[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 84.271307][ T27] audit: type=1800 audit(1577935890.710:25): pid=8921 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 84.302385][ T27] audit: type=1800 audit(1577935890.710:26): pid=8921 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 84.347103][ T27] audit: type=1800 audit(1577935890.710:27): pid=8921 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="restorecond" dev="sda1" ino=2436 res=0 [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.0.123' (ECDSA) to the list of known hosts. executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program syzkaller login: [ 103.967855][ T469] [ 103.970478][ T469] ===================================== [ 103.976626][ T469] WARNING: bad unlock balance detected! [ 103.982442][ T469] 5.5.0-rc4-syzkaller #0 Not tainted [ 103.987806][ T469] ------------------------------------- [ 103.993478][ T469] kworker/u4:8/469 is trying to release lock (&file->mut) at: [ 104.000973][ T469] [] ucma_event_handler+0x711/0xef0 [ 104.007723][ T469] but there are no more locks to release! [ 104.014563][ T469] [ 104.014563][ T469] other info that might help us debug this: [ 104.022613][ T469] 4 locks held by kworker/u4:8/469: [ 104.027798][ T469] #0: ffff88821aa98928 ((wq_completion)ib_addr){+.+.}, at: process_one_work+0x88b/0x1740 [ 104.037799][ T469] #1: ffffc90002157dc0 ((work_completion)(&(&req->work)->work)){+.+.}, at: process_one_work+0x8c1/0x1740 [ 104.049527][ T469] #2: ffff8880a878a390 (&id_priv->handler_mutex){+.+.}, at: addr_handler+0xaf/0x3d0 [ 104.059172][ T469] #3: ffff88809dc14060 (&file->mut){+.+.}, at: ucma_event_handler+0xb3/0xef0 [ 104.068566][ T469] [ 104.068566][ T469] stack backtrace: [ 104.074641][ T469] CPU: 1 PID: 469 Comm: kworker/u4:8 Not tainted 5.5.0-rc4-syzkaller #0 [ 104.083087][ T469] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 104.093241][ T469] Workqueue: ib_addr process_one_req [ 104.098616][ T469] Call Trace: [ 104.101903][ T469] dump_stack+0x197/0x210 [ 104.106232][ T469] ? ucma_event_handler+0x711/0xef0 [ 104.111840][ T469] print_unlock_imbalance_bug.cold+0x114/0x123 [ 104.118129][ T469] ? ucma_event_handler+0x711/0xef0 [ 104.123370][ T469] lock_release+0x5f2/0x960 [ 104.127874][ T469] ? _raw_spin_unlock_irqrestore+0x66/0xe0 [ 104.133775][ T469] ? lock_downgrade+0x920/0x920 [ 104.138634][ T469] ? trace_hardirqs_on+0x67/0x240 [ 104.143708][ T469] ? _raw_spin_unlock_irqrestore+0x9f/0xe0 [ 104.149705][ T469] __mutex_unlock_slowpath+0x86/0x6a0 [ 104.155109][ T469] ? wait_for_completion+0x440/0x440 [ 104.160484][ T469] ? lockdep_hardirqs_on+0x421/0x5e0 [ 104.165800][ T469] mutex_unlock+0xd/0x10 [ 104.170035][ T469] ucma_event_handler+0x711/0xef0 [ 104.175049][ T469] addr_handler+0x2e9/0x3d0 [ 104.179636][ T469] ? cma_work_handler+0x1f0/0x1f0 [ 104.184777][ T469] ? __sanitizer_cov_trace_const_cmp1+0x1a/0x20 [ 104.191016][ T469] ? addr_resolve+0x3b0/0x1ad0 [ 104.195888][ T469] ? rdma_translate_ip+0x2f0/0x2f0 [ 104.201027][ T469] ? rcu_lockdep_current_cpu_online+0xe3/0x130 [ 104.207188][ T469] process_one_req+0x106/0x680 [ 104.212117][ T469] process_one_work+0x9af/0x1740 [ 104.217090][ T469] ? pwq_dec_nr_in_flight+0x320/0x320 [ 104.222452][ T469] ? lock_acquire+0x190/0x410 [ 104.227123][ T469] worker_thread+0x98/0xe40 [ 104.231613][ T469] ? trace_hardirqs_on+0x67/0x240 [ 104.236632][ T469] kthread+0x361/0x430 [ 104.240690][ T469] ? process_one_work+0x1740/0x1740 [ 104.246001][ T469] ? kthread_mod_delayed_work+0x1f0/0x1f0 [ 104.251987][ T469] ret_from_fork+0x24/0x30