cond_lock macro from compiler.h for this:
>
> # define __cond_lock(x,c) ((c) ? ({ __acquire(x); 1; }) : 0)
>
The return from mutex_lock_{killable,interruptible} is an error
value, not true/false, so it actually matters. We know that the only
possible error that is currently returned is -EINTR though, so we
could do a similar trick and define another
#define __cond_mutex(x, c) ((!c) ? ({ __acquire(x); 0; }) : -EINTR)
My fear was that this would impact code generation.
Arnd
WARNING: multiple messages have this Message-ID (diff)
From: Arnd Bergmann <arnd@arndb.de>
To: Josh Triplett <josh@joshtriplett.org>
Cc: Johannes Berg <johannes@sipsolutions.net>,
Dan Carpenter <error27@gmail.com>,
Jaroslav Kysela <perex@perex.cz>, Takashi Iwai <tiwai@suse.de>,
alsa-devel@alsa-project.org, kernel-janitors@vger.kernel.org,
linux-sparse@vger.kernel.org
Subject: Re: [patch 1/2] OSS: soundcard: locking bug in sound_ioctl()
Date: Tue, 12 Oct 2010 06:39:14 +0000 [thread overview]
Message-ID: <201010120839.15257.arnd@arndb.de> (raw)
In-Reply-To: <20101011222307.GA10570@feather>
On Tuesday 12 October 2010 00:23:08 Josh Triplett wrote:
> Assuming that the underlying function only returns zero/non-zero and
> that the actual return value doesn't matter, then you can use the
> __cond_lock macro from compiler.h for this:
>
> # define __cond_lock(x,c) ((c) ? ({ __acquire(x); 1; }) : 0)
>
The return from mutex_lock_{killable,interruptible} is an error
value, not true/false, so it actually matters. We know that the only
possible error that is currently returned is -EINTR though, so we
could do a similar trick and define another
#define __cond_mutex(x, c) ((!c) ? ({ __acquire(x); 0; }) : -EINTR)
My fear was that this would impact code generation.
Arnd
next prev parent reply other threads:[~2010-10-12 6:39 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-10 17:33 [patch 1/2] OSS: soundcard: locking bug in sound_ioctl() Dan Carpenter
2010-10-10 17:33 ` Dan Carpenter
2010-10-10 18:39 ` Arnd Bergmann
2010-10-10 18:39 ` Arnd Bergmann
2010-10-11 8:13 ` Arnd Bergmann
2010-10-11 8:13 ` Arnd Bergmann
2010-10-11 8:50 ` Johannes Berg
2010-10-11 8:50 ` Johannes Berg
2010-10-11 10:50 ` Arnd Bergmann
2010-10-11 10:50 ` Arnd Bergmann
2010-10-11 10:52 ` Johannes Berg
2010-10-11 10:52 ` Johannes Berg
2010-10-11 18:54 ` Josh Triplett
2010-10-11 18:54 ` Josh Triplett
2010-10-11 20:42 ` Arnd Bergmann
2010-10-11 20:42 ` Arnd Bergmann
2010-10-11 22:23 ` Josh Triplett
2010-10-11 22:23 ` Josh Triplett
2010-10-12 6:39 ` Arnd Bergmann [this message]
2010-10-12 6:39 ` Arnd Bergmann
2010-10-12 6:43 ` Josh Triplett
2010-10-12 6:43 ` Josh Triplett
2010-10-11 11:59 ` Takashi Iwai
2010-10-11 11:59 ` Takashi Iwai
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