[ OK ] Reached target Multi-User System. [ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... [ OK ] Started Load/Save RF Kill Switch Status. [ OK ] Started Update UTMP about System Runlevel Changes. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.0.15' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 61.356640][ C1] [ 61.359131][ C1] ======================================================== [ 61.366311][ C1] WARNING: possible irq lock inversion dependency detected [ 61.373493][ C1] 5.6.0-syzkaller #0 Not tainted [ 61.378597][ C1] -------------------------------------------------------- [ 61.385762][ C1] swapper/1/0 just changed the state of lock: [ 61.391800][ C1] ffff8880934c1cd8 (&ctx->ctx_lock){..-.}-{2:2}, at: free_ioctx_users+0x2b/0x450 [ 61.400905][ C1] but this lock took another, SOFTIRQ-unsafe lock in the past: [ 61.408431][ C1] (&pid->wait_pidfd){+.+.}-{2:2} [ 61.408439][ C1] [ 61.408439][ C1] [ 61.408439][ C1] and interrupts could create inverse lock ordering between them. [ 61.408439][ C1] [ 61.427787][ C1] [ 61.427787][ C1] other info that might help us debug this: [ 61.435838][ C1] Possible interrupt unsafe locking scenario: [ 61.435838][ C1] [ 61.444213][ C1] CPU0 CPU1 [ 61.449561][ C1] ---- ---- [ 61.454911][ C1] lock(&pid->wait_pidfd); [ 61.459387][ C1] local_irq_disable(); [ 61.466139][ C1] lock(&ctx->ctx_lock); [ 61.472956][ C1] lock(&pid->wait_pidfd); [ 61.479947][ C1] [ 61.483376][ C1] lock(&ctx->ctx_lock); [ 61.487861][ C1] [ 61.487861][ C1] *** DEADLOCK *** [ 61.487861][ C1] [ 61.497544][ C1] 2 locks held by swapper/1/0: [ 61.502282][ C1] #0: ffffffff899bbaa0 (rcu_callback){....}-{0:0}, at: rcu_core+0x520/0x1370 [ 61.511203][ C1] #1: ffffffff899bbbc0 (rcu_read_lock){....}-{1:2}, at: percpu_ref_switch_to_atomic_rcu+0x209/0x540 [ 61.522152][ C1] [ 61.522152][ C1] the shortest dependencies between 2nd lock and 1st lock: [ 61.531516][ C1] -> (&pid->wait_pidfd){+.+.}-{2:2} { [ 61.536963][ C1] HARDIRQ-ON-W at: [ 61.541028][ C1] lock_acquire+0x1f2/0x8f0 [ 61.547332][ C1] _raw_spin_lock+0x2a/0x40 [ 61.553635][ C1] proc_pid_make_inode+0x1f9/0x3c0 [ 61.560543][ C1] proc_pid_instantiate+0x51/0x150 [ 61.567482][ C1] proc_pid_lookup+0x1da/0x340 [ 61.574181][ C1] proc_root_lookup+0x20/0x60 [ 61.580810][ C1] __lookup_slow+0x256/0x490 [ 61.587208][ C1] walk_component+0x418/0x6a0 [ 61.593837][ C1] link_path_walk.part.0+0x4f1/0xb50 [ 61.600929][ C1] path_openat+0x25a/0x27d0 [ 61.607295][ C1] do_filp_open+0x192/0x260 [ 61.613701][ C1] do_sys_openat2+0x585/0x7d0 [ 61.620233][ C1] do_sys_open+0xc3/0x140 [ 61.626482][ C1] do_syscall_64+0xf6/0x7d0 [ 61.632817][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xb3 [ 61.640570][ C1] SOFTIRQ-ON-W at: [ 61.644628][ C1] lock_acquire+0x1f2/0x8f0 [ 61.650948][ C1] _raw_spin_lock+0x2a/0x40 [ 61.657328][ C1] proc_pid_make_inode+0x1f9/0x3c0 [ 61.664251][ C1] proc_pid_instantiate+0x51/0x150 [ 61.671165][ C1] proc_pid_lookup+0x1da/0x340 [ 61.677729][ C1] proc_root_lookup+0x20/0x60 [ 61.684664][ C1] __lookup_slow+0x256/0x490 [ 61.691078][ C1] walk_component+0x418/0x6a0 [ 61.697582][ C1] link_path_walk.part.0+0x4f1/0xb50 [ 61.704667][ C1] path_openat+0x25a/0x27d0 [ 61.710970][ C1] do_filp_open+0x192/0x260 [ 61.717273][ C1] do_sys_openat2+0x585/0x7d0 [ 61.723745][ C1] do_sys_open+0xc3/0x140 [ 61.729901][ C1] do_syscall_64+0xf6/0x7d0 [ 61.736205][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xb3 [ 61.743891][ C1] INITIAL USE at: [ 61.747852][ C1] lock_acquire+0x1f2/0x8f0 [ 61.754068][ C1] _raw_spin_lock_irqsave+0x8c/0xbf [ 61.760984][ C1] __wake_up_common_lock+0xb4/0x130 [ 61.767910][ C1] do_notify_parent+0x19e/0xe60 [ 61.774627][ C1] do_exit+0x238f/0x2dd0 [ 61.783192][ C1] call_usermodehelper_exec_async+0x507/0x710 [ 61.790983][ C1] ret_from_fork+0x24/0x30 [ 61.798081][ C1] } [ 61.800657][ C1] ... key at: [] __key.53827+0x0/0x40 [ 61.808186][ C1] ... acquired at: [ 61.812166][ C1] _raw_spin_lock+0x2a/0x40 [ 61.816844][ C1] io_submit_one+0xc1b/0x2ec0 [ 61.821681][ C1] __x64_sys_io_submit+0x1bd/0x540 [ 61.827082][ C1] do_syscall_64+0xf6/0x7d0 [ 61.831745][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xb3 [ 61.837797][ C1] [ 61.840107][ C1] -> (&ctx->ctx_lock){..-.}-{2:2} { [ 61.845280][ C1] IN-SOFTIRQ-W at: [ 61.849252][ C1] lock_acquire+0x1f2/0x8f0 [ 61.855403][ C1] _raw_spin_lock_irq+0x5b/0x80 [ 61.861890][ C1] free_ioctx_users+0x2b/0x450 [ 61.868296][ C1] percpu_ref_switch_to_atomic_rcu+0x494/0x540 [ 61.876094][ C1] rcu_core+0x59f/0x1370 [ 61.881983][ C1] __do_softirq+0x26c/0x9f7 [ 61.888109][ C1] irq_exit+0x192/0x1d0 [ 61.893890][ C1] smp_apic_timer_interrupt+0x19e/0x600 [ 61.901069][ C1] apic_timer_interrupt+0xf/0x20 [ 61.907631][ C1] native_safe_halt+0xe/0x10 [ 61.913855][ C1] default_idle+0x49/0x350 [ 61.919907][ C1] do_idle+0x393/0x690 [ 61.925596][ C1] cpu_startup_entry+0x14/0x20 [ 61.931986][ C1] start_secondary+0x2f3/0x400 [ 61.938373][ C1] secondary_startup_64+0xa4/0xb0 [ 61.945016][ C1] INITIAL USE at: [ 61.948902][ C1] lock_acquire+0x1f2/0x8f0 [ 61.954958][ C1] _raw_spin_lock_irq+0x5b/0x80 [ 61.961365][ C1] io_submit_one+0xbd6/0x2ec0 [ 61.967594][ C1] __x64_sys_io_submit+0x1bd/0x540 [ 61.974346][ C1] do_syscall_64+0xf6/0x7d0 [ 61.980397][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xb3 [ 61.987884][ C1] } [ 61.990483][ C1] ... key at: [] __key.55303+0x0/0x40 [ 61.998094][ C1] ... acquired at: [ 62.002124][ C1] mark_lock+0x624/0xf10 [ 62.006521][ C1] __lock_acquire+0x1d28/0x4e00 [ 62.011522][ C1] lock_acquire+0x1f2/0x8f0 [ 62.016178][ C1] _raw_spin_lock_irq+0x5b/0x80 [ 62.021179][ C1] free_ioctx_users+0x2b/0x450 [ 62.026113][ C1] percpu_ref_switch_to_atomic_rcu+0x494/0x540 [ 62.032536][ C1] rcu_core+0x59f/0x1370 [ 62.036933][ C1] __do_softirq+0x26c/0x9f7 [ 62.041594][ C1] irq_exit+0x192/0x1d0 [ 62.045898][ C1] smp_apic_timer_interrupt+0x19e/0x600 [ 62.051589][ C1] apic_timer_interrupt+0xf/0x20 [ 62.056734][ C1] native_safe_halt+0xe/0x10 [ 62.061506][ C1] default_idle+0x49/0x350 [ 62.066295][ C1] do_idle+0x393/0x690 [ 62.070532][ C1] cpu_startup_entry+0x14/0x20 [ 62.075455][ C1] start_secondary+0x2f3/0x400 [ 62.080475][ C1] secondary_startup_64+0xa4/0xb0 [ 62.085757][ C1] [ 62.088062][ C1] [ 62.088062][ C1] stack backtrace: [ 62.093960][ C1] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.6.0-syzkaller #0 [ 62.101631][ C1] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 62.111670][ C1] Call Trace: [ 62.114946][ C1] [ 62.117784][ C1] dump_stack+0x188/0x20d [ 62.122101][ C1] check_usage_forwards.cold+0x20/0x29 [ 62.127566][ C1] ? check_usage_backwards+0x4e0/0x4e0 [ 62.133002][ C1] ? stack_trace_consume_entry+0x160/0x160 [ 62.139394][ C1] ? __read_once_size_nocheck.constprop.0+0x10/0x10 [ 62.145957][ C1] ? get_stack_info+0x32/0x13e [ 62.150737][ C1] ? save_trace+0x42/0x9f0 [ 62.155129][ C1] mark_lock+0x624/0xf10 [ 62.159347][ C1] ? check_usage_backwards+0x4e0/0x4e0 [ 62.164953][ C1] ? print_usage_bug+0x240/0x240 [ 62.169867][ C1] ? print_usage_bug+0x240/0x240 [ 62.174790][ C1] ? mark_lock+0x12b/0xf10 [ 62.179191][ C1] __lock_acquire+0x1d28/0x4e00 [ 62.184029][ C1] ? mark_held_locks+0xe0/0xe0 [ 62.188788][ C1] ? __wake_up_common_lock+0xde/0x130 [ 62.194144][ C1] lock_acquire+0x1f2/0x8f0 [ 62.198637][ C1] ? free_ioctx_users+0x2b/0x450 [ 62.203549][ C1] ? lock_release+0x800/0x800 [ 62.208219][ C1] ? lock_acquire+0x1f2/0x8f0 [ 62.212956][ C1] ? percpu_ref_switch_to_atomic_rcu+0x209/0x540 [ 62.219256][ C1] ? lock_release+0x800/0x800 [ 62.223908][ C1] ? _raw_spin_unlock_irqrestore+0x62/0xe0 [ 62.229702][ C1] _raw_spin_lock_irq+0x5b/0x80 [ 62.234533][ C1] ? free_ioctx_users+0x2b/0x450 [ 62.239536][ C1] free_ioctx_users+0x2b/0x450 [ 62.244299][ C1] percpu_ref_switch_to_atomic_rcu+0x494/0x540 [ 62.250518][ C1] rcu_core+0x59f/0x1370 [ 62.254735][ C1] ? __rcu_read_unlock+0x700/0x700 [ 62.259819][ C1] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 62.265772][ C1] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 62.271739][ C1] ? run_rebalance_domains+0x202/0x2c0 [ 62.277189][ C1] __do_softirq+0x26c/0x9f7 [ 62.281685][ C1] irq_exit+0x192/0x1d0 [ 62.285833][ C1] smp_apic_timer_interrupt+0x19e/0x600 [ 62.291359][ C1] apic_timer_interrupt+0xf/0x20 [ 62.296357][ C1] [ 62.299277][ C1] RIP: 0010:native_safe_halt+0xe/0x10 [ 62.304977][ C1] Code: cc cc cc cc cc cc cc cc cc cc cc cc e9 07 00 00 00 0f 00 2d d4 f2 59 00 f4 c3 66 90 e9 07 00 00 00 0f 00 2d c4 f2 59 00 fb f4 cc 41 56 41 55 41 54 55 53 e8 33 77 92 f9 e8 fe b2 ca fb 0f 1f [ 62.325023][ C1] RSP: 0018:ffffc90000d3fdb8 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13 [ 62.333417][ C1] RAX: 1ffffffff132925f RBX: ffff8880a95f2340 RCX: 0000000000000000 [ 62.341387][ C1] RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffff8880a95f2c04 [ 62.349359][ C1] RBP: dffffc0000000000 R08: ffff8880a95f2340 R09: 0000000000000000 [ 62.357324][ C1] R10: 0000000000000000 R11: 0000000000000000 R12: ffffed10152be468 [ 62.365271][ C1] R13: 0000000000000001 R14: ffffffff8a88e980 R15: 0000000000000000 [ 62.373379][ C1] default_idle+0x49/0x350 [ 62.377788][ C1] do_idle+0x393/0x690 [ 62.381838][ C1] ? arch_cpu_idle_exit+0x70/0x70 [ 62.387084][ C1] ? _raw_spin_unlock_irqrestore+0x62/0xe0 [ 62.393055][ C1] ? lockdep_hardirqs_on+0x463/0x620 [ 62.398327][ C1] cpu_startup_entry+0x14/0x20 [ 62.403090][ C1] start_secondary+0x2f3/0x400 [ 62.407839][ C1] ? set_cpu_sibling_map+0x1ed0/0x1ed0 [ 62.413281][ C1] secondary_startup_64+0xa4/0xb0