[ 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 '10.128.0.55' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 41.880551][ C0] [ 41.882938][ C0] ======================================================== [ 41.890233][ C0] WARNING: possible irq lock inversion dependency detected [ 41.897403][ C0] 5.6.0-syzkaller #0 Not tainted [ 41.902310][ C0] -------------------------------------------------------- [ 41.909590][ C0] swapper/0/0 just changed the state of lock: [ 41.915629][ C0] ffff8880a80cfcd8 (&ctx->ctx_lock){..-.}-{2:2}, at: free_ioctx_users+0x30/0x1c0 [ 41.924763][ C0] but this lock took another, SOFTIRQ-unsafe lock in the past: [ 41.932274][ C0] (&pid->wait_pidfd){+.+.}-{2:2} [ 41.932280][ C0] [ 41.932280][ C0] [ 41.932280][ C0] and interrupts could create inverse lock ordering between them. [ 41.932280][ C0] [ 41.951602][ C0] [ 41.951602][ C0] other info that might help us debug this: [ 41.959649][ C0] Possible interrupt unsafe locking scenario: [ 41.959649][ C0] [ 41.967936][ C0] CPU0 CPU1 [ 41.973289][ C0] ---- ---- [ 41.978626][ C0] lock(&pid->wait_pidfd); [ 41.983106][ C0] local_irq_disable(); [ 41.989889][ C0] lock(&ctx->ctx_lock); [ 41.997351][ C0] lock(&pid->wait_pidfd); [ 42.004348][ C0] [ 42.007834][ C0] lock(&ctx->ctx_lock); [ 42.012352][ C0] [ 42.012352][ C0] *** DEADLOCK *** [ 42.012352][ C0] [ 42.020472][ C0] 2 locks held by swapper/0/0: [ 42.025205][ C0] #0: ffffffff892e6be0 (rcu_callback){....}-{0:0}, at: rcu_lock_acquire+0x0/0x30 [ 42.034389][ C0] #1: ffffffff892e6b90 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 [ 42.043720][ C0] [ 42.043720][ C0] the shortest dependencies between 2nd lock and 1st lock: [ 42.053080][ C0] -> (&pid->wait_pidfd){+.+.}-{2:2} { [ 42.058514][ C0] HARDIRQ-ON-W at: [ 42.062624][ C0] lock_acquire+0x169/0x480 [ 42.069012][ C0] _raw_spin_lock+0x2a/0x40 [ 42.075426][ C0] proc_pid_make_inode+0x187/0x2d0 [ 42.082434][ C0] proc_pid_instantiate+0x4b/0x1a0 [ 42.089389][ C0] proc_pid_lookup+0x218/0x2f0 [ 42.095946][ C0] proc_root_lookup+0x1b/0x50 [ 42.102415][ C0] __lookup_slow+0x240/0x370 [ 42.108798][ C0] walk_component+0x442/0x680 [ 42.115290][ C0] link_path_walk+0x66d/0xba0 [ 42.121765][ C0] path_openat+0x21d/0x38b0 [ 42.128064][ C0] do_filp_open+0x191/0x3a0 [ 42.134360][ C0] do_sys_openat2+0x463/0x770 [ 42.140877][ C0] __x64_sys_open+0x1af/0x1e0 [ 42.147349][ C0] do_syscall_64+0xf3/0x1b0 [ 42.153648][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xb3 [ 42.161330][ C0] SOFTIRQ-ON-W at: [ 42.165370][ C0] lock_acquire+0x169/0x480 [ 42.171665][ C0] _raw_spin_lock+0x2a/0x40 [ 42.177974][ C0] proc_pid_make_inode+0x187/0x2d0 [ 42.184882][ C0] proc_pid_instantiate+0x4b/0x1a0 [ 42.191788][ C0] proc_pid_lookup+0x218/0x2f0 [ 42.198361][ C0] proc_root_lookup+0x1b/0x50 [ 42.204847][ C0] __lookup_slow+0x240/0x370 [ 42.211232][ C0] walk_component+0x442/0x680 [ 42.218136][ C0] link_path_walk+0x66d/0xba0 [ 42.225658][ C0] path_openat+0x21d/0x38b0 [ 42.231951][ C0] do_filp_open+0x191/0x3a0 [ 42.238245][ C0] do_sys_openat2+0x463/0x770 [ 42.244731][ C0] __x64_sys_open+0x1af/0x1e0 [ 42.251202][ C0] do_syscall_64+0xf3/0x1b0 [ 42.257509][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xb3 [ 42.265190][ C0] INITIAL USE at: [ 42.269144][ C0] lock_acquire+0x169/0x480 [ 42.275353][ C0] _raw_spin_lock_irqsave+0x9e/0xc0 [ 42.282265][ C0] __wake_up+0xb8/0x150 [ 42.288127][ C0] do_notify_parent+0x167/0xce0 [ 42.294696][ C0] do_exit+0x12c5/0x1f80 [ 42.300659][ C0] call_usermodehelper_exec_async+0x47c/0x480 [ 42.308461][ C0] ret_from_fork+0x24/0x30 [ 42.314593][ C0] } [ 42.317165][ C0] ... key at: [] alloc_pid.__key+0x0/0x10 [ 42.325023][ C0] ... acquired at: [ 42.328896][ C0] lock_acquire+0x169/0x480 [ 42.333555][ C0] _raw_spin_lock+0x2a/0x40 [ 42.338212][ C0] io_submit_one+0x10f5/0x1a80 [ 42.343305][ C0] __se_sys_io_submit+0x117/0x220 [ 42.348473][ C0] do_syscall_64+0xf3/0x1b0 [ 42.353133][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xb3 [ 42.360640][ C0] [ 42.362947][ C0] -> (&ctx->ctx_lock){..-.}-{2:2} { [ 42.368123][ C0] IN-SOFTIRQ-W at: [ 42.372082][ C0] lock_acquire+0x169/0x480 [ 42.378209][ C0] _raw_spin_lock_irq+0x67/0x80 [ 42.384702][ C0] free_ioctx_users+0x30/0x1c0 [ 42.391100][ C0] percpu_ref_put+0x18d/0x1a0 [ 42.397414][ C0] rcu_core+0x816/0x1120 [ 42.403308][ C0] __do_softirq+0x268/0x80c [ 42.411446][ C0] irq_exit+0x223/0x230 [ 42.417217][ C0] smp_apic_timer_interrupt+0x113/0x280 [ 42.424823][ C0] apic_timer_interrupt+0xf/0x20 [ 42.431380][ C0] native_safe_halt+0xe/0x10 [ 42.437601][ C0] default_idle+0x4c/0x70 [ 42.443559][ C0] do_idle+0x1ee/0x650 [ 42.449256][ C0] cpu_startup_entry+0x15/0x20 [ 42.455640][ C0] start_kernel+0x674/0x774 [ 42.461768][ C0] secondary_startup_64+0xa4/0xb0 [ 42.468565][ C0] INITIAL USE at: [ 42.472457][ C0] lock_acquire+0x169/0x480 [ 42.478498][ C0] _raw_spin_lock_irq+0x67/0x80 [ 42.484883][ C0] io_submit_one+0x10cb/0x1a80 [ 42.491180][ C0] __se_sys_io_submit+0x117/0x220 [ 42.497854][ C0] do_syscall_64+0xf3/0x1b0 [ 42.503896][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xb3 [ 42.511321][ C0] } [ 42.513802][ C0] ... key at: [] ioctx_alloc.__key+0x0/0x10 [ 42.521756][ C0] ... acquired at: [ 42.525548][ C0] mark_lock+0x529/0x1b00 [ 42.530019][ C0] __lock_acquire+0xaa7/0x2b90 [ 42.534960][ C0] lock_acquire+0x169/0x480 [ 42.539606][ C0] _raw_spin_lock_irq+0x67/0x80 [ 42.544615][ C0] free_ioctx_users+0x30/0x1c0 [ 42.549526][ C0] percpu_ref_put+0x18d/0x1a0 [ 42.554379][ C0] rcu_core+0x816/0x1120 [ 42.558794][ C0] __do_softirq+0x268/0x80c [ 42.563463][ C0] irq_exit+0x223/0x230 [ 42.567779][ C0] smp_apic_timer_interrupt+0x113/0x280 [ 42.573593][ C0] apic_timer_interrupt+0xf/0x20 [ 42.578677][ C0] native_safe_halt+0xe/0x10 [ 42.583426][ C0] default_idle+0x4c/0x70 [ 42.588004][ C0] do_idle+0x1ee/0x650 [ 42.592220][ C0] cpu_startup_entry+0x15/0x20 [ 42.597130][ C0] start_kernel+0x674/0x774 [ 42.601785][ C0] secondary_startup_64+0xa4/0xb0 [ 42.606960][ C0] [ 42.609261][ C0] [ 42.609261][ C0] stack backtrace: [ 42.615142][ C0] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.6.0-syzkaller #0 [ 42.622654][ C0] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 42.632683][ C0] Call Trace: [ 42.635937][ C0] [ 42.638861][ C0] dump_stack+0x1e9/0x30e [ 42.643162][ C0] print_irq_inversion_bug+0xb67/0xe90 [ 42.648624][ C0] ? arch_stack_walk+0xb4/0xe0 [ 42.653359][ C0] ? secondary_startup_64+0xa4/0xb0 [ 42.658537][ C0] check_usage_forwards+0x13f/0x240 [ 42.663719][ C0] ? save_trace+0x49/0xb60 [ 42.668105][ C0] mark_lock+0x529/0x1b00 [ 42.672404][ C0] ? check_usage_backwards+0x240/0x240 [ 42.680175][ C0] ? mark_lock+0x102/0x1b00 [ 42.684649][ C0] ? __lock_acquire+0x116c/0x2b90 [ 42.689643][ C0] __lock_acquire+0xaa7/0x2b90 [ 42.694387][ C0] ? pcpu_block_update+0x564/0x890 [ 42.699466][ C0] lock_acquire+0x169/0x480 [ 42.703938][ C0] ? free_ioctx_users+0x30/0x1c0 [ 42.708848][ C0] ? rcu_lock_acquire+0x5/0x30 [ 42.713580][ C0] ? trace_irq_disable_rcuidle+0x1f/0x1d0 [ 42.719270][ C0] ? percpu_ref_noop_confirm_switch+0x10/0x10 [ 42.725308][ C0] _raw_spin_lock_irq+0x67/0x80 [ 42.730129][ C0] ? free_ioctx_users+0x30/0x1c0 [ 42.735121][ C0] free_ioctx_users+0x30/0x1c0 [ 42.739853][ C0] ? percpu_ref_noop_confirm_switch+0x10/0x10 [ 42.745890][ C0] ? percpu_ref_noop_confirm_switch+0x10/0x10 [ 42.751925][ C0] percpu_ref_put+0x18d/0x1a0 [ 42.756569][ C0] rcu_core+0x816/0x1120 [ 42.760801][ C0] __do_softirq+0x268/0x80c [ 42.765285][ C0] ? irq_exit+0x223/0x230 [ 42.769659][ C0] irq_exit+0x223/0x230 [ 42.773833][ C0] smp_apic_timer_interrupt+0x113/0x280 [ 42.779437][ C0] apic_timer_interrupt+0xf/0x20 [ 42.784343][ C0] [ 42.787254][ C0] RIP: 0010:native_safe_halt+0xe/0x10 [ 42.792596][ C0] 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 [ 42.812168][ C0] RSP: 0018:ffffffff89207e68 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 [ 42.820559][ C0] RAX: 1ffffffff1257401 RBX: ffffffff89281b00 RCX: dffffc0000000000 [ 42.828506][ C0] RDX: dffffc0000000000 RSI: 0000000000000000 RDI: ffffffff89282364 [ 42.836448][ C0] RBP: ffffffff896b98e0 R08: ffffffff817b9a70 R09: fffffbfff1250361 [ 42.844390][ C0] R10: fffffbfff1250361 R11: 0000000000000000 R12: 1ffffffff1250360 [ 42.852333][ C0] R13: dffffc0000000000 R14: 1ffffffff12573ff R15: 0000000000000000 [ 42.860340][ C0] ? trace_hardirqs_on+0x30/0x70 [ 42.865318][ C0] default_idle+0x4c/0x70 [ 42.869660][ C0] do_idle+0x1ee/0x650 [ 42.873709][ C0] cpu_startup_entry+0x15/0x20 [ 42.878499][ C0] ? time_init+0x33/0x33 [ 42.882715][ C0] start_kernel+0x674/0x774 [ 42.887195][ C0] secondary_startup_64+0xa4/0xb0