program: r0 = socket$inet6_tcp(0xa, 0x1, 0x0) r1 = socket$nl_generic(0x10, 0x3, 0x10) r2 = syz_genetlink_get_family_id$smc(&(0x7f00000033c0), 0xffffffffffffffff) sendmsg$SMC_PNETID_ADD(r1, &(0x7f0000000180)={0x0, 0x0, &(0x7f0000000100)={&(0x7f0000000300)={0x34, r2, 0x1, 0x70bd2b, 0x25dfdbfd, {}, [@SMC_PNETID_NAME={0x9, 0x1, 'syz2\x00'}, @SMC_PNETID_ETHNAME={0x14, 0x2, 'lo\x00'}]}, 0x34}}, 0x804) close(r0) socket(0x2b, 0x1, 0x1) bind$inet6(r0, &(0x7f0000000040)={0xa, 0x4e22, 0x0, @empty}, 0x1c) listen(r0, 0x0) r3 = socket$inet_smc(0x2b, 0x1, 0x0) connect$inet(r3, &(0x7f0000000000)={0x2, 0x4e22, @local}, 0x10) [ 83.934980][ T5301] Bluetooth: hci0: command tx timeout [ 84.032150][ T5321] smc: net device lo applied user defined pnetid SYZ2 [ 84.079541][ T5320] [ 84.080692][ T5320] ====================================================== [ 84.084150][ T5320] WARNING: possible circular locking dependency detected [ 84.087948][ T5320] syzkaller #0 Not tainted [ 84.090582][ T5320] ------------------------------------------------------ [ 84.093672][ T5320] syz.0.0/5320 is trying to acquire lock: [ 84.096462][ T5320] ffff888011b88a68 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: __flush_work+0x100/0xc50 [ 84.102328][ T5320] [ 84.102328][ T5320] but task is already holding lock: [ 84.105817][ T5320] ffff888011b88ee0 (sk_lock-AF_SMC/1){+.+.}-{0:0}, at: smc_release+0x255/0x560 [ 84.109942][ T5320] [ 84.109942][ T5320] which lock already depends on the new lock. [ 84.109942][ T5320] [ 84.115403][ T5320] [ 84.115403][ T5320] the existing dependency chain (in reverse order) is: [ 84.119677][ T5320] [ 84.119677][ T5320] -> #1 (sk_lock-AF_SMC/1){+.+.}-{0:0}: [ 84.123197][ T5320] lock_sock_nested+0x48/0x100 [ 84.125563][ T5320] smc_listen_out+0x109/0x3e0 [ 84.128423][ T5320] smc_listen_work+0x813/0x13f0 [ 84.132308][ T5320] process_scheduled_works+0xb02/0x1830 [ 84.135681][ T5320] worker_thread+0xa50/0xfc0 [ 84.138066][ T5320] kthread+0x388/0x470 [ 84.140389][ T5320] ret_from_fork+0x51e/0xb90 [ 84.142830][ T5320] ret_from_fork_asm+0x1a/0x30 [ 84.145219][ T5320] [ 84.145219][ T5320] -> #0 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}: [ 84.150012][ T5320] __lock_acquire+0x15a5/0x2cf0 [ 84.152608][ T5320] lock_acquire+0xf0/0x2e0 [ 84.155223][ T5320] __flush_work+0x700/0xc50 [ 84.157718][ T5320] __cancel_work_sync+0xbe/0x110 [ 84.161222][ T5320] smc_clcsock_release+0x60/0xf0 [ 84.164384][ T5320] __smc_release+0x66b/0x7e0 [ 84.167078][ T5320] smc_close_non_accepted+0xd5/0x1f0 [ 84.169856][ T5320] smc_close_active+0xb67/0xf10 [ 84.172412][ T5320] __smc_release+0x8d/0x7e0 [ 84.174782][ T5320] smc_release+0x2ce/0x560 [ 84.177148][ T5320] sock_close+0xc3/0x240 [ 84.179701][ T5320] __fput+0x44f/0xa70 [ 84.182107][ T5320] task_work_run+0x1d9/0x270 [ 84.184901][ T5320] exit_to_user_mode_loop+0xed/0x480 [ 84.187376][ T5320] do_syscall_64+0x32d/0xf80 [ 84.189659][ T5320] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 84.192935][ T5320] [ 84.192935][ T5320] other info that might help us debug this: [ 84.192935][ T5320] [ 84.198368][ T5320] Possible unsafe locking scenario: [ 84.198368][ T5320] [ 84.202207][ T5320] CPU0 CPU1 [ 84.204688][ T5320] ---- ---- [ 84.207108][ T5320] lock(sk_lock-AF_SMC/1); [ 84.209230][ T5320] lock((work_completion)(&new_smc->smc_listen_work)); [ 84.214917][ T5320] lock(sk_lock-AF_SMC/1); [ 84.219109][ T5320] lock((work_completion)(&new_smc->smc_listen_work)); [ 84.222229][ T5320] [ 84.222229][ T5320] *** DEADLOCK *** [ 84.222229][ T5320] [ 84.225686][ T5320] 3 locks held by syz.0.0/5320: [ 84.227962][ T5320] #0: ffff888047a46488 (&sb->s_type->i_mutex_key#14){+.+.}-{4:4}, at: sock_close+0x9b/0x240 [ 84.233791][ T5320] #1: ffff888011b88ee0 (sk_lock-AF_SMC/1){+.+.}-{0:0}, at: smc_release+0x255/0x560 [ 84.238373][ T5320] #2: ffffffff8e75e420 (rcu_read_lock){....}-{1:3}, at: __flush_work+0x100/0xc50 [ 84.242060][ T5320] [ 84.242060][ T5320] stack backtrace: [ 84.244561][ T5320] CPU: 0 UID: 0 PID: 5320 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full) [ 84.244580][ T5320] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 84.244586][ T5320] Call Trace: [ 84.244596][ T5320] [ 84.244603][ T5320] dump_stack_lvl+0xe8/0x150 [ 84.244623][ T5320] print_circular_bug+0x2e1/0x300 [ 84.244640][ T5320] check_noncircular+0x12e/0x150 [ 84.244656][ T5320] __lock_acquire+0x15a5/0x2cf0 [ 84.244669][ T5320] ? do_raw_spin_lock+0x12b/0x2f0 [ 84.244681][ T5320] ? do_raw_spin_unlock+0x4d/0x210 [ 84.244692][ T5320] lock_acquire+0xf0/0x2e0 [ 84.244704][ T5320] ? __flush_work+0x100/0xc50 [ 84.244721][ T5320] ? __flush_work+0x100/0xc50 [ 84.244734][ T5320] __flush_work+0x700/0xc50 [ 84.244747][ T5320] ? __flush_work+0x100/0xc50 [ 84.244760][ T5320] ? __flush_work+0x100/0xc50 [ 84.244776][ T5320] ? __pfx___flush_work+0x10/0x10 [ 84.244789][ T5320] ? __pfx_wq_barrier_func+0x10/0x10 [ 84.244805][ T5320] ? __cancel_work_sync+0x5c/0x110 [ 84.244821][ T5320] __cancel_work_sync+0xbe/0x110 [ 84.244835][ T5320] smc_clcsock_release+0x60/0xf0 [ 84.244852][ T5320] __smc_release+0x66b/0x7e0 [ 84.244866][ T5320] ? __local_bh_enable_ip+0xd0/0x130 [ 84.244879][ T5320] smc_close_non_accepted+0xd5/0x1f0 [ 84.244893][ T5320] smc_close_active+0xb67/0xf10 [ 84.244908][ T5320] ? __pfx_sock_def_readable+0x10/0x10 [ 84.244921][ T5320] __smc_release+0x8d/0x7e0 [ 84.244938][ T5320] ? __local_bh_enable_ip+0xd0/0x130 [ 84.244951][ T5320] smc_release+0x2ce/0x560 [ 84.244965][ T5320] sock_close+0xc3/0x240 [ 84.244975][ T5320] ? __pfx_sock_close+0x10/0x10 [ 84.244984][ T5320] __fput+0x44f/0xa70 [ 84.245000][ T5320] task_work_run+0x1d9/0x270 [ 84.245012][ T5320] ? __pfx_task_work_run+0x10/0x10 [ 84.245025][ T5320] exit_to_user_mode_loop+0xed/0x480 [ 84.245037][ T5320] ? rcu_is_watching+0x15/0xb0 [ 84.245052][ T5320] do_syscall_64+0x32d/0xf80 [ 84.245069][ T5320] ? trace_irq_disable+0x3b/0x150 [ 84.245086][ T5320] ? entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 84.245096][ T5320] ? clear_bhb_loop+0x40/0x90 [ 84.245107][ T5320] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 84.245118][ T5320] RIP: 0033:0x7fe0df59c799 [ 84.245130][ 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 [ 84.245139][ T5320] RSP: 002b:00007ffe7f990418 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 [ 84.245152][ T5320] RAX: 0000000000000000 RBX: 00007ffe7f990500 RCX: 00007fe0df59c799 [ 84.245159][ T5320] RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 [ 84.245165][ T5320] RBP: 0000000000014785 R08: 0000000000000001 R09: 0000000000000000 [ 84.245171][ T5320] R10: 00007fe0df3ff040 R11: 0000000000000246 R12: 00007ffe7f990540 [ 84.245177][ T5320] R13: 00007fe0df815fac R14: 00000000000147e0 R15: 00007fe0df815fa0 [ 84.245187][ T5320]