program: r0 = socket$inet6_tcp(0xa, 0x1, 0x0) close(r0) r1 = socket(0x2b, 0x1, 0x1) bind$inet6(r0, &(0x7f0000000080)={0xa, 0x4e22, 0x0, @empty}, 0x1c) listen(r1, 0x5) r2 = socket$inet_smc(0x2b, 0x1, 0x0) connect$inet(r2, &(0x7f0000000000)={0x2, 0x4e22, @local}, 0x10) setsockopt$inet_int(r2, 0x0, 0x19, &(0x7f00000000c0)=0x2, 0x4) [ 109.612243][ T5290] Bluetooth: hci0: command tx timeout [ 109.771229][ T5331] [ 109.772372][ T5331] ====================================================== [ 109.775419][ T5331] WARNING: possible circular locking dependency detected [ 109.778582][ T5331] syzkaller #0 Not tainted [ 109.780545][ T5331] ------------------------------------------------------ [ 109.783711][ T5331] syz.0.0/5331 is trying to acquire lock: [ 109.786510][ T5331] ffff888036748a68 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: __flush_work+0x101/0xca0 [ 109.791980][ T5331] [ 109.791980][ T5331] but task is already holding lock: [ 109.795119][ T5331] ffff888036748ee0 (sk_lock-AF_SMC/1){+.+.}-{0:0}, at: smc_release+0x24d/0x550 [ 109.799425][ T5331] [ 109.799425][ T5331] which lock already depends on the new lock. [ 109.799425][ T5331] [ 109.804341][ T5331] [ 109.804341][ T5331] the existing dependency chain (in reverse order) is: [ 109.809303][ T5331] [ 109.809303][ T5331] -> #1 (sk_lock-AF_SMC/1){+.+.}-{0:0}: [ 109.814425][ T5331] lock_sock_nested+0x41/0x100 [ 109.817489][ T5331] smc_listen_out+0x105/0x3c0 [ 109.820157][ T5331] smc_listen_work+0x81d/0x1410 [ 109.822944][ T5331] process_scheduled_works+0xa8e/0x14e0 [ 109.826461][ T5331] worker_thread+0xa47/0xfb0 [ 109.829561][ T5331] kthread+0x388/0x470 [ 109.831935][ T5331] ret_from_fork+0x514/0xb70 [ 109.834358][ T5331] ret_from_fork_asm+0x1a/0x30 [ 109.836738][ T5331] [ 109.836738][ T5331] -> #0 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}: [ 109.840907][ T5331] __lock_acquire+0x1520/0x2cf0 [ 109.843185][ T5331] lock_acquire+0x106/0x350 [ 109.846316][ T5331] __flush_work+0x74c/0xca0 [ 109.849709][ T5331] __cancel_work_sync+0xbe/0x110 [ 109.852685][ T5331] smc_clcsock_release+0x60/0xf0 [ 109.855501][ T5331] __smc_release+0x64e/0x7c0 [ 109.858128][ T5331] smc_close_non_accepted+0xd5/0x1f0 [ 109.861001][ T5331] smc_close_active+0xb42/0xf30 [ 109.864211][ T5331] __smc_release+0x9c/0x7c0 [ 109.866988][ T5331] smc_release+0x2c5/0x550 [ 109.869531][ T5331] sock_close+0xad/0x220 [ 109.871660][ T5331] __fput+0x418/0xa50 [ 109.873541][ T5331] task_work_run+0x1d9/0x270 [ 109.875427][ T5331] exit_to_user_mode_loop+0x1fa/0x730 [ 109.878080][ T5331] do_syscall_64+0x353/0x580 [ 109.880759][ T5331] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 109.883807][ T5331] [ 109.883807][ T5331] other info that might help us debug this: [ 109.883807][ T5331] [ 109.888052][ T5331] Possible unsafe locking scenario: [ 109.888052][ T5331] [ 109.891041][ T5331] CPU0 CPU1 [ 109.893464][ T5331] ---- ---- [ 109.896499][ T5331] lock(sk_lock-AF_SMC/1); [ 109.898738][ T5331] lock((work_completion)(&new_smc->smc_listen_work)); [ 109.902578][ T5331] lock(sk_lock-AF_SMC/1); [ 109.905473][ T5331] lock((work_completion)(&new_smc->smc_listen_work)); [ 109.909063][ T5331] [ 109.909063][ T5331] *** DEADLOCK *** [ 109.909063][ T5331] [ 109.913047][ T5331] 3 locks held by syz.0.0/5331: [ 109.915111][ T5331] #0: ffff888043d2fbc0 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: sock_close+0x82/0x220 [ 109.919520][ T5331] #1: ffff888036748ee0 (sk_lock-AF_SMC/1){+.+.}-{0:0}, at: smc_release+0x24d/0x550 [ 109.923914][ T5331] #2: ffffffff8e959c20 (rcu_read_lock){....}-{1:3}, at: __flush_work+0x101/0xca0 [ 109.928230][ T5331] [ 109.928230][ T5331] stack backtrace: [ 109.930755][ T5331] CPU: 0 UID: 0 PID: 5331 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full) [ 109.930776][ T5331] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 109.930782][ T5331] Call Trace: [ 109.930789][ T5331] [ 109.930795][ T5331] dump_stack_lvl+0xe8/0x150 [ 109.930813][ T5331] print_circular_bug+0x2e1/0x300 [ 109.930832][ T5331] check_noncircular+0x12e/0x150 [ 109.930846][ T5331] __lock_acquire+0x1520/0x2cf0 [ 109.930859][ T5331] ? __pfx___schedule+0x10/0x10 [ 109.930876][ T5331] ? irqentry_exit+0x218/0x8f0 [ 109.930885][ T5331] ? irqentry_exit+0x218/0x8f0 [ 109.930894][ T5331] ? trace_irq_disable+0x3b/0x140 [ 109.930903][ T5331] ? __flush_work+0x101/0xca0 [ 109.930911][ T5331] lock_acquire+0x106/0x350 [ 109.930921][ T5331] ? __flush_work+0x101/0xca0 [ 109.930930][ T5331] ? preempt_schedule_thunk+0x16/0x40 [ 109.930946][ T5331] ? __flush_work+0x101/0xca0 [ 109.930955][ T5331] __flush_work+0x74c/0xca0 [ 109.930963][ T5331] ? __flush_work+0x101/0xca0 [ 109.930971][ T5331] ? __flush_work+0x101/0xca0 [ 109.930980][ T5331] ? __pfx___flush_work+0x10/0x10 [ 109.930989][ T5331] ? __pfx_wq_barrier_func+0x10/0x10 [ 109.931006][ T5331] ? __cancel_work_sync+0x5c/0x110 [ 109.931045][ T5331] __cancel_work_sync+0xbe/0x110 [ 109.931054][ T5331] smc_clcsock_release+0x60/0xf0 [ 109.931067][ T5331] __smc_release+0x64e/0x7c0 [ 109.931084][ T5331] smc_close_non_accepted+0xd5/0x1f0 [ 109.931095][ T5331] smc_close_active+0xb42/0xf30 [ 109.931106][ T5331] ? __pfx_sock_def_readable+0x10/0x10 [ 109.931121][ T5331] __smc_release+0x9c/0x7c0 [ 109.931134][ T5331] ? __local_bh_enable_ip+0xd0/0x130 [ 109.931152][ T5331] smc_release+0x2c5/0x550 [ 109.931167][ T5331] sock_close+0xad/0x220 [ 109.931180][ T5331] ? __pfx_sock_close+0x10/0x10 [ 109.931192][ T5331] __fput+0x418/0xa50 [ 109.931207][ T5331] task_work_run+0x1d9/0x270 [ 109.931218][ T5331] ? __pfx_task_work_run+0x10/0x10 [ 109.931230][ T5331] exit_to_user_mode_loop+0x1fa/0x730 [ 109.931241][ T5331] ? rcu_is_watching+0x15/0xb0 [ 109.931254][ T5331] ? entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 109.931265][ T5331] do_syscall_64+0x353/0x580 [ 109.931276][ T5331] ? clear_bhb_loop+0x40/0x90 [ 109.931288][ T5331] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 109.931298][ T5331] RIP: 0033:0x7fdaae59ce59 [ 109.931309][ T5331] Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 [ 109.931318][ T5331] RSP: 002b:00007ffd12f6e458 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 [ 109.931330][ T5331] RAX: 0000000000000000 RBX: 00007ffd12f6e540 RCX: 00007fdaae59ce59 [ 109.931337][ T5331] RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 [ 109.931342][ T5331] RBP: 000000000001abde R08: 0000000000000001 R09: 0000000000000000 [ 109.931348][ T5331] R10: 00007fdaae3ff02c R11: 0000000000000246 R12: 00007ffd12f6e580 [ 109.931355][ T5331] R13: 00007fdaae815fac R14: 000000000001ac49 R15: 00007fdaae815fa0 [ 109.931372][ T5331]