[ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... Starting Load/Save RF Kill Switch Status... [ OK ] Started Update UTMP about System Runlevel Changes. [ OK ] Started Load/Save RF Kill Switch Status. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.0.181' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 42.983208][ C1] [ 42.985675][ C1] ======================================================== [ 42.992876][ C1] WARNING: possible irq lock inversion dependency detected [ 43.000153][ C1] 5.6.0-syzkaller #0 Not tainted [ 43.005067][ C1] -------------------------------------------------------- [ 43.012250][ C1] swapper/1/0 just changed the state of lock: [ 43.018486][ C1] ffff88809d7e5cd8 (&ctx->ctx_lock){..-.}-{2:2}, at: free_ioctx_users+0x30/0x1c0 [ 43.027584][ C1] but this lock took another, SOFTIRQ-unsafe lock in the past: [ 43.035110][ C1] (&pid->wait_pidfd){+.+.}-{2:2} [ 43.035116][ C1] [ 43.035116][ C1] [ 43.035116][ C1] and interrupts could create inverse lock ordering between them. [ 43.035116][ C1] [ 43.054523][ C1] [ 43.054523][ C1] other info that might help us debug this: [ 43.062586][ C1] Possible interrupt unsafe locking scenario: [ 43.062586][ C1] [ 43.070879][ C1] CPU0 CPU1 [ 43.076221][ C1] ---- ---- [ 43.081578][ C1] lock(&pid->wait_pidfd); [ 43.086049][ C1] local_irq_disable(); [ 43.092806][ C1] lock(&ctx->ctx_lock); [ 43.099886][ C1] lock(&pid->wait_pidfd); [ 43.106901][ C1] [ 43.110509][ C1] lock(&ctx->ctx_lock); [ 43.114996][ C1] [ 43.114996][ C1] *** DEADLOCK *** [ 43.114996][ C1] [ 43.123216][ C1] 2 locks held by swapper/1/0: [ 43.127944][ C1] #0: ffffffff892e6c20 (rcu_callback){....}-{0:0}, at: rcu_lock_acquire+0x0/0x30 [ 43.137126][ C1] #1: ffffffff892e6bd0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 [ 43.146382][ C1] [ 43.146382][ C1] the shortest dependencies between 2nd lock and 1st lock: [ 43.155729][ C1] -> (&pid->wait_pidfd){+.+.}-{2:2} { [ 43.161324][ C1] HARDIRQ-ON-W at: [ 43.165393][ C1] lock_acquire+0x169/0x480 [ 43.171707][ C1] _raw_spin_lock+0x2a/0x40 [ 43.178016][ C1] proc_pid_make_inode+0x187/0x2d0 [ 43.184937][ C1] proc_pid_instantiate+0x4b/0x1a0 [ 43.191854][ C1] proc_pid_lookup+0x218/0x2f0 [ 43.198683][ C1] proc_root_lookup+0x1b/0x50 [ 43.205159][ C1] __lookup_slow+0x240/0x370 [ 43.211553][ C1] walk_component+0x442/0x680 [ 43.218043][ C1] link_path_walk+0x66d/0xba0 [ 43.224598][ C1] path_openat+0x21d/0x38b0 [ 43.230892][ C1] do_filp_open+0x191/0x3a0 [ 43.238067][ C1] do_sys_openat2+0x463/0x770 [ 43.244544][ C1] __x64_sys_open+0x1af/0x1e0 [ 43.251016][ C1] do_syscall_64+0xf3/0x1b0 [ 43.257410][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xb3 [ 43.265099][ C1] SOFTIRQ-ON-W at: [ 43.269153][ C1] lock_acquire+0x169/0x480 [ 43.275466][ C1] _raw_spin_lock+0x2a/0x40 [ 43.281871][ C1] proc_pid_make_inode+0x187/0x2d0 [ 43.288775][ C1] proc_pid_instantiate+0x4b/0x1a0 [ 43.295707][ C1] proc_pid_lookup+0x218/0x2f0 [ 43.302264][ C1] proc_root_lookup+0x1b/0x50 [ 43.309534][ C1] __lookup_slow+0x240/0x370 [ 43.316095][ C1] walk_component+0x442/0x680 [ 43.322591][ C1] link_path_walk+0x66d/0xba0 [ 43.329077][ C1] path_openat+0x21d/0x38b0 [ 43.335386][ C1] do_filp_open+0x191/0x3a0 [ 43.341686][ C1] do_sys_openat2+0x463/0x770 [ 43.348166][ C1] __x64_sys_open+0x1af/0x1e0 [ 43.354643][ C1] do_syscall_64+0xf3/0x1b0 [ 43.361044][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xb3 [ 43.368744][ C1] INITIAL USE at: [ 43.372703][ C1] lock_acquire+0x169/0x480 [ 43.378929][ C1] _raw_spin_lock_irqsave+0x9e/0xc0 [ 43.385835][ C1] __wake_up+0xb8/0x150 [ 43.391786][ C1] do_notify_parent+0x167/0xce0 [ 43.398359][ C1] do_exit+0x12c5/0x1f80 [ 43.404342][ C1] call_usermodehelper_exec_async+0x47c/0x480 [ 43.412120][ C1] ret_from_fork+0x24/0x30 [ 43.418239][ C1] } [ 43.420813][ C1] ... key at: [] alloc_pid.__key+0x0/0x10 [ 43.428680][ C1] ... acquired at: [ 43.432550][ C1] lock_acquire+0x169/0x480 [ 43.437209][ C1] _raw_spin_lock+0x2a/0x40 [ 43.441858][ C1] io_submit_one+0x10f5/0x1a80 [ 43.446810][ C1] __se_sys_io_submit+0x117/0x220 [ 43.451991][ C1] do_syscall_64+0xf3/0x1b0 [ 43.456659][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xb3 [ 43.462716][ C1] [ 43.465022][ C1] -> (&ctx->ctx_lock){..-.}-{2:2} { [ 43.470203][ C1] IN-SOFTIRQ-W at: [ 43.476075][ C1] lock_acquire+0x169/0x480 [ 43.482219][ C1] _raw_spin_lock_irq+0x67/0x80 [ 43.488777][ C1] free_ioctx_users+0x30/0x1c0 [ 43.495163][ C1] percpu_ref_put+0x18d/0x1a0 [ 43.501480][ C1] rcu_core+0x816/0x1120 [ 43.507342][ C1] __do_softirq+0x268/0x80c [ 43.513476][ C1] irq_exit+0x223/0x230 [ 43.519251][ C1] smp_apic_timer_interrupt+0x113/0x280 [ 43.526448][ C1] apic_timer_interrupt+0xf/0x20 [ 43.533017][ C1] native_safe_halt+0xe/0x10 [ 43.539343][ C1] default_idle+0x4c/0x70 [ 43.546202][ C1] do_idle+0x1ee/0x650 [ 43.551907][ C1] cpu_startup_entry+0x15/0x20 [ 43.558816][ C1] start_secondary+0x386/0x410 [ 43.565204][ C1] secondary_startup_64+0xa4/0xb0 [ 43.571850][ C1] INITIAL USE at: [ 43.575721][ C1] lock_acquire+0x169/0x480 [ 43.581759][ C1] _raw_spin_lock_irq+0x67/0x80 [ 43.588155][ C1] io_submit_one+0x10cb/0x1a80 [ 43.594638][ C1] __se_sys_io_submit+0x117/0x220 [ 43.601264][ C1] do_syscall_64+0xf3/0x1b0 [ 43.607321][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xb3 [ 43.614755][ C1] } [ 43.617252][ C1] ... key at: [] ioctx_alloc.__key+0x0/0x10 [ 43.625207][ C1] ... acquired at: [ 43.628987][ C1] mark_lock+0x529/0x1b00 [ 43.633464][ C1] __lock_acquire+0xaa7/0x2b90 [ 43.638402][ C1] lock_acquire+0x169/0x480 [ 43.643080][ C1] _raw_spin_lock_irq+0x67/0x80 [ 43.648074][ C1] free_ioctx_users+0x30/0x1c0 [ 43.652983][ C1] percpu_ref_put+0x18d/0x1a0 [ 43.657803][ C1] rcu_core+0x816/0x1120 [ 43.662204][ C1] __do_softirq+0x268/0x80c [ 43.666852][ C1] irq_exit+0x223/0x230 [ 43.671151][ C1] smp_apic_timer_interrupt+0x113/0x280 [ 43.676843][ C1] apic_timer_interrupt+0xf/0x20 [ 43.681925][ C1] native_safe_halt+0xe/0x10 [ 43.686657][ C1] default_idle+0x4c/0x70 [ 43.691130][ C1] do_idle+0x1ee/0x650 [ 43.695345][ C1] cpu_startup_entry+0x15/0x20 [ 43.700253][ C1] start_secondary+0x386/0x410 [ 43.705163][ C1] secondary_startup_64+0xa4/0xb0 [ 43.710324][ C1] [ 43.712623][ C1] [ 43.712623][ C1] stack backtrace: [ 43.718496][ C1] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.6.0-syzkaller #0 [ 43.726020][ C1] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 43.736071][ C1] Call Trace: [ 43.739344][ C1] [ 43.742176][ C1] dump_stack+0x1e9/0x30e [ 43.746656][ C1] print_irq_inversion_bug+0xb67/0xe90 [ 43.752097][ C1] ? arch_stack_walk+0xb4/0xe0 [ 43.756836][ C1] ? secondary_startup_64+0xa4/0xb0 [ 43.762016][ C1] check_usage_forwards+0x13f/0x240 [ 43.767200][ C1] ? save_trace+0x49/0xb60 [ 43.771598][ C1] mark_lock+0x529/0x1b00 [ 43.775915][ C1] ? check_usage_backwards+0x240/0x240 [ 43.781362][ C1] ? mark_lock+0x102/0x1b00 [ 43.785841][ C1] ? __lock_acquire+0x116c/0x2b90 [ 43.790839][ C1] __lock_acquire+0xaa7/0x2b90 [ 43.795597][ C1] ? pcpu_block_update+0x564/0x890 [ 43.800693][ C1] lock_acquire+0x169/0x480 [ 43.805167][ C1] ? free_ioctx_users+0x30/0x1c0 [ 43.810075][ C1] ? rcu_lock_acquire+0x5/0x30 [ 43.814998][ C1] ? trace_irq_disable_rcuidle+0x1f/0x1d0 [ 43.820685][ C1] ? percpu_ref_noop_confirm_switch+0x10/0x10 [ 43.826761][ C1] _raw_spin_lock_irq+0x67/0x80 [ 43.831597][ C1] ? free_ioctx_users+0x30/0x1c0 [ 43.836509][ C1] free_ioctx_users+0x30/0x1c0 [ 43.841355][ C1] ? percpu_ref_noop_confirm_switch+0x10/0x10 [ 43.847400][ C1] ? percpu_ref_noop_confirm_switch+0x10/0x10 [ 43.853549][ C1] percpu_ref_put+0x18d/0x1a0 [ 43.858216][ C1] rcu_core+0x816/0x1120 [ 43.862439][ C1] __do_softirq+0x268/0x80c [ 43.866916][ C1] ? irq_exit+0x223/0x230 [ 43.871224][ C1] irq_exit+0x223/0x230 [ 43.875377][ C1] smp_apic_timer_interrupt+0x113/0x280 [ 43.880926][ C1] apic_timer_interrupt+0xf/0x20 [ 43.885841][ C1] [ 43.888759][ C1] RIP: 0010:native_safe_halt+0xe/0x10 [ 43.894122][ C1] Code: 80 e1 07 80 c1 03 38 c1 7c bc 48 89 df e8 4a 29 a7 f9 eb b2 cc cc cc cc cc cc cc cc e9 07 00 00 00 0f 00 2d 36 c3 58 00 fb f4 90 e9 07 00 00 00 0f 00 2d 26 c3 58 00 f4 c3 cc cc 41 56 53 65 [ 43.913842][ C1] RSP: 0018:ffffc90000d3fe60 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 [ 43.922228][ C1] RAX: 1ffffffff1257409 RBX: ffff8880a9a3c340 RCX: dffffc0000000000 [ 43.930184][ C1] RDX: dffffc0000000000 RSI: 0000000000000000 RDI: ffff8880a9a3cba4 [ 43.938139][ C1] RBP: ffffffff896b9ee0 R08: ffffffff8178ec90 R09: ffffed1015347869 [ 43.946101][ C1] R10: ffffed1015347869 R11: 0000000000000000 R12: 1ffff11015347868 [ 43.954047][ C1] R13: dffffc0000000000 R14: 1ffffffff1257407 R15: 0000000000000001 [ 43.962002][ C1] ? trace_hardirqs_on+0x30/0x70 [ 43.966915][ C1] default_idle+0x4c/0x70 [ 43.971223][ C1] do_idle+0x1ee/0x650 [ 43.975266][ C1] cpu_startup_entry+0x15/0x20 [ 43.981008][ C1] start_secondary+0x386/0x410 [ 43.985750][ C1] secondary_startup_64+0xa4/0xb0