On Sat, 8 Feb 2014, Gautham R Shenoy wrote: > Hi, > > From the lockdep annotation and the comment that existed before the > lockdep annotations were introduced, > mm/slub.c:add_full(s, n, page) expects to be called with n->list_lock > held. > > However, there's a call path in deactivate_slab() when > > (new.inuse || n->nr_partial <= s->min_partial) && > !(new.freelist) && > !(kmem_cache_debug(s)) > > which ends up calling add_full() without holding > n->list_lock. > > This was discovered while onlining/offlining cpus in 3.14-rc1 due to > the lockdep annotations added by commit > c65c1877bd6826ce0d9713d76e30a7bed8e49f38. > > Fix this by unconditionally taking the lock > irrespective of the state of kmem_cache_debug(s). > > Cc: Peter Zijlstra <pet...@infradead.org> > Cc: Pekka Enberg <penb...@kernel.org> > Signed-off-by: Gautham R. Shenoy <e...@linux.vnet.ibm.com>
No, it's not needed unless kmem_cache_debug(s) is actually set, specifically s->flags & SLAB_STORE_USER. You want the patch at http://marc.info/?l=linux-kernel&m=139147105027693 instead which is already in -mm and linux-next. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
