linux-kernel - Re: Bug: "bad unlock balance detected" 2.6.27-rc3-next-20080820

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Message-ID: <19f34abd0808220656x42006849ta29c423beb6bb7d4@mail.gmail.com>
Date:	Fri, 22 Aug 2008 15:56:24 +0200
From:	"Vegard Nossum" <vegard.nossum@...il.com>
To:	"David Howells" <dhowells@...hat.com>
Cc:	"jay kumar" <jaykumarks@...il.com>, linux-kernel@...r.kernel.org,
	linux-next@...r.kernel.org
Subject: Re: Bug: "bad unlock balance detected" 2.6.27-rc3-next-20080820

On Fri, Aug 22, 2008 at 3:04 PM, David Howells <dhowells@...hat.com> wrote:
>> I couldn't reproduce your original failure, but I've attempted to fix
>> it by reordering the mutex unlock and bprm free and removing the
>> extraneous unlock (see attached patch; it boots for me without
>> errors).
>
> Your patch ought to throw up its own lock failure.  You've added a
> mutex_unlock() call to the execve success path, but you haven't removed one
> from install_exec_creds().  Also, this patch is not sufficient as it doesn't
> do anything for compat_do_execve().

Ah, right. Thanks for the review anyway :-)

I didn't realize the lock should be held across the function call, I
will do a bit more research next time :-)

It seems to be a bit tricky. It would probably be nice to have
somebody else look at it too and verify that it is now indeed correct?


Vegard

-- 
"The animistic metaphor of the bug that maliciously sneaked in while
the programmer was not looking is intellectually dishonest as it
disguises that the error is the programmer's own creation."
	-- E. W. Dijkstra, EWD1036
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