Re: 2.6.15-git7 oopses in ext3 during LTP runs

From: Andrew Morton
Date: Wed Jan 11 2006 - 16:06:48 EST


Arjan van de Ven <arjan@xxxxxxxxxxxxx> wrote:
>
> On Wed, 2006-01-11 at 12:46 -0800, Andrew Morton wrote:
> > Andi Kleen <ak@xxxxxxx> wrote:
> > >
> > >
> > > Running LTP with the default runfile on a 4 virtual CPU x86-64
> > > system gives
> > >
> > > To reproduce: run ltp 20040908 (newer one will probably work
> > > too) with runltp -p -q -l `uname -r` on a ext3 file system
> > >
> > > config is x86-64 defconfig.
> > >
> >
> > mutex_trylock() is returning the wrong value. fs/super.c:write_super()
> > clearly took the lock.
>
>
> the conversion is buggy.
>
> mutex_trylock has the same convention as spin_try_lock (which is the
> opposite of down_trylock). THe conversion forgot to add a !
>
> --- linux-2.6.15/fs/ext3/super.c~ 2006-01-11 21:54:13.000000000 +0100
> +++ linux-2.6.15/fs/ext3/super.c 2006-01-11 21:54:13.000000000 +0100
> @@ -2150,7 +2150,7 @@
>
> static void ext3_write_super (struct super_block * sb)
> {
> - if (mutex_trylock(&sb->s_lock) != 0)
> + if (!mutex_trylock(&sb->s_lock) != 0)
> BUG();
> sb->s_dirt = 0;
> }

We expect the lock to be held on entry. Hence we expect mutex_trylock()
to return zero.
-
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