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) r3 = socket$inet_mptcp(0x2, 0x1, 0x106) connect$inet(r3, &(0x7f0000000000)={0x2, 0x4e22, @local}, 0x10) r4 = seccomp$SECCOMP_SET_MODE_FILTER_LISTENER(0x1, 0x0, &(0x7f00000000c0)={0x1, &(0x7f0000000100)=[{0x6, 0x0, 0x0, 0x7fff0006}]}) close_range(r4, 0xffffffffffffffff, 0x0) [ 79.786211][ T4667] Bluetooth: hci0: command tx timeout [ 80.052936][ T5320] [ 80.054132][ T5320] ====================================================== [ 80.057587][ T5320] WARNING: possible circular locking dependency detected [ 80.061029][ T5320] syzkaller #0 Not tainted [ 80.063078][ T5320] ------------------------------------------------------ [ 80.066234][ T5320] syz.0.0/5320 is trying to acquire lock: [ 80.069450][ T5320] ffff888042248a68 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: __flush_work+0x100/0xc50 [ 80.075053][ T5320] [ 80.075053][ T5320] but task is already holding lock: [ 80.078382][ T5320] ffff888042248ee0 (sk_lock-AF_SMC/1){+.+.}-{0:0}, at: smc_release+0x255/0x560 [ 80.082444][ T5320] [ 80.082444][ T5320] which lock already depends on the new lock. [ 80.082444][ T5320] [ 80.087609][ T5320] [ 80.087609][ T5320] the existing dependency chain (in reverse order) is: [ 80.092001][ T5320] [ 80.092001][ T5320] -> #1 (sk_lock-AF_SMC/1){+.+.}-{0:0}: [ 80.094950][ T5320] lock_sock_nested+0x48/0x100 [ 80.097251][ T5320] smc_listen_out+0x109/0x3e0 [ 80.099580][ T5320] process_scheduled_works+0xb6e/0x18c0 [ 80.102499][ T5320] worker_thread+0xa53/0xfc0 [ 80.105285][ T5320] kthread+0x388/0x470 [ 80.107284][ T5320] ret_from_fork+0x51e/0xb90 [ 80.109129][ T5320] ret_from_fork_asm+0x1a/0x30 [ 80.111453][ T5320] [ 80.111453][ T5320] -> #0 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}: [ 80.115032][ T5320] __lock_acquire+0x15a5/0x2cf0 [ 80.117466][ T5320] lock_acquire+0xf0/0x2e0 [ 80.120112][ T5320] __flush_work+0x700/0xc50 [ 80.122736][ T5320] __cancel_work_sync+0xbe/0x110 [ 80.125261][ T5320] smc_clcsock_release+0x60/0xf0 [ 80.128147][ T5320] __smc_release+0x66b/0x7e0 [ 80.130636][ T5320] smc_close_non_accepted+0xd5/0x1f0 [ 80.133528][ T5320] smc_close_active+0xb67/0xf10 [ 80.136646][ T5320] __smc_release+0x8d/0x7e0 [ 80.139114][ T5320] smc_release+0x2ce/0x560 [ 80.141352][ T5320] sock_close+0xc3/0x240 [ 80.143413][ T5320] __fput+0x44f/0xa70 [ 80.145495][ T5320] task_work_run+0x1d9/0x270 [ 80.147929][ T5320] exit_to_user_mode_loop+0xed/0x480 [ 80.150827][ T5320] do_syscall_64+0x32d/0xf80 [ 80.153706][ T5320] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 80.156713][ T5320] [ 80.156713][ T5320] other info that might help us debug this: [ 80.156713][ T5320] [ 80.160737][ T5320] Possible unsafe locking scenario: [ 80.160737][ T5320] [ 80.163812][ T5320] CPU0 CPU1 [ 80.166150][ T5320] ---- ---- [ 80.168626][ T5320] lock(sk_lock-AF_SMC/1); [ 80.170742][ T5320] lock((work_completion)(&new_smc->smc_listen_work)); [ 80.175040][ T5320] lock(sk_lock-AF_SMC/1); [ 80.178283][ T5320] lock((work_completion)(&new_smc->smc_listen_work)); [ 80.181595][ T5320] [ 80.181595][ T5320] *** DEADLOCK *** [ 80.181595][ T5320] [ 80.185055][ T5320] 3 locks held by syz.0.0/5320: [ 80.187401][ T5320] #0: ffff888046b2fb88 (&sb->s_type->i_mutex_key#14){+.+.}-{4:4}, at: sock_close+0x9b/0x240 [ 80.192508][ T5320] #1: ffff888042248ee0 (sk_lock-AF_SMC/1){+.+.}-{0:0}, at: smc_release+0x255/0x560 [ 80.197150][ T5320] #2: ffffffff8e75e5e0 (rcu_read_lock){....}-{1:3}, at: __flush_work+0x100/0xc50 [ 80.200992][ T5320] [ 80.200992][ T5320] stack backtrace: [ 80.203801][ T5320] CPU: 0 UID: 0 PID: 5320 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full) [ 80.203823][ T5320] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 80.203833][ T5320] Call Trace: [ 80.203843][ T5320] [ 80.203852][ T5320] dump_stack_lvl+0xe8/0x150 [ 80.203877][ T5320] print_circular_bug+0x2e1/0x300 [ 80.203902][ T5320] check_noncircular+0x12e/0x150 [ 80.203923][ T5320] __lock_acquire+0x15a5/0x2cf0 [ 80.203940][ T5320] ? do_raw_spin_lock+0x12b/0x2f0 [ 80.203954][ T5320] ? do_raw_spin_unlock+0x4d/0x210 [ 80.203970][ T5320] lock_acquire+0xf0/0x2e0 [ 80.203988][ T5320] ? __flush_work+0x100/0xc50 [ 80.204013][ T5320] ? __flush_work+0x100/0xc50 [ 80.204033][ T5320] __flush_work+0x700/0xc50 [ 80.204046][ T5320] ? __flush_work+0x100/0xc50 [ 80.204057][ T5320] ? __flush_work+0x100/0xc50 [ 80.204068][ T5320] ? __pfx___flush_work+0x10/0x10 [ 80.204084][ T5320] ? __lock_acquire+0x6b5/0x2cf0 [ 80.204099][ T5320] ? __pfx_wq_barrier_func+0x10/0x10 [ 80.204121][ T5320] ? __cancel_work_sync+0x5c/0x110 [ 80.204141][ T5320] __cancel_work_sync+0xbe/0x110 [ 80.204161][ T5320] smc_clcsock_release+0x60/0xf0 [ 80.204177][ T5320] __smc_release+0x66b/0x7e0 [ 80.204199][ T5320] ? __local_bh_enable_ip+0xd0/0x130 [ 80.204216][ T5320] smc_close_non_accepted+0xd5/0x1f0 [ 80.204228][ T5320] smc_close_active+0xb67/0xf10 [ 80.204242][ T5320] ? __pfx_sock_def_readable+0x10/0x10 [ 80.204260][ T5320] __smc_release+0x8d/0x7e0 [ 80.204278][ T5320] ? __local_bh_enable_ip+0xd0/0x130 [ 80.204296][ T5320] smc_release+0x2ce/0x560 [ 80.204316][ T5320] sock_close+0xc3/0x240 [ 80.204330][ T5320] ? __pfx_sock_close+0x10/0x10 [ 80.204344][ T5320] __fput+0x44f/0xa70 [ 80.204362][ T5320] task_work_run+0x1d9/0x270 [ 80.204379][ T5320] ? __pfx_task_work_run+0x10/0x10 [ 80.204393][ T5320] exit_to_user_mode_loop+0xed/0x480 [ 80.204408][ T5320] ? rcu_is_watching+0x15/0xb0 [ 80.204439][ T5320] do_syscall_64+0x32d/0xf80 [ 80.204458][ T5320] ? trace_irq_disable+0x3b/0x150 [ 80.204471][ T5320] ? entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 80.204487][ T5320] ? clear_bhb_loop+0x40/0x90 [ 80.204501][ T5320] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 80.204516][ T5320] RIP: 0033:0x7f5be8b9c819 [ 80.204533][ T5320] 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 [ 80.204547][ T5320] RSP: 002b:00007f5be9aecfe8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 [ 80.204563][ T5320] RAX: 0000000000000000 RBX: 00007f5be8e16090 RCX: 00007f5be8b9c819 [ 80.204572][ T5320] RDX: 0000000000000000 RSI: ffffffffffffffff RDI: 0000000000000000 [ 80.204579][ T5320] RBP: 00007f5be8c32c91 R08: 0000000000000000 R09: 0000000000000000 [ 80.204584][ T5320] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 [ 80.204589][ T5320] R13: 00007f5be8e16128 R14: 00007f5be8e16090 R15: 00007ffe381bc9d8 [ 80.204597][ T5320]