===================================== WARNING: bad unlock balance detected! 4.19.179-syzkaller #0 Not tainted ------------------------------------- kworker/u4:10/11229 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/u4:10/11229: #0: 000000006566f862 ((wq_completion)"ib_addr"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2123 #1: 0000000015fb207b ((work_completion)(&(&req->work)->work)){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2127 #2: 0000000067f3167b (&id_priv->handler_mutex){+.+.}, at: addr_handler+0xaf/0x5f0 drivers/infiniband/core/cma.c:2886 #3: 000000001890d66f (&file->mut){+.+.}, at: ucma_event_handler+0xb2/0xf50 drivers/infiniband/core/ucma.c:356 stack backtrace: CPU: 0 PID: 11229 Comm: kworker/u4:10 Not tainted 4.19.179-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/0x2ef 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:2152 worker_thread+0x64c/0x1130 kernel/workqueue.c:2295 kthread+0x33f/0x460 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415