linux-kernel - Re: Unmatched semaphore usage in fs/super.c

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Message-ID: <20080302075818.GV27894@ZenIV.linux.org.uk>
Date:	Sun, 2 Mar 2008 07:58:18 +0000
From:	Al Viro <viro@...IV.linux.org.uk>
To:	Peter Teoh <htmldeveloper@...il.com>
Cc:	LKML <linux-kernel@...r.kernel.org>
Subject: Re: Unmatched semaphore usage in fs/super.c

On Sun, Mar 02, 2008 at 03:10:35PM +0800, Peter Teoh wrote:
> Please pardon me if wrong.   In fs/super.c, I saw a down_read()
> without a matching (when sb->s_root is non-zero) up_read() as shown
> below:

Correct.  get_super() and user_get_super() return locked superblock.

> Neither did the get_super() caller remember and correct the semaphore
> either.   Is this a problem?

It would be, if it would be true.  Take a look at drop_super().
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