===================================== WARNING: bad unlock balance detected! 4.19.160-syzkaller #0 Not tainted ------------------------------------- kworker/u4:6/8084 is trying to release lock (&file->mut) at: [] ucma_event_handler+0x745/0xf50 drivers/infiniband/core/ucma.c:396 but there are no more locks to release! other info that might help us debug this: 4 locks held by kworker/u4:6/8084: #0: 00000000eb2d6c97 ((wq_completion)"ib_addr"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2126 #1: 00000000b9903182 ((work_completion)(&(&req->work)->work)){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2130 #2: 000000001c79fb74 (&id_priv->handler_mutex){+.+.}, at: addr_handler+0xaf/0x5f0 drivers/infiniband/core/cma.c:2886 #3: 000000003ec1c41b (&file->mut){+.+.}, at: ucma_event_handler+0xb2/0xf50 drivers/infiniband/core/ucma.c:356 stack backtrace: CPU: 1 PID: 8084 Comm: kworker/u4:6 Not tainted 4.19.160-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: ib_addr process_one_req Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1fc/0x2fe lib/dump_stack.c:118 print_unlock_imbalance_bug kernel/locking/lockdep.c:149 [inline] __lock_release kernel/locking/lockdep.c:3678 [inline] lock_release.cold+0xe/0x4a kernel/locking/lockdep.c:3926 __mutex_unlock_slowpath+0x89/0x610 kernel/locking/mutex.c:1197 ucma_event_handler+0x745/0xf50 drivers/infiniband/core/ucma.c:396 addr_handler+0x2c1/0x5f0 drivers/infiniband/core/cma.c:2919 process_one_req+0xf1/0x620 drivers/infiniband/core/addr.c:569 process_one_work+0x864/0x1570 kernel/workqueue.c:2155 worker_thread+0x64c/0x1130 kernel/workqueue.c:2298 kthread+0x33f/0x460 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 [U] 3M/θ!2*V\w?oD@#n0s$H*Z^?82S@SX_W67pMT:A ~xT Iqjf>3WbD%`3WbD%`3WbD%`3WbD%`