wq->lockdep_map is set only after __alloc_workqueue()
successfully returns. However, on its error path
__alloc_workqueue() may call destroy_workqueue() which
expects wq->lockdep_map to be already set, which results
in a null-ptr-deref in touch_wq_lockdep_map().
Add a simple NULL-check to touch_wq_lockdep_map().
Oops: general protection fault, probably for non-canonical address
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
RIP: 0010:__lock_acquire+0x81/0x7800
[..]
Call Trace:
<TASK>
? __die_body+0x66/0xb0
? die_addr+0xb2/0xe0
? exc_general_protection+0x300/0x470
? asm_exc_general_protection+0x22/0x30
? __lock_acquire+0x81/0x7800
? mark_lock+0x94/0x330
? __lock_acquire+0x12fd/0x7800
? __lock_acquire+0x3439/0x7800
lock_acquire+0x14c/0x3e0
? __flush_workqueue+0x167/0x13a0
? __init_swait_queue_head+0xaf/0x150
? __flush_workqueue+0x167/0x13a0
__flush_workqueue+0x17d/0x13a0
? __flush_workqueue+0x167/0x13a0
? lock_release+0x50f/0x830
? drain_workqueue+0x94/0x300
drain_workqueue+0xe3/0x300
destroy_workqueue+0xac/0xc40
? workqueue_sysfs_register+0x159/0x2f0
__alloc_workqueue+0x1506/0x1760
alloc_workqueue+0x61/0x150
...
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
84c425bef3