Warning: Permanently added '10.128.0.66' (ECDSA) to the list of known hosts. syzkaller login: [ 60.550735][ T6861] IPVS: ftp: loaded support on port[0] = 21 [ 60.560976][ T6864] IPVS: ftp: loaded support on port[0] = 21 [ 60.575859][ T6860] IPVS: ftp: loaded support on port[0] = 21 [ 60.575899][ T6865] IPVS: ftp: loaded support on port[0] = 21 [ 60.583410][ T6862] IPVS: ftp: loaded support on port[0] = 21 [ 60.587973][ T6863] IPVS: ftp: loaded support on port[0] = 21 executing program executing program executing program executing program executing program executing program executing program executing program [ 60.863455][ T7010] [ 60.865812][ T7010] ============================================ [ 60.871946][ T7010] WARNING: possible recursive locking detected [ 60.878087][ T7010] 5.9.0-rc2-syzkaller #0 Not tainted [ 60.883358][ T7010] -------------------------------------------- [ 60.889517][ T7010] syz-executor339/7010 is trying to acquire lock: [ 60.895896][ T7010] ffff888094030058 (&sighand->siglock){....}-{2:2}, at: __lock_task_sighand+0x106/0x2d0 [ 60.905586][ T7010] [ 60.905586][ T7010] but task is already holding lock: [ 60.912950][ T7010] ffff888094030058 (&sighand->siglock){....}-{2:2}, at: force_sig_info_to_task+0x6c/0x3a0 [ 60.922819][ T7010] [ 60.922819][ T7010] other info that might help us debug this: [ 60.930854][ T7010] Possible unsafe locking scenario: [ 60.930854][ T7010] [ 60.938284][ T7010] CPU0 [ 60.941548][ T7010] ---- [ 60.944794][ T7010] lock(&sighand->siglock); [ 60.949349][ T7010] lock(&sighand->siglock); [ 60.953909][ T7010] [ 60.953909][ T7010] *** DEADLOCK *** [ 60.953909][ T7010] [ 60.962020][ T7010] May be due to missing lock nesting notation [ 60.962020][ T7010] [ 60.970397][ T7010] 3 locks held by syz-executor339/7010: [ 60.975903][ T7010] #0: ffff888094030058 (&sighand->siglock){....}-{2:2}, at: force_sig_info_to_task+0x6c/0x3a0 [ 60.986223][ T7010] #1: ffff8880940300a0 (&sighand->signalfd_wqh){....}-{2:2}, at: __wake_up_common_lock+0xb4/0x130 [ 60.996876][ T7010] #2: ffffffff89bd6900 (rcu_read_lock){....}-{1:2}, at: __lock_task_sighand+0x0/0x2d0 [ 61.006495][ T7010] [ 61.006495][ T7010] stack backtrace: [ 61.012356][ T7010] CPU: 1 PID: 7010 Comm: syz-executor339 Not tainted 5.9.0-rc2-syzkaller #0 [ 61.020994][ T7010] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 61.031027][ T7010] Call Trace: [ 61.034295][ T7010] dump_stack+0x18f/0x20d [ 61.038617][ T7010] __lock_acquire.cold+0x115/0x396 [ 61.043700][ T7010] ? lockdep_hardirqs_on_prepare+0x530/0x530 [ 61.049651][ T7010] ? lockdep_hardirqs_on_prepare+0x530/0x530 [ 61.055618][ T7010] lock_acquire+0x1f1/0xad0 [ 61.060121][ T7010] ? __lock_task_sighand+0x106/0x2d0 [ 61.065375][ T7010] ? lock_release+0x8e0/0x8e0 [ 61.070020][ T7010] ? lock_release+0x8e0/0x8e0 [ 61.074669][ T7010] ? lockdep_hardirqs_on_prepare+0x530/0x530 [ 61.080620][ T7010] ? __lock_acquire+0x2e85/0x5640 [ 61.085618][ T7010] _raw_spin_lock_irqsave+0x8c/0xc0 [ 61.090785][ T7010] ? __lock_task_sighand+0x106/0x2d0 [ 61.096037][ T7010] __lock_task_sighand+0x106/0x2d0 [ 61.101129][ T7010] ? __io_async_wake+0x34f/0x980 [ 61.106033][ T7010] task_work_add+0x1d7/0x290 [ 61.110591][ T7010] ? cpumask_weight.constprop.0+0x3f/0x3f [ 61.116293][ T7010] ? lock_is_held_type+0xbb/0xf0 [ 61.121212][ T7010] __io_async_wake+0x415/0x980 [ 61.125943][ T7010] ? io_async_wake+0xd8/0x3c0 [ 61.130589][ T7010] ? io_req_task_submit+0x240/0x240 [ 61.135767][ T7010] __wake_up_common+0x147/0x650 [ 61.140588][ T7010] __wake_up_common_lock+0xd0/0x130 [ 61.145756][ T7010] ? __wake_up_common+0x650/0x650 [ 61.150750][ T7010] ? __sigqueue_alloc+0x236/0x550 [ 61.155755][ T7010] ? rcu_read_lock_sched_held+0x3a/0xb0 [ 61.161269][ T7010] ? __sigqueue_alloc+0x2e4/0x550 [ 61.166262][ T7010] __send_signal+0x75b/0xf90 [ 61.170823][ T7010] force_sig_info_to_task+0x2a0/0x3a0 [ 61.176173][ T7010] force_sig_fault+0xb0/0xf0 [ 61.180732][ T7010] ? force_sig_fault_to_task+0xe0/0xe0 [ 61.186160][ T7010] ? arch_local_irq_disable+0x50/0x50 [ 61.191501][ T7010] ? _down_write_nest_lock+0x150/0x150 [ 61.196940][ T7010] __bad_area_nosemaphore+0x32a/0x480 [ 61.202283][ T7010] do_user_addr_fault+0x852/0xbf0 [ 61.207288][ T7010] ? rcu_read_lock_sched_held+0x3a/0xb0 [ 61.212806][ T7010] exc_page_fault+0xa8/0x160 [ 61.217385][ T7010] ? asm_exc_page_fault+0x8/0x30 [ 61.222301][ T7010] asm_exc_page_fault+0x1e/0x30 [ 61.227130][ T7010] RIP: 0033:0x4013f9 [ 61.231008][ T7010] Code: 00 20 00 c6 04 25 3d 02 00 20 00 c6 04 25 3e 02 00 20 00 c6 04 25 3f 02 00 20 00 48 8b 15 a7 ac 2d 00 48 8b 34 25 00 02 00 20 <8b> 8a 0c 01 00 00 48 89 30 48 8b 34 25 08 02 00 20 c1 e1 04 48 89 [ 61.250597][ T7010] RSP: 002b:00007f8507d67d10 EFLAGS: 00010246 [ 61.256646][ T7010] RAX: ffffffffffffffff RBX: 00000000006f0038 RCX: 0000000000000000 [ 61.264593][ T7010] RDX: ffffffffffffffff RSI: 0000000600000002 RDI: 0000000000000000 [ 61.272553][ T7010] RBP: 00000000006f0030 R08: 0000000000000000 R09: 0000000000000000 [ 61.280508][ T7010] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006f003c [ 61.288465][ T7010] R13: 00007f8507d67d10 R14: 00007f8507d67d10 R15: 0000000000000001