sysfs_slab_add() shouldn't call kobject_put at error path: this puts last reference of kmem-cache kobject and frees it. Kmem cache will be freed second time at error path in kmem_cache_create(). For example this happens when slub debug was enabled in runtime and somebody creates new kmem cache: # echo 1 | tee /sys/kernel/slab/*/sanity_checks # modprobe configfs "configfs_dir_cache" cannot be merged because existing slab have debug and cannot create new slab because unique name ":t-0000096" already taken. Signed-off-by: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx> --- [ 56.648477] ------------[ cut here ]------------ [ 56.648503] WARNING: CPU: 2 PID: 3087 at fs/sysfs/dir.c:31 sysfs_warn_dup+0x6a/0x80() [ 56.648504] sysfs: cannot create duplicate filename '/kernel/slab/:t-0000096' [ 56.648505] Modules linked in: configfs(+) [ 56.648514] CPU: 2 PID: 3087 Comm: modprobe Not tainted 4.2.0-rc2+ #109 [ 56.648516] Hardware name: OpenStack Foundation OpenStack Nova, BIOS Bochs 01/01/2011 [ 56.648517] 000000000000001f ffff88023184f998 ffffffff819d5bb0 0000000000000007 [ 56.648520] ffff88023184f9e8 ffff88023184f9d8 ffffffff8105d0e2 ffff8802348ca000 [ 56.648523] ffff8802348ca000 ffff8802348b0420 ffff880234c98558 0000000000000000 [ 56.648526] Call Trace: [ 56.648555] [<ffffffff819d5bb0>] dump_stack+0x4c/0x65 [ 56.648565] [<ffffffff8105d0e2>] warn_slowpath_common+0x92/0xd0 [ 56.648567] [<ffffffff8105d1c1>] warn_slowpath_fmt+0x41/0x50 [ 56.648572] [<ffffffff8123f5d0>] ? kernfs_path+0x50/0x70 [ 56.648574] [<ffffffff81242a5a>] sysfs_warn_dup+0x6a/0x80 [ 56.648576] [<ffffffff81242b37>] sysfs_create_dir_ns+0x77/0x80 [ 56.648589] [<ffffffff813aa021>] kobject_add_internal+0xa1/0x2d0 [ 56.648591] [<ffffffff813aa3a3>] kobject_init_and_add+0x63/0x90 [ 56.648613] [<ffffffff811a7a46>] sysfs_slab_add+0x76/0x1a0 [ 56.648617] [<ffffffff811a8fdb>] __kmem_cache_create+0x3eb/0x5a0 [ 56.648620] [<ffffffff811a71ab>] ? kmem_cache_alloc+0x1db/0x2e0 [ 56.648624] [<ffffffff811761c0>] kmem_cache_create+0x1e0/0x380 [ 56.648626] [<ffffffff811a778c>] ? kfree+0xec/0x330 [ 56.648629] [<ffffffffa0008023>] configfs_init+0x23/0x98 [configfs] [ 56.648631] [<ffffffffa0008000>] ? 0xffffffffa0008000 [ 56.648638] [<ffffffff810002d1>] do_one_initcall+0x81/0x1b0 [ 56.648641] [<ffffffff811a6b26>] ? kmem_cache_alloc_trace+0x1d6/0x2e0 [ 56.648648] [<ffffffff810edaff>] do_init_module+0x5f/0x210 [ 56.648650] [<ffffffff810ef8af>] load_module+0x116f/0x17a0 [ 56.648653] [<ffffffff810eb930>] ? show_initstate+0x50/0x50 [ 56.648655] [<ffffffff810f0005>] SyS_init_module+0x125/0x150 [ 56.648661] [<ffffffff819e29ae>] entry_SYSCALL_64_fastpath+0x12/0x76 [ 56.648662] ---[ end trace ceccd457b71b3f60 ]--- [ 56.648667] ------------[ cut here ]------------ [ 56.648670] WARNING: CPU: 2 PID: 3087 at lib/kobject.c:240 kobject_add_internal+0x25c/0x2d0() [ 56.648671] kobject_add_internal failed for :t-0000096 with -EEXIST, don't try to register things with the same name in the same directory. [ 56.648672] Modules linked in: configfs(+) [ 56.648674] CPU: 2 PID: 3087 Comm: modprobe Tainted: G W 4.2.0-rc2+ #109 [ 56.648675] Hardware name: OpenStack Foundation OpenStack Nova, BIOS Bochs 01/01/2011 [ 56.648676] 00000000000000f0 ffff88023184f9f8 ffffffff819d5bb0 0000000000000007 [ 56.648679] ffff88023184fa48 ffff88023184fa38 ffffffff8105d0e2 0000000235c40aa8 [ 56.648681] 00000000ffffffef ffff880234d8da78 0000000000000000 0000000000000000 [ 56.648684] Call Trace: [ 56.648688] [<ffffffff819d5bb0>] dump_stack+0x4c/0x65 [ 56.648690] [<ffffffff8105d0e2>] warn_slowpath_common+0x92/0xd0 [ 56.648692] [<ffffffff8105d1c1>] warn_slowpath_fmt+0x41/0x50 [ 56.648694] [<ffffffff813aa1dc>] kobject_add_internal+0x25c/0x2d0 [ 56.648696] [<ffffffff813aa3a3>] kobject_init_and_add+0x63/0x90 [ 56.648698] [<ffffffff811a7a46>] sysfs_slab_add+0x76/0x1a0 [ 56.648700] [<ffffffff811a8fdb>] __kmem_cache_create+0x3eb/0x5a0 [ 56.648702] [<ffffffff811a71ab>] ? kmem_cache_alloc+0x1db/0x2e0 [ 56.648704] [<ffffffff811761c0>] kmem_cache_create+0x1e0/0x380 [ 56.648706] [<ffffffff811a778c>] ? kfree+0xec/0x330 [ 56.648709] [<ffffffffa0008023>] configfs_init+0x23/0x98 [configfs] [ 56.648710] [<ffffffffa0008000>] ? 0xffffffffa0008000 [ 56.648712] [<ffffffff810002d1>] do_one_initcall+0x81/0x1b0 [ 56.648715] [<ffffffff811a6b26>] ? kmem_cache_alloc_trace+0x1d6/0x2e0 [ 56.648716] [<ffffffff810edaff>] do_init_module+0x5f/0x210 [ 56.648718] [<ffffffff810ef8af>] load_module+0x116f/0x17a0 [ 56.648720] [<ffffffff810eb930>] ? show_initstate+0x50/0x50 [ 56.648723] [<ffffffff810f0005>] SyS_init_module+0x125/0x150 [ 56.648725] [<ffffffff819e29ae>] entry_SYSCALL_64_fastpath+0x12/0x76 [ 56.648726] ---[ end trace ceccd457b71b3f61 ]--- [ 56.648745] general protection fault: 0000 [#1] SMP [ 56.649035] Modules linked in: configfs(+) [ 56.649035] CPU: 2 PID: 3087 Comm: modprobe Tainted: G W 4.2.0-rc2+ #109 [ 56.649035] Hardware name: OpenStack Foundation OpenStack Nova, BIOS Bochs 01/01/2011 [ 56.649035] task: ffff880235d70000 ti: ffff88023184c000 task.ti: ffff88023184c000 [ 56.649035] RIP: 0010:[<ffffffff811a2907>] [<ffffffff811a2907>] has_cpu_slab+0x17/0x30 [ 56.649035] RSP: 0018:ffff88023184fb48 EFLAGS: 00010287 [ 56.649035] RAX: 0000000000000001 RBX: ffff880234d8da00 RCX: 0000000000000000 [ 56.649035] RDX: ffff10047498db00 RSI: ffff880234d8da00 RDI: 0000000000000000 [ 56.649035] RBP: ffff88023184fb48 R08: 0000000000000000 R09: 0000000000000000 [ 56.649035] R10: 0000000000000001 R11: 0000000000000000 R12: ffffffff811a28f0 [ 56.649035] R13: ffffffff811a5b70 R14: 0000000000000001 R15: ffffffff81f2a048 [ 56.649035] FS: 00007f3f44b16700(0000) GS:ffff88023fd00000(0000) knlGS:0000000000000000 [ 56.649035] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 56.649035] CR2: 00007f3f44b09000 CR3: 00000000bb0e6000 CR4: 00000000000006e0 [ 56.649035] Stack: [ 56.649035] ffff88023184fba8 ffffffff810e9ae6 ffff880233faf680 ffff880200000000 [ 56.649035] 0000000000000000 0000000000000000 ffff88023184fbb8 ffff880234d8da00 [ 56.649035] ffffffff81f2a050 0000000000000040 ffff8800bad34d00 0000000000000040 [ 56.649035] Call Trace: [ 56.649035] [<ffffffff810e9ae6>] on_each_cpu_cond+0x66/0xc0 [ 56.649035] [<ffffffff811a2f95>] flush_all+0x25/0x30 [ 56.649035] [<ffffffff811a8fee>] __kmem_cache_create+0x3fe/0x5a0 [ 56.649035] [<ffffffff811a71ab>] ? kmem_cache_alloc+0x1db/0x2e0 [ 56.649035] [<ffffffff811761c0>] kmem_cache_create+0x1e0/0x380 [ 56.649035] [<ffffffff811a778c>] ? kfree+0xec/0x330 [ 56.649035] [<ffffffffa0008023>] configfs_init+0x23/0x98 [configfs] [ 56.649035] [<ffffffffa0008000>] ? 0xffffffffa0008000 [ 56.649035] [<ffffffff810002d1>] do_one_initcall+0x81/0x1b0 [ 56.649035] [<ffffffff811a6b26>] ? kmem_cache_alloc_trace+0x1d6/0x2e0 [ 56.649035] [<ffffffff810edaff>] do_init_module+0x5f/0x210 [ 56.649035] [<ffffffff810ef8af>] load_module+0x116f/0x17a0 [ 56.649035] [<ffffffff810eb930>] ? show_initstate+0x50/0x50 [ 56.649035] [<ffffffff810f0005>] SyS_init_module+0x125/0x150 [ 56.649035] [<ffffffff819e29ae>] entry_SYSCALL_64_fastpath+0x12/0x76 [ 56.649035] Code: 89 c2 fa 66 66 90 66 66 90 48 89 d0 5d c3 66 0f 1f 44 00 00 48 63 ff 48 8b 16 55 48 03 14 fd 20 98 f2 81 48 89 e5 b8 01 00 00 00 <48> 83 7a 10 00 74 02 5d c3 48 83 7a 18 00 5d 0f 95 c0 c3 66 0f [ 56.649035] RIP [<ffffffff811a2907>] has_cpu_slab+0x17/0x30 [ 56.649035] RSP <ffff88023184fb48> [ 56.702092] ---[ end trace ceccd457b71b3f62 ]--- [ 56.703100] BUG: sleeping function called from invalid context at include/linux/sched.h:2727 [ 56.704858] in_atomic(): 1, irqs_disabled(): 0, pid: 3087, name: modprobe [ 56.706276] INFO: lockdep is turned off. [ 56.707087] CPU: 2 PID: 3087 Comm: modprobe Tainted: G D W 4.2.0-rc2+ #109 [ 56.708710] Hardware name: OpenStack Foundation OpenStack Nova, BIOS Bochs 01/01/2011 [ 56.710326] ffffffff81caeb0a ffff88023184f8e8 ffffffff819d5bb0 ffffffff810bf0fe [ 56.711911] ffff880235d70000 ffff88023184f918 ffffffff81085f48 ffffffff833ee142 [ 56.713579] 0000000000000000 0000000000000aa7 ffffffff81caeb0a ffff88023184f948 [ 56.715187] Call Trace: [ 56.715691] [<ffffffff819d5bb0>] dump_stack+0x4c/0x65 [ 56.716783] [<ffffffff810bf0fe>] ? console_unlock+0x28e/0x4e0 [ 56.717980] [<ffffffff81085f48>] ___might_sleep+0x188/0x240 [ 56.719125] [<ffffffff8108604d>] __might_sleep+0x4d/0x90 [ 56.720264] [<ffffffff8106e1cf>] exit_signals+0x1f/0x130 [ 56.721390] [<ffffffff81081381>] ? blocking_notifier_call_chain+0x11/0x20 [ 56.722759] [<ffffffff8106012c>] do_exit+0xac/0xc10 [ 56.723775] [<ffffffff810c01b1>] ? kmsg_dump+0x111/0x190 [ 56.724866] [<ffffffff810c00bf>] ? kmsg_dump+0x1f/0x190 [ 56.725942] [<ffffffff81007282>] oops_end+0xa2/0xe0 [ 56.726969] [<ffffffff81007763>] die+0x53/0x80 [ 56.727906] [<ffffffff81003f1b>] do_general_protection+0xdb/0x160 [ 56.729156] [<ffffffff819e35f7>] ? native_iret+0x7/0x7 [ 56.730178] [<ffffffff811a28f0>] ? arch_local_irq_save+0x20/0x20 [ 56.731415] [<ffffffff811a5b70>] ? slab_cpuup_callback+0x110/0x110 [ 56.732649] [<ffffffff819e4828>] general_protection+0x28/0x30 [ 56.733829] [<ffffffff811a5b70>] ? slab_cpuup_callback+0x110/0x110 [ 56.735057] [<ffffffff811a28f0>] ? arch_local_irq_save+0x20/0x20 [ 56.736297] [<ffffffff811a2907>] ? has_cpu_slab+0x17/0x30 [ 56.737412] [<ffffffff810e9ae6>] on_each_cpu_cond+0x66/0xc0 [ 56.738566] [<ffffffff811a2f95>] flush_all+0x25/0x30 [ 56.739572] [<ffffffff811a8fee>] __kmem_cache_create+0x3fe/0x5a0 [ 56.740849] [<ffffffff811a71ab>] ? kmem_cache_alloc+0x1db/0x2e0 [ 56.742026] [<ffffffff811761c0>] kmem_cache_create+0x1e0/0x380 [ 56.743222] [<ffffffff811a778c>] ? kfree+0xec/0x330 [ 56.744211] [<ffffffffa0008023>] configfs_init+0x23/0x98 [configfs] [ 56.745497] [<ffffffffa0008000>] ? 0xffffffffa0008000 [ 56.746555] [<ffffffff810002d1>] do_one_initcall+0x81/0x1b0 [ 56.747728] [<ffffffff811a6b26>] ? kmem_cache_alloc_trace+0x1d6/0x2e0 [ 56.749310] [<ffffffff810edaff>] do_init_module+0x5f/0x210 [ 56.750467] [<ffffffff810ef8af>] load_module+0x116f/0x17a0 [ 56.751561] [<ffffffff810eb930>] ? show_initstate+0x50/0x50 [ 56.752762] [<ffffffff810f0005>] SyS_init_module+0x125/0x150 [ 56.753902] [<ffffffff819e29ae>] entry_SYSCALL_64_fastpath+0x12/0x76 [ 56.755220] note: modprobe[3087] exited with preempt_count 1 --- mm/slub.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/mm/slub.c b/mm/slub.c index 816df0016555..4497cae6a914 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -5181,7 +5181,7 @@ static int sysfs_slab_add(struct kmem_cache *s) s->kobj.kset = cache_kset(s); err = kobject_init_and_add(&s->kobj, &slab_ktype, NULL, "%s", name); if (err) - goto out_put_kobj; + goto out; err = sysfs_create_group(&s->kobj, &slab_attr_group); if (err) @@ -5208,8 +5208,6 @@ out: return err; out_del_kobj: kobject_del(&s->kobj); -out_put_kobj: - kobject_put(&s->kobj); goto out; } -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. 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