Messages in this thread Patch in this message | | | From | Nick Piggin <> | Subject | Re: SLOB lockup (was: Re: [tip:core/locking] lockdep: annotate reclaim context (__GFP_NOFS), fix SLOB) | Date | Sun, 15 Mar 2009 20:06:20 +1100 |
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On Sunday 15 March 2009 17:48:18 Ingo Molnar wrote:
> > Cc: Nick Piggin <npiggin@suse.de> > > Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> > > LKML-Reference: <20090128135457.350751756@chello.nl> > > Signed-off-by: Ingo Molnar <mingo@elte.hu> > > and with this fixed, and with SLOB now being tested in -tip, the > new lockdep assert attached below (followed by a real lockup) > pops up. > > Seems like a genuine SLOB bug, probably present upstream as > well.
Hmmf. debugobjects calls back into the slab allocator from the page allocator. The following patch would improve SLOB, but I think it would be a good idea to avoid a dependency in that direction. Can debugobjects defer this freeing?
--- mm/slob.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
Index: linux-2.6/mm/slob.c =================================================================== --- linux-2.6.orig/mm/slob.c +++ linux-2.6/mm/slob.c @@ -390,13 +390,14 @@ static void slob_free(void *block, int s spin_lock_irqsave(&slob_lock, flags); if (sp->units + units == SLOB_UNITS(PAGE_SIZE)) { + spin_lock_irqrestore(&slob_lock, flags); /* Go directly to page allocator. Do not pass slob allocator */ if (slob_page_free(sp)) clear_slob_page_free(sp); clear_slob_page(sp); free_slob_page(sp); free_page((unsigned long)b); - goto out; + return; } if (!slob_page_free(sp)) {
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