The patch titled debugobjects: fix lockdep warning has been added to the -mm tree. Its filename is debugobjects-fix-lockdep-warning.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: debugobjects: fix lockdep warning From: Vegard Nossum <vegard.nossum@xxxxxxxxx> Daniel J Blueman reported: | ======================================================= | [ INFO: possible circular locking dependency detected ] | 2.6.26-rc5-201c #1 | ------------------------------------------------------- | nscd/3669 is trying to acquire lock: | (&n->list_lock){.+..}, at: [<ffffffff802bab03>] deactivate_slab+0x173/0x1e0 | | but task is already holding lock: | (&obj_hash[i].lock){++..}, at: [<ffffffff803fa56f>] | __debug_object_init+0x2f/0x350 | | which lock already depends on the new lock. There are two locks involved here; the first is a SLUB-local lock, and the second is a debugobjects-local lock. They are basically taken in two 1. SLUB { debugobjects { ... } } 2. debugobjects { SLUB { ... } } This patch changes pattern #2 by trying to fill the memory pool (e.g. the call into SLUB/kmalloc()) outside the debugobjects lock, so now the two patterns look like this: 1. SLUB { debugobjects { ... } } 2. SLUB { } debugobjects { ... } Reviewed-by: Daniel J Blueman <daniel.blueman@xxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Signed-off-by: Vegard Nossum <vegard.nossum@xxxxxxxxx> Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- lib/debugobjects.c | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-) diff -puN lib/debugobjects.c~debugobjects-fix-lockdep-warning lib/debugobjects.c --- a/lib/debugobjects.c~debugobjects-fix-lockdep-warning +++ a/lib/debugobjects.c @@ -110,16 +110,13 @@ static struct debug_obj *lookup_object(v } /* - * Allocate a new object. If the pool is empty and no refill possible, - * switch off the debugger. + * Allocate a new object. If the pool is empty, switch off the debugger. */ static struct debug_obj * alloc_object(void *addr, struct debug_bucket *b, struct debug_obj_descr *descr) { struct debug_obj *obj = NULL; - int retry = 0; -repeat: spin_lock(&pool_lock); if (obj_pool.first) { obj = hlist_entry(obj_pool.first, typeof(*obj), node); @@ -141,9 +138,6 @@ repeat: } spin_unlock(&pool_lock); - if (fill_pool() && !obj && !retry++) - goto repeat; - return obj; } @@ -261,6 +255,8 @@ __debug_object_init(void *addr, struct d struct debug_obj *obj; unsigned long flags; + fill_pool(); + db = get_bucket((unsigned long) addr); spin_lock_irqsave(&db->lock, flags); _ Patches currently in -mm which might be from vegard.nossum@xxxxxxxxx are debugobjects-fix-lockdep-warning.patch arm-fix-header-guards.patch parisc-fix-incomplete-header-guard.patch mm-remove-initialization-of-static-per-cpu-variables.patch kallsyms-fix-potential-overflow-in-binary-search.patch kallsyms-unify-32-and-64-bit-code.patch quota-cleanup-loop-in-sync_dquots.patch quota-move-function-macros-from-quotah-to-quotaopsh-fix.patch workqueues-make-get_online_cpus-useable-for-work-func.patch s390-topology-dont-use-kthread-for-arch_reinit_sched_domains.patch taskstats-remove-initialization-of-static-per-cpu-variable.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html