program: socket$packet(0x11, 0x2, 0x300) r0 = socket$kcm(0x2, 0x3, 0x106) sendmsg$inet(r0, &(0x7f0000000340)={&(0x7f0000000380)={0x2, 0x0, @remote}, 0x10, &(0x7f0000000300)=[{&(0x7f0000000080)="b5fa4fc5060000ffffff970386780df56e5be7070101080a4e7719b506a0977b", 0xffbf}], 0x1}, 0x0) r1 = socket$inet6_tcp(0xa, 0x1, 0x0) close(r1) socket(0x2b, 0x1, 0x1) bind$inet6(r1, &(0x7f0000000040)={0xa, 0x4e22, 0x0, @empty}, 0x1c) listen(r1, 0x0) r2 = socket$inet_smc(0x2b, 0x1, 0x0) connect$inet(r2, &(0x7f0000000000)={0x2, 0x4e22, @local}, 0x10) [ 87.235863][ T5294] Bluetooth: hci0: command tx timeout [ 87.388977][ T5334] [ 87.390063][ T5334] ====================================================== [ 87.392930][ T5334] WARNING: possible circular locking dependency detected [ 87.395905][ T5334] syzkaller #0 Not tainted [ 87.397780][ T5334] ------------------------------------------------------ [ 87.401259][ T5334] syz.0.0/5334 is trying to acquire lock: [ 87.403886][ T5334] ffff88800e488a68 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: __flush_work+0x101/0xca0 [ 87.408486][ T5334] [ 87.408486][ T5334] but task is already holding lock: [ 87.411431][ T5334] ffff88800e488ee0 (sk_lock-AF_SMC/1){+.+.}-{0:0}, at: smc_release+0x24d/0x550 [ 87.415158][ T5334] [ 87.415158][ T5334] which lock already depends on the new lock. [ 87.415158][ T5334] [ 87.419692][ T5334] [ 87.419692][ T5334] the existing dependency chain (in reverse order) is: [ 87.423744][ T5334] [ 87.423744][ T5334] -> #1 (sk_lock-AF_SMC/1){+.+.}-{0:0}: [ 87.427121][ T5334] lock_sock_nested+0x41/0x100 [ 87.429969][ T5334] smc_listen_out+0x105/0x3c0 [ 87.431983][ T5334] smc_listen_work+0x81d/0x1410 [ 87.434079][ T5334] process_scheduled_works+0xa8e/0x14e0 [ 87.436402][ T5334] worker_thread+0xa47/0xfb0 [ 87.438602][ T5334] kthread+0x389/0x470 [ 87.440341][ T5334] ret_from_fork+0x514/0xb70 [ 87.442277][ T5334] ret_from_fork_asm+0x1a/0x30 [ 87.444278][ T5334] [ 87.444278][ T5334] -> #0 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}: [ 87.448427][ T5334] __lock_acquire+0x1520/0x2cd0 [ 87.450671][ T5334] lock_acquire+0x106/0x350 [ 87.452858][ T5334] __flush_work+0x74c/0xca0 [ 87.455028][ T5334] __cancel_work_sync+0xbe/0x110 [ 87.457355][ T5334] smc_clcsock_release+0x60/0xf0 [ 87.459559][ T5334] __smc_release+0x64e/0x7c0 [ 87.461640][ T5334] smc_close_non_accepted+0xd5/0x1f0 [ 87.464027][ T5334] smc_close_active+0xb42/0xf30 [ 87.466371][ T5334] __smc_release+0x9c/0x7c0 [ 87.468601][ T5334] smc_release+0x2c5/0x550 [ 87.470658][ T5334] sock_close+0xad/0x220 [ 87.472633][ T5334] __fput+0x418/0xa50 [ 87.474501][ T5334] task_work_run+0x1d9/0x270 [ 87.476574][ T5334] exit_to_user_mode_loop+0x193/0x6b0 [ 87.478981][ T5334] do_syscall_64+0x353/0x580 [ 87.481056][ T5334] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 87.483628][ T5334] [ 87.483628][ T5334] other info that might help us debug this: [ 87.483628][ T5334] [ 87.487865][ T5334] Possible unsafe locking scenario: [ 87.487865][ T5334] [ 87.490853][ T5334] CPU0 CPU1 [ 87.493072][ T5334] ---- ---- [ 87.495177][ T5334] lock(sk_lock-AF_SMC/1); [ 87.496944][ T5334] lock((work_completion)(&new_smc->smc_listen_work)); [ 87.500506][ T5334] lock(sk_lock-AF_SMC/1); [ 87.503217][ T5334] lock((work_completion)(&new_smc->smc_listen_work)); [ 87.505938][ T5334] [ 87.505938][ T5334] *** DEADLOCK *** [ 87.505938][ T5334] [ 87.509066][ T5334] 3 locks held by syz.0.0/5334: [ 87.511073][ T5334] #0: ffff88801f52d380 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: sock_close+0x82/0x220 [ 87.515467][ T5334] #1: ffff88800e488ee0 (sk_lock-AF_SMC/1){+.+.}-{0:0}, at: smc_release+0x24d/0x550 [ 87.519482][ T5334] #2: ffffffff8e95c780 (rcu_read_lock){....}-{1:3}, at: __flush_work+0x101/0xca0 [ 87.523442][ T5334] [ 87.523442][ T5334] stack backtrace: [ 87.526004][ T5334] CPU: 0 UID: 0 PID: 5334 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full) [ 87.526018][ T5334] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 87.526025][ T5334] Call Trace: [ 87.526033][ T5334] [ 87.526039][ T5334] dump_stack_lvl+0xe8/0x150 [ 87.526054][ T5334] print_circular_bug+0x2e1/0x300 [ 87.526070][ T5334] check_noncircular+0x12e/0x150 [ 87.526085][ T5334] __lock_acquire+0x1520/0x2cd0 [ 87.526098][ T5334] ? do_raw_spin_lock+0x12b/0x2f0 [ 87.526115][ T5334] ? __flush_work+0x101/0xca0 [ 87.526127][ T5334] lock_acquire+0x106/0x350 [ 87.526137][ T5334] ? __flush_work+0x101/0xca0 [ 87.526150][ T5334] ? __flush_work+0x101/0xca0 [ 87.526162][ T5334] __flush_work+0x74c/0xca0 [ 87.526173][ T5334] ? __flush_work+0x101/0xca0 [ 87.526184][ T5334] ? __flush_work+0x101/0xca0 [ 87.526196][ T5334] ? __pfx___flush_work+0x10/0x10 [ 87.526208][ T5334] ? __pfx_wq_barrier_func+0x10/0x10 [ 87.526223][ T5334] ? __cancel_work_sync+0x5c/0x110 [ 87.526235][ T5334] __cancel_work_sync+0xbe/0x110 [ 87.526248][ T5334] smc_clcsock_release+0x60/0xf0 [ 87.526304][ T5334] __smc_release+0x64e/0x7c0 [ 87.526323][ T5334] smc_close_non_accepted+0xd5/0x1f0 [ 87.526337][ T5334] smc_close_active+0xb42/0xf30 [ 87.526348][ T5334] ? __pfx_sock_def_readable+0x10/0x10 [ 87.526360][ T5334] __smc_release+0x9c/0x7c0 [ 87.526372][ T5334] ? __local_bh_enable_ip+0xd0/0x130 [ 87.526383][ T5334] smc_release+0x2c5/0x550 [ 87.526399][ T5334] sock_close+0xad/0x220 [ 87.526416][ T5334] ? __pfx_sock_close+0x10/0x10 [ 87.526432][ T5334] __fput+0x418/0xa50 [ 87.526444][ T5334] task_work_run+0x1d9/0x270 [ 87.526459][ T5334] ? __pfx_task_work_run+0x10/0x10 [ 87.526474][ T5334] exit_to_user_mode_loop+0x193/0x6b0 [ 87.526485][ T5334] ? rcu_is_watching+0x15/0xb0 [ 87.526497][ T5334] ? entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 87.526509][ T5334] do_syscall_64+0x353/0x580 [ 87.526525][ T5334] ? trace_irq_disable+0x3b/0x140 [ 87.526540][ T5334] ? clear_bhb_loop+0x40/0x90 [ 87.526552][ T5334] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 87.526563][ T5334] RIP: 0033:0x7fd5e859ce59 [ 87.526607][ T5334] 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 [ 87.526618][ T5334] RSP: 002b:00007ffecfc198a8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 [ 87.526631][ T5334] RAX: 0000000000000000 RBX: 00007fd5e8817da0 RCX: 00007fd5e859ce59 [ 87.526639][ T5334] RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 [ 87.526646][ T5334] RBP: 00007fd5e8817da0 R08: 00007fd5e8816038 R09: 0000000000000000 [ 87.526653][ T5334] R10: 0000000000df5410 R11: 0000000000000246 R12: 000000000001579d [ 87.526660][ T5334] R13: 00007fd5e8815fac R14: 00000000000154b1 R15: 00007ffecfc199b0 [ 87.526671][ T5334]