[4/4] SLAB: Fix node add timer race in cache_reap
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From: Christoph Lameter on 5 Feb 2010 14:20 Acked-by: Christoph Lameter <cl(a)linux-foundation.org> -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: David Rientjes on 11 Feb 2010 16:50 On Thu, 11 Feb 2010, Andi Kleen wrote: > > cache_reap can run before the node is set up and then reference a NULL > l3 list. Check for this explicitely and just continue. The node > will be eventually set up. > > Signed-off-by: Andi Kleen <ak(a)linux.intel.com> Acked-by: David Rientjes <rientjes(a)google.com> -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Nick Piggin on 15 Feb 2010 01:20 On Thu, Feb 11, 2010 at 09:54:04PM +0100, Andi Kleen wrote: > > cache_reap can run before the node is set up and then reference a NULL > l3 list. Check for this explicitely and just continue. The node > will be eventually set up. How, may I ask? cpuup_prepare in the hotplug notifier should always run before start_cpu_timer. > > Signed-off-by: Andi Kleen <ak(a)linux.intel.com> > > --- > mm/slab.c | 3 +++ > 1 file changed, 3 insertions(+) > > Index: linux-2.6.32-memhotadd/mm/slab.c > =================================================================== > --- linux-2.6.32-memhotadd.orig/mm/slab.c > +++ linux-2.6.32-memhotadd/mm/slab.c > @@ -4093,6 +4093,9 @@ static void cache_reap(struct work_struc > * we can do some work if the lock was obtained. > */ > l3 = searchp->nodelists[node]; > + /* Note node yet set up */ > + if (!l3) > + break; > > reap_alien(searchp, l3); > > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo(a)kvack.org. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: <a href=mailto:"dont(a)kvack.org"> email(a)kvack.org </a> -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Andi Kleen on 15 Feb 2010 05:40 On Mon, Feb 15, 2010 at 05:15:35PM +1100, Nick Piggin wrote: > On Thu, Feb 11, 2010 at 09:54:04PM +0100, Andi Kleen wrote: > > > > cache_reap can run before the node is set up and then reference a NULL > > l3 list. Check for this explicitely and just continue. The node > > will be eventually set up. > > How, may I ask? cpuup_prepare in the hotplug notifier should always > run before start_cpu_timer. I'm not fully sure, but I have the oops to prove it :) -Andi -- ak(a)linux.intel.com -- Speaking for myself only. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Nick Piggin on 15 Feb 2010 05:50
On Mon, Feb 15, 2010 at 11:32:50AM +0100, Andi Kleen wrote: > On Mon, Feb 15, 2010 at 05:15:35PM +1100, Nick Piggin wrote: > > On Thu, Feb 11, 2010 at 09:54:04PM +0100, Andi Kleen wrote: > > > > > > cache_reap can run before the node is set up and then reference a NULL > > > l3 list. Check for this explicitely and just continue. The node > > > will be eventually set up. > > > > How, may I ask? cpuup_prepare in the hotplug notifier should always > > run before start_cpu_timer. > > I'm not fully sure, but I have the oops to prove it :) Hmm, it would be nice to work out why it's happening. If it's completely reproducible then could I send you a debug patch to test? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |