[ OK ] Reached target Login Prompts. [ OK ] Reached target Multi-User System. [ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... [ OK ] Started Update UTMP about System Runlevel Changes. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.0.82' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 45.803547][ C1] [ 45.806525][ C1] ======================================================== [ 45.814057][ C1] WARNING: possible irq lock inversion dependency detected [ 45.822098][ C1] 5.6.0-syzkaller #0 Not tainted [ 45.827349][ C1] -------------------------------------------------------- [ 45.835530][ C1] swapper/1/0 just changed the state of lock: [ 45.842278][ C1] ffff8880a8db5cd8 (&ctx->ctx_lock){..-.}-{2:2}, at: free_ioctx_users+0x30/0x1c0 [ 45.851409][ C1] but this lock took another, SOFTIRQ-unsafe lock in the past: [ 45.858934][ C1] (&pid->wait_pidfd){+.+.}-{2:2} [ 45.858941][ C1] [ 45.858941][ C1] [ 45.858941][ C1] and interrupts could create inverse lock ordering between them. [ 45.858941][ C1] [ 45.878566][ C1] [ 45.878566][ C1] other info that might help us debug this: [ 45.886603][ C1] Possible interrupt unsafe locking scenario: [ 45.886603][ C1] [ 45.895068][ C1] CPU0 CPU1 [ 45.900462][ C1] ---- ---- [ 45.905814][ C1] lock(&pid->wait_pidfd); [ 45.910310][ C1] local_irq_disable(); [ 45.917917][ C1] lock(&ctx->ctx_lock); [ 45.924831][ C1] lock(&pid->wait_pidfd); [ 45.931847][ C1] [ 45.935292][ C1] lock(&ctx->ctx_lock); [ 45.939768][ C1] [ 45.939768][ C1] *** DEADLOCK *** [ 45.939768][ C1] [ 45.948312][ C1] 2 locks held by swapper/1/0: [ 45.953292][ C1] #0: ffffffff892e6be0 (rcu_callback){....}-{0:0}, at: rcu_lock_acquire+0x0/0x30 [ 45.962516][ C1] #1: ffffffff892e6b90 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 [ 45.971845][ C1] [ 45.971845][ C1] the shortest dependencies between 2nd lock and 1st lock: [ 45.981313][ C1] -> (&pid->wait_pidfd){+.+.}-{2:2} { [ 45.986866][ C1] HARDIRQ-ON-W at: [ 45.990939][ C1] lock_acquire+0x169/0x480 [ 45.997267][ C1] _raw_spin_lock+0x2a/0x40 [ 46.003578][ C1] proc_pid_make_inode+0x187/0x2d0 [ 46.010580][ C1] proc_pid_instantiate+0x4b/0x1a0 [ 46.017507][ C1] proc_pid_lookup+0x218/0x2f0 [ 46.024083][ C1] proc_root_lookup+0x1b/0x50 [ 46.030786][ C1] __lookup_slow+0x240/0x370 [ 46.037186][ C1] walk_component+0x442/0x680 [ 46.043663][ C1] link_path_walk+0x66d/0xba0 [ 46.050147][ C1] path_openat+0x21d/0x38b0 [ 46.056467][ C1] do_filp_open+0x191/0x3a0 [ 46.062790][ C1] do_sys_openat2+0x463/0x770 [ 46.069290][ C1] __x64_sys_open+0x1af/0x1e0 [ 46.075782][ C1] do_syscall_64+0xf3/0x1b0 [ 46.082200][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xb3 [ 46.090272][ C1] SOFTIRQ-ON-W at: [ 46.094443][ C1] lock_acquire+0x169/0x480 [ 46.100905][ C1] _raw_spin_lock+0x2a/0x40 [ 46.107223][ C1] proc_pid_make_inode+0x187/0x2d0 [ 46.114514][ C1] proc_pid_instantiate+0x4b/0x1a0 [ 46.121741][ C1] proc_pid_lookup+0x218/0x2f0 [ 46.128331][ C1] proc_root_lookup+0x1b/0x50 [ 46.134928][ C1] __lookup_slow+0x240/0x370 [ 46.141551][ C1] walk_component+0x442/0x680 [ 46.148061][ C1] link_path_walk+0x66d/0xba0 [ 46.154992][ C1] path_openat+0x21d/0x38b0 [ 46.161441][ C1] do_filp_open+0x191/0x3a0 [ 46.168085][ C1] do_sys_openat2+0x463/0x770 [ 46.174715][ C1] __x64_sys_open+0x1af/0x1e0 [ 46.181303][ C1] do_syscall_64+0xf3/0x1b0 [ 46.187720][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xb3 [ 46.195788][ C1] INITIAL USE at: [ 46.199888][ C1] lock_acquire+0x169/0x480 [ 46.206292][ C1] _raw_spin_lock_irqsave+0x9e/0xc0 [ 46.213241][ C1] __wake_up+0xb8/0x150 [ 46.219162][ C1] do_notify_parent+0x167/0xce0 [ 46.225758][ C1] do_exit+0x12c5/0x1f80 [ 46.231713][ C1] call_usermodehelper_exec_async+0x47c/0x480 [ 46.239541][ C1] ret_from_fork+0x24/0x30 [ 46.245858][ C1] } [ 46.248474][ C1] ... key at: [] alloc_pid.__key+0x0/0x10 [ 46.256353][ C1] ... acquired at: [ 46.260234][ C1] lock_acquire+0x169/0x480 [ 46.264886][ C1] _raw_spin_lock+0x2a/0x40 [ 46.269549][ C1] io_submit_one+0x10f5/0x1a80 [ 46.274460][ C1] __se_sys_io_submit+0x117/0x220 [ 46.279989][ C1] do_syscall_64+0xf3/0x1b0 [ 46.284749][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xb3 [ 46.290882][ C1] [ 46.293208][ C1] -> (&ctx->ctx_lock){..-.}-{2:2} { [ 46.298395][ C1] IN-SOFTIRQ-W at: [ 46.302374][ C1] lock_acquire+0x169/0x480 [ 46.308504][ C1] _raw_spin_lock_irq+0x67/0x80 [ 46.315035][ C1] free_ioctx_users+0x30/0x1c0 [ 46.321618][ C1] percpu_ref_put+0x18d/0x1a0 [ 46.327925][ C1] rcu_core+0x816/0x1120 [ 46.333809][ C1] __do_softirq+0x268/0x80c [ 46.339948][ C1] irq_exit+0x223/0x230 [ 46.345727][ C1] smp_apic_timer_interrupt+0x113/0x280 [ 46.352986][ C1] apic_timer_interrupt+0xf/0x20 [ 46.359553][ C1] native_safe_halt+0xe/0x10 [ 46.365768][ C1] default_idle+0x4c/0x70 [ 46.371720][ C1] do_idle+0x1ee/0x650 [ 46.377430][ C1] cpu_startup_entry+0x15/0x20 [ 46.383832][ C1] start_secondary+0x386/0x410 [ 46.390223][ C1] secondary_startup_64+0xa4/0xb0 [ 46.396924][ C1] INITIAL USE at: [ 46.400842][ C1] lock_acquire+0x169/0x480 [ 46.407068][ C1] _raw_spin_lock_irq+0x67/0x80 [ 46.413734][ C1] io_submit_one+0x10cb/0x1a80 [ 46.420040][ C1] __se_sys_io_submit+0x117/0x220 [ 46.426611][ C1] do_syscall_64+0xf3/0x1b0 [ 46.434121][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xb3 [ 46.445350][ C1] } [ 46.447990][ C1] ... key at: [] ioctx_alloc.__key+0x0/0x10 [ 46.456092][ C1] ... acquired at: [ 46.460107][ C1] mark_lock+0x529/0x1b00 [ 46.464855][ C1] __lock_acquire+0xaa7/0x2b90 [ 46.470126][ C1] lock_acquire+0x169/0x480 [ 46.475143][ C1] _raw_spin_lock_irq+0x67/0x80 [ 46.480897][ C1] free_ioctx_users+0x30/0x1c0 [ 46.486313][ C1] percpu_ref_put+0x18d/0x1a0 [ 46.491264][ C1] rcu_core+0x816/0x1120 [ 46.495826][ C1] __do_softirq+0x268/0x80c [ 46.501390][ C1] irq_exit+0x223/0x230 [ 46.505862][ C1] smp_apic_timer_interrupt+0x113/0x280 [ 46.511584][ C1] apic_timer_interrupt+0xf/0x20 [ 46.516719][ C1] native_safe_halt+0xe/0x10 [ 46.521702][ C1] default_idle+0x4c/0x70 [ 46.526287][ C1] do_idle+0x1ee/0x650 [ 46.530649][ C1] cpu_startup_entry+0x15/0x20 [ 46.535594][ C1] start_secondary+0x386/0x410 [ 46.540510][ C1] secondary_startup_64+0xa4/0xb0 [ 46.545831][ C1] [ 46.548163][ C1] [ 46.548163][ C1] stack backtrace: [ 46.554900][ C1] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.6.0-syzkaller #0 [ 46.562421][ C1] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 46.572478][ C1] Call Trace: [ 46.575746][ C1] [ 46.578596][ C1] dump_stack+0x1e9/0x30e [ 46.582928][ C1] print_irq_inversion_bug+0xb67/0xe90 [ 46.588375][ C1] ? arch_stack_walk+0xb4/0xe0 [ 46.593303][ C1] ? secondary_startup_64+0xa4/0xb0 [ 46.598578][ C1] check_usage_forwards+0x13f/0x240 [ 46.604289][ C1] ? save_trace+0x49/0xb60 [ 46.608766][ C1] mark_lock+0x529/0x1b00 [ 46.613087][ C1] ? check_usage_backwards+0x240/0x240 [ 46.618605][ C1] ? mark_lock+0x102/0x1b00 [ 46.623112][ C1] ? __lock_acquire+0x116c/0x2b90 [ 46.628213][ C1] __lock_acquire+0xaa7/0x2b90 [ 46.633142][ C1] ? pcpu_block_update+0x564/0x890 [ 46.638419][ C1] lock_acquire+0x169/0x480 [ 46.643187][ C1] ? free_ioctx_users+0x30/0x1c0 [ 46.648100][ C1] ? rcu_lock_acquire+0x5/0x30 [ 46.652854][ C1] ? trace_irq_disable_rcuidle+0x1f/0x1d0 [ 46.658675][ C1] ? percpu_ref_noop_confirm_switch+0x10/0x10 [ 46.664728][ C1] _raw_spin_lock_irq+0x67/0x80 [ 46.669640][ C1] ? free_ioctx_users+0x30/0x1c0 [ 46.674555][ C1] free_ioctx_users+0x30/0x1c0 [ 46.679373][ C1] ? percpu_ref_noop_confirm_switch+0x10/0x10 [ 46.685433][ C1] ? percpu_ref_noop_confirm_switch+0x10/0x10 [ 46.692545][ C1] percpu_ref_put+0x18d/0x1a0 [ 46.697278][ C1] rcu_core+0x816/0x1120 [ 46.701544][ C1] __do_softirq+0x268/0x80c [ 46.706070][ C1] ? irq_exit+0x223/0x230 [ 46.710455][ C1] irq_exit+0x223/0x230 [ 46.714626][ C1] smp_apic_timer_interrupt+0x113/0x280 [ 46.720167][ C1] apic_timer_interrupt+0xf/0x20 [ 46.725098][ C1] [ 46.728025][ C1] RIP: 0010:native_safe_halt+0xe/0x10 [ 46.733370][ C1] Code: 80 e1 07 80 c1 03 38 c1 7c bc 48 89 df e8 7a fe a7 f9 eb b2 cc cc cc cc cc cc cc cc e9 07 00 00 00 0f 00 2d a6 eb 56 00 fb f4 90 e9 07 00 00 00 0f 00 2d 96 eb 56 00 f4 c3 cc cc 41 56 53 65 [ 46.752954][ C1] RSP: 0018:ffffc90000d3fe60 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 [ 46.761512][ C1] RAX: 1ffffffff1257401 RBX: ffff8880a9a3c340 RCX: dffffc0000000000 [ 46.769470][ C1] RDX: dffffc0000000000 RSI: 0000000000000000 RDI: ffff8880a9a3cba4 [ 46.777425][ C1] RBP: ffffffff896b98e0 R08: ffffffff817b9a70 R09: ffffed1015347869 [ 46.785388][ C1] R10: ffffed1015347869 R11: 0000000000000000 R12: 1ffff11015347868 [ 46.793400][ C1] R13: dffffc0000000000 R14: 1ffffffff12573ff R15: 0000000000000001 [ 46.801556][ C1] ? trace_hardirqs_on+0x30/0x70 [ 46.806498][