path: root/mm/slub.c
diff options
authorBen Greear <>2011-07-07 11:36:36 -0700
committerPekka Enberg <>2011-07-07 22:17:03 +0300
commitd6543e3935cec9f66b9647c24c2e44c68f8a91fd (patch)
treef3971c6502cd6a4ea2d17af6177a8dc887ec593f /mm/slub.c
parent90810645f78f894acfb04b3768e8a7d45f2b303a (diff)
slub: Enable backtrace for create/delete points
This patch attempts to grab a backtrace for the creation and deletion points of the slub object. When a fault is detected, we can then get a better idea of where the item was deleted. Example output from debugging some funky nfs/rpc behaviour: ============================================================================= BUG kmalloc-64: Object is on free-list ----------------------------------------------------------------------------- INFO: Allocated in rpcb_getport_async+0x39c/0x5a5 [sunrpc] age=381 cpu=3 pid=3750 __slab_alloc+0x348/0x3ba kmem_cache_alloc_trace+0x67/0xe7 rpcb_getport_async+0x39c/0x5a5 [sunrpc] call_bind+0x70/0x75 [sunrpc] __rpc_execute+0x78/0x24b [sunrpc] rpc_execute+0x3d/0x42 [sunrpc] rpc_run_task+0x79/0x81 [sunrpc] rpc_call_sync+0x3f/0x60 [sunrpc] rpc_ping+0x42/0x58 [sunrpc] rpc_create+0x4aa/0x527 [sunrpc] nfs_create_rpc_client+0xb1/0xf6 [nfs] nfs_init_client+0x3b/0x7d [nfs] nfs_get_client+0x453/0x5ab [nfs] nfs_create_server+0x10b/0x437 [nfs] nfs_fs_mount+0x4ca/0x708 [nfs] mount_fs+0x6b/0x152 INFO: Freed in rpcb_map_release+0x3f/0x44 [sunrpc] age=30 cpu=2 pid=29049 __slab_free+0x57/0x150 kfree+0x107/0x13a rpcb_map_release+0x3f/0x44 [sunrpc] rpc_release_calldata+0x12/0x14 [sunrpc] rpc_free_task+0x59/0x61 [sunrpc] rpc_final_put_task+0x82/0x8a [sunrpc] __rpc_execute+0x23c/0x24b [sunrpc] rpc_async_schedule+0x10/0x12 [sunrpc] process_one_work+0x230/0x41d worker_thread+0x133/0x217 kthread+0x7d/0x85 kernel_thread_helper+0x4/0x10 INFO: Slab 0xffffea00029aa470 objects=20 used=9 fp=0xffff8800be7830d8 flags=0x20000000004081 INFO: Object 0xffff8800be7830d8 @offset=4312 fp=0xffff8800be7827a8 Bytes b4 0xffff8800be7830c8: 87 a8 96 00 01 00 00 00 5a 5a 5a 5a 5a 5a 5a 5a .�......ZZZZZZZZ Object 0xffff8800be7830d8: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk Object 0xffff8800be7830e8: 6b 6b 6b 6b 01 08 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkk..kkkkkkkkkk Object 0xffff8800be7830f8: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk Object 0xffff8800be783108: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b a5 kkkkkkkkkkkkkkk� Redzone 0xffff8800be783118: bb bb bb bb bb bb bb bb ������������� Padding 0xffff8800be783258: 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZ Pid: 29049, comm: kworker/2:2 Not tainted 3.0.0-rc4+ #8 Call Trace: [<ffffffff811055c3>] print_trailer+0x131/0x13a [<ffffffff81105601>] object_err+0x35/0x3e [<ffffffff8110746f>] verify_mem_not_deleted+0x7a/0xb7 [<ffffffffa02851b5>] rpcb_getport_done+0x23/0x126 [sunrpc] [<ffffffffa027d0ba>] rpc_exit_task+0x3f/0x6d [sunrpc] [<ffffffffa027d4ab>] __rpc_execute+0x78/0x24b [sunrpc] [<ffffffffa027d6c0>] ? rpc_execute+0x42/0x42 [sunrpc] [<ffffffffa027d6d0>] rpc_async_schedule+0x10/0x12 [sunrpc] [<ffffffff810611b7>] process_one_work+0x230/0x41d [<ffffffff81061102>] ? process_one_work+0x17b/0x41d [<ffffffff81063613>] worker_thread+0x133/0x217 [<ffffffff810634e0>] ? manage_workers+0x191/0x191 [<ffffffff81066e10>] kthread+0x7d/0x85 [<ffffffff81485924>] kernel_thread_helper+0x4/0x10 [<ffffffff8147eb18>] ? retint_restore_args+0x13/0x13 [<ffffffff81066d93>] ? __init_kthread_worker+0x56/0x56 [<ffffffff81485920>] ? gs_change+0x13/0x13 Acked-by: Christoph Lameter <> Signed-off-by: Ben Greear <> Signed-off-by: Pekka Enberg <>
Diffstat (limited to 'mm/slub.c')
1 files changed, 32 insertions, 0 deletions
diff --git a/mm/slub.c b/mm/slub.c
index 7be0223531b0..c9050995bc87 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -191,8 +191,12 @@ static LIST_HEAD(slab_caches);
* Tracking user of a slab.
struct track {
unsigned long addr; /* Called from address */
+ unsigned long addrs[TRACK_ADDRS_COUNT]; /* Called from address */
int cpu; /* Was running on cpu */
int pid; /* Pid context */
unsigned long when; /* When did the operation occur */
@@ -420,6 +424,24 @@ static void set_track(struct kmem_cache *s, void *object,
struct track *p = get_track(s, object, alloc);
if (addr) {
+ struct stack_trace trace;
+ int i;
+ trace.nr_entries = 0;
+ trace.max_entries = TRACK_ADDRS_COUNT;
+ trace.entries = p->addrs;
+ trace.skip = 3;
+ save_stack_trace(&trace);
+ /* See rant in lockdep.c */
+ if (trace.nr_entries != 0 &&
+ trace.entries[trace.nr_entries - 1] == ULONG_MAX)
+ trace.nr_entries--;
+ for (i = trace.nr_entries; i < TRACK_ADDRS_COUNT; i++)
+ p->addrs[i] = 0;
p->addr = addr;
p->cpu = smp_processor_id();
p->pid = current->pid;
@@ -444,6 +466,16 @@ static void print_track(const char *s, struct track *t)
printk(KERN_ERR "INFO: %s in %pS age=%lu cpu=%u pid=%d\n",
s, (void *)t->addr, jiffies - t->when, t->cpu, t->pid);
+ {
+ int i;
+ for (i = 0; i < TRACK_ADDRS_COUNT; i++)
+ if (t->addrs[i])
+ printk(KERN_ERR "\t%pS\n", (void *)t->addrs[i]);
+ else
+ break;
+ }
static void print_tracking(struct kmem_cache *s, void *object)