[ 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 '10.128.0.246' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 61.081276][ C1] [ 61.083650][ C1] ======================================================== [ 61.090818][ C1] WARNING: possible irq lock inversion dependency detected [ 61.098115][ C1] 5.6.0-syzkaller #0 Not tainted [ 61.103037][ C1] -------------------------------------------------------- [ 61.110223][ C1] swapper/1/0 just changed the state of lock: [ 61.116281][ C1] ffff8880a243bcd8 (&ctx->ctx_lock){..-.}-{2:2}, at: free_ioctx_users+0x2b/0x450 [ 61.125380][ C1] but this lock took another, SOFTIRQ-unsafe lock in the past: [ 61.132891][ C1] (&pid->wait_pidfd){+.+.}-{2:2} [ 61.132898][ C1] [ 61.132898][ C1] [ 61.132898][ C1] and interrupts could create inverse lock ordering between them. [ 61.132898][ C1] [ 61.152314][ C1] [ 61.152314][ C1] other info that might help us debug this: [ 61.160697][ C1] Possible interrupt unsafe locking scenario: [ 61.160697][ C1] [ 61.169021][ C1] CPU0 CPU1 [ 61.174370][ C1] ---- ---- [ 61.179785][ C1] lock(&pid->wait_pidfd); [ 61.184534][ C1] local_irq_disable(); [ 61.191287][ C1] lock(&ctx->ctx_lock); [ 61.198154][ C1] lock(&pid->wait_pidfd); [ 61.205173][ C1] [ 61.208608][ C1] lock(&ctx->ctx_lock); [ 61.213087][ C1] [ 61.213087][ C1] *** DEADLOCK *** [ 61.213087][ C1] [ 61.221225][ C1] 2 locks held by swapper/1/0: [ 61.225961][ C1] #0: ffffffff899bc060 (rcu_callback){....}-{0:0}, at: rcu_core+0x520/0x1370 [ 61.234796][ C1] #1: ffffffff899bc180 (rcu_read_lock){....}-{1:2}, at: percpu_ref_switch_to_atomic_rcu+0x209/0x540 [ 61.245627][ C1] [ 61.245627][ C1] the shortest dependencies between 2nd lock and 1st lock: [ 61.254991][ C1] -> (&pid->wait_pidfd){+.+.}-{2:2} { [ 61.260428][ C1] HARDIRQ-ON-W at: [ 61.264493][ C1] lock_acquire+0x1f2/0x8f0 [ 61.270798][ C1] _raw_spin_lock+0x2a/0x40 [ 61.277141][ C1] proc_pid_make_inode+0x1f9/0x3c0 [ 61.284071][ C1] proc_pid_instantiate+0x51/0x150 [ 61.290999][ C1] proc_pid_lookup+0x1da/0x340 [ 61.297670][ C1] proc_root_lookup+0x20/0x60 [ 61.304197][ C1] __lookup_slow+0x256/0x490 [ 61.310597][ C1] walk_component+0x418/0x6a0 [ 61.317188][ C1] link_path_walk.part.0+0x4f1/0xb50 [ 61.324284][ C1] path_openat+0x25a/0x27d0 [ 61.330646][ C1] do_filp_open+0x192/0x260 [ 61.337071][ C1] do_sys_openat2+0x585/0x7d0 [ 61.343569][ C1] do_sys_open+0xc3/0x140 [ 61.349714][ C1] do_syscall_64+0xf6/0x7d0 [ 61.356025][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xb3 [ 61.363712][ C1] SOFTIRQ-ON-W at: [ 61.367785][ C1] lock_acquire+0x1f2/0x8f0 [ 61.374086][ C1] _raw_spin_lock+0x2a/0x40 [ 61.380388][ C1] proc_pid_make_inode+0x1f9/0x3c0 [ 61.387294][ C1] proc_pid_instantiate+0x51/0x150 [ 61.394216][ C1] proc_pid_lookup+0x1da/0x340 [ 61.400778][ C1] proc_root_lookup+0x20/0x60 [ 61.407268][ C1] __lookup_slow+0x256/0x490 [ 61.413759][ C1] walk_component+0x418/0x6a0 [ 61.420263][ C1] link_path_walk.part.0+0x4f1/0xb50 [ 61.427368][ C1] path_openat+0x25a/0x27d0 [ 61.433694][ C1] do_filp_open+0x192/0x260 [ 61.440025][ C1] do_sys_openat2+0x585/0x7d0 [ 61.446592][ C1] do_sys_open+0xc3/0x140 [ 61.452938][ C1] do_syscall_64+0xf6/0x7d0 [ 61.459822][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xb3 [ 61.467534][ C1] INITIAL USE at: [ 61.471518][ C1] lock_acquire+0x1f2/0x8f0 [ 61.477758][ C1] _raw_spin_lock_irqsave+0x8c/0xbf [ 61.484784][ C1] __wake_up_common_lock+0xb4/0x130 [ 61.491718][ C1] do_notify_parent+0x19e/0xe60 [ 61.498361][ C1] do_exit+0x238f/0x2dd0 [ 61.504454][ C1] call_usermodehelper_exec_async+0x507/0x710 [ 61.512251][ C1] ret_from_fork+0x24/0x30 [ 61.518376][ C1] } [ 61.520949][ C1] ... key at: [] __key.53831+0x0/0x40 [ 61.528623][ C1] ... acquired at: [ 61.532606][ C1] _raw_spin_lock+0x2a/0x40 [ 61.537266][ C1] io_submit_one+0xc1b/0x2ec0 [ 61.542098][ C1] __x64_sys_io_submit+0x1bd/0x540 [ 61.547491][ C1] do_syscall_64+0xf6/0x7d0 [ 61.552329][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xb3 [ 61.558378][ C1] [ 61.560715][ C1] -> (&ctx->ctx_lock){..-.}-{2:2} { [ 61.565923][ C1] IN-SOFTIRQ-W at: [ 61.570391][ C1] lock_acquire+0x1f2/0x8f0 [ 61.576549][ C1] _raw_spin_lock_irq+0x5b/0x80 [ 61.583064][ C1] free_ioctx_users+0x2b/0x450 [ 61.589475][ C1] percpu_ref_switch_to_atomic_rcu+0x494/0x540 [ 61.597386][ C1] rcu_core+0x59f/0x1370 [ 61.603283][ C1] __do_softirq+0x26c/0x9f7 [ 61.609506][ C1] irq_exit+0x192/0x1d0 [ 61.615304][ C1] smp_apic_timer_interrupt+0x19e/0x600 [ 61.622538][ C1] apic_timer_interrupt+0xf/0x20 [ 61.629214][ C1] native_safe_halt+0xe/0x10 [ 61.635477][ C1] default_idle+0x49/0x350 [ 61.641539][ C1] do_idle+0x393/0x690 [ 61.647235][ C1] cpu_startup_entry+0x14/0x20 [ 61.653627][ C1] start_secondary+0x2f3/0x400 [ 61.660243][ C1] secondary_startup_64+0xa4/0xb0 [ 61.667078][ C1] INITIAL USE at: [ 61.670973][ C1] lock_acquire+0x1f2/0x8f0 [ 61.677094][ C1] _raw_spin_lock_irq+0x5b/0x80 [ 61.683522][ C1] io_submit_one+0xbd6/0x2ec0 [ 61.689757][ C1] __x64_sys_io_submit+0x1bd/0x540 [ 61.696414][ C1] do_syscall_64+0xf6/0x7d0 [ 61.702459][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xb3 [ 61.709883][ C1] } [ 61.712380][ C1] ... key at: [] __key.55314+0x0/0x40 [ 61.720019][ C1] ... acquired at: [ 61.723833][ C1] mark_lock+0x624/0xf10 [ 61.728307][ C1] __lock_acquire+0x1d28/0x4e00 [ 61.733404][ C1] lock_acquire+0x1f2/0x8f0 [ 61.738081][ C1] _raw_spin_lock_irq+0x5b/0x80 [ 61.743103][ C1] free_ioctx_users+0x2b/0x450 [ 61.748027][ C1] percpu_ref_switch_to_atomic_rcu+0x494/0x540 [ 61.754385][ C1] rcu_core+0x59f/0x1370 [ 61.758834][ C1] __do_softirq+0x26c/0x9f7 [ 61.763490][ C1] irq_exit+0x192/0x1d0 [ 61.767795][ C1] smp_apic_timer_interrupt+0x19e/0x600 [ 61.773501][ C1] apic_timer_interrupt+0xf/0x20 [ 61.778598][ C1] native_safe_halt+0xe/0x10 [ 61.783337][ C1] default_idle+0x49/0x350 [ 61.787914][ C1] do_idle+0x393/0x690 [ 61.792147][ C1] cpu_startup_entry+0x14/0x20 [ 61.797085][ C1] start_secondary+0x2f3/0x400 [ 61.802013][ C1] secondary_startup_64+0xa4/0xb0 [ 61.807193][ C1] [ 61.809505][ C1] [ 61.809505][ C1] stack backtrace: [ 61.815372][ C1] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.6.0-syzkaller #0 [ 61.822900][ C1] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 61.832930][ C1] Call Trace: [ 61.836207][ C1] [ 61.839136][ C1] dump_stack+0x188/0x20d [ 61.843585][ C1] check_usage_forwards.cold+0x20/0x29 [ 61.849045][ C1] ? check_usage_backwards+0x4e0/0x4e0 [ 61.854548][ C1] ? stack_trace_consume_entry+0x160/0x160 [ 61.860354][ C1] ? __read_once_size_nocheck.constprop.0+0x10/0x10 [ 61.867020][ C1] ? get_stack_info+0x32/0x13e [ 61.871796][ C1] ? save_trace+0x42/0x9f0 [ 61.876341][ C1] mark_lock+0x624/0xf10 [ 61.880641][ C1] ? check_usage_backwards+0x4e0/0x4e0 [ 61.886108][ C1] ? print_usage_bug+0x240/0x240 [ 61.891029][ C1] ? print_usage_bug+0x240/0x240 [ 61.896010][ C1] ? mark_lock+0x12b/0xf10 [ 61.900414][ C1] __lock_acquire+0x1d28/0x4e00 [ 61.905370][ C1] ? mark_held_locks+0xe0/0xe0 [ 61.910122][ C1] ? __wake_up_common_lock+0xde/0x130 [ 61.915481][ C1] lock_acquire+0x1f2/0x8f0 [ 61.919972][ C1] ? free_ioctx_users+0x2b/0x450 [ 61.924902][ C1] ? lock_release+0x800/0x800 [ 61.929553][ C1] ? lock_acquire+0x1f2/0x8f0 [ 61.934210][ C1] ? percpu_ref_switch_to_atomic_rcu+0x209/0x540 [ 61.940532][ C1] ? lock_release+0x800/0x800 [ 61.945191][ C1] ? _raw_spin_unlock_irqrestore+0x62/0xe0 [ 61.950974][ C1] _raw_spin_lock_irq+0x5b/0x80 [ 61.956012][ C1] ? free_ioctx_users+0x2b/0x450 [ 61.960949][ C1] free_ioctx_users+0x2b/0x450 [ 61.965691][ C1] percpu_ref_switch_to_atomic_rcu+0x494/0x540 [ 61.971838][ C1] rcu_core+0x59f/0x1370 [ 61.976080][ C1] ? __rcu_read_unlock+0x700/0x700 [ 61.981195][ C1] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 61.986736][ C1] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 61.992772][ C1] ? run_rebalance_domains+0x202/0x2c0 [ 61.998272][ C1] __do_softirq+0x26c/0x9f7 [ 62.002765][ C1] irq_exit+0x192/0x1d0 [ 62.006921][ C1] smp_apic_timer_interrupt+0x19e/0x600 [ 62.012450][ C1] apic_timer_interrupt+0xf/0x20 [ 62.017419][ C1] [ 62.020408][ C1] RIP: 0010:native_safe_halt+0xe/0x10 [ 62.025774][ C1] Code: cc cc cc cc cc cc cc cc cc cc cc cc e9 07 00 00 00 0f 00 2d 84 1e 59 00 f4 c3 66 90 e9 07 00 00 00 0f 00 2d 74 1e 59 00 fb f4 cc 41 56 41 55 41 54 55 53 e8 83 91 91 f9 e8 ce 2c ca fb 0f 1f [ 62.045400][ C1] RSP: 0018:ffffc90000d3fdb8 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13 [ 62.053894][ C1] RAX: 1ffffffff132930f RBX: ffff8880a95f2340 RCX: 0000000000000000 [ 62.061857][ C1] RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffff8880a95f2c04 [ 62.070335][ C1] RBP: dffffc0000000000 R08: ffff8880a95f2340 R09: 0000000000000000 [ 62.078294][ C1] R10: 0000000000000000 R11: 0000000000000000 R12: ffffed10152be468 [ 62.086247][ C1] R13: 0000000000000001 R14: ffffffff8a890cc0 R15: 0000000000000000 [ 62.094225][ C1] default_idle+0x49/0x350 [ 62.098633][ C1] do_idle+0x393/0x690 [ 62.102694][ C1] ? migrate_swap_stop+0x9d0/0x9d0 [ 62.107783][ C1] ? arch_cpu_idle_exit+0x70/0x70 [ 62.112796][ C1] ? _raw_spin_unlock_irqrestore+0x62/0xe0 [ 62.118579][ C1] ? lockdep_hardirqs_on+0x463/0x620 [ 62.123862][ C1] cpu_startup_entry+0x14/0x20 [ 62.128612][ C1] start_secondary+0x2f3/0x400 [ 62.133359][ C1] ? set_cpu_sibling_map+0x1ed0/0x1ed0 [ 62.138884][ C1] secondary_startup_64+0xa4/0xb0