linux-kernel - Re: [block IO crash] Re: 2.6.39-rc5-git2 boot crashs

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Date:	Wed, 4 May 2011 09:19:37 -0500 (CDT)
From:	Christoph Lameter <cl@...ux.com>
To:	Thomas Gleixner <tglx@...utronix.de>
cc:	Tejun Heo <tj@...nel.org>, Pekka Enberg <penberg@...nel.org>,
	Ingo Molnar <mingo@...e.hu>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Jens Axboe <axboe@...nel.dk>,
	Andrew Morton <akpm@...ux-foundation.org>,
	werner <w.landgraf@...ru>, "H. Peter Anvin" <hpa@...or.com>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [block IO crash] Re: 2.6.39-rc5-git2 boot crashs

On Wed, 4 May 2011, Thomas Gleixner wrote:

> Index: linux-2.6/include/linux/percpu.h
> ===================================================================
> --- linux-2.6.orig/include/linux/percpu.h
> +++ linux-2.6/include/linux/percpu.h
> @@ -948,7 +948,7 @@ do {									\
>  	irqsafe_generic_cpu_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2)
>  # endif
>  # define irqsafe_cpu_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2)	\
> -	__pcpu_double_call_return_int(irqsafe_cpu_cmpxchg_double_, (pcp1), (pcp2), (oval1), (oval2), (nval1), (nval2))
> +	__pcpu_double_call_return_bool(irqsafe_cpu_cmpxchg_double_, (pcp1), (pcp2), (oval1), (oval2), (nval1), (nval2))
>  #endif
>
>  #endif /* __LINUX_PERCPU_H */

Looking at the same thing here testing a similar patch. This should go
separately as a bug fix.

> Index: linux-2.6/mm/slub.c
> ===================================================================
> --- linux-2.6.orig/mm/slub.c
> +++ linux-2.6/mm/slub.c
> @@ -1940,7 +1940,7 @@ redo:
>  		 * Since this is without lock semantics the protection is only against
>  		 * code executing on this cpu *not* from access by other cpus.
>  		 */
> -		if (unlikely(!this_cpu_cmpxchg_double(
> +		if (unlikely(!irqsafe_cpu_cmpxchg_double(
>  				s->cpu_slab->freelist, s->cpu_slab->tid,
>  				object, tid,
>  				get_freepointer(s, object), next_tid(tid)))) {
> @@ -2145,7 +2145,7 @@ redo:
>  		set_freepointer(s, object, c->freelist);
>
>  #ifdef CONFIG_CMPXCHG_LOCAL
> -		if (unlikely(!this_cpu_cmpxchg_double(
> +		if (unlikely(!irqsafe_cpu_cmpxchg_double(
>  				s->cpu_slab->freelist, s->cpu_slab->tid,
>  				c->freelist, tid,
>  				object, next_tid(tid)))) {
>

Ok as a basic fix since it does not change the code generated for the
common x86 and other.

My version also takes out the CONFIG_CMPXCHG_LOCAL.

We could make the above two patches and then make the CONFIG_CMPXCHG_LOCAL
removal a separate one (since it requires some benchmarking).

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