[ 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 '10.128.0.174' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 56.573980][ C1] [ 56.576336][ C1] ======================================================== [ 56.583500][ C1] WARNING: possible irq lock inversion dependency detected [ 56.590667][ C1] 5.6.0-syzkaller #0 Not tainted [ 56.595607][ C1] -------------------------------------------------------- [ 56.602771][ C1] swapper/1/0 just changed the state of lock: [ 56.608854][ C1] ffff888094815cd8 (&ctx->ctx_lock){..-.}-{2:2}, at: free_ioctx_users+0x2b/0x450 [ 56.617949][ C1] but this lock took another, SOFTIRQ-unsafe lock in the past: [ 56.625458][ C1] (&pid->wait_pidfd){+.+.}-{2:2} [ 56.625465][ C1] [ 56.625465][ C1] [ 56.625465][ C1] and interrupts could create inverse lock ordering between them. [ 56.625465][ C1] [ 56.644738][ C1] [ 56.644738][ C1] other info that might help us debug this: [ 56.652788][ C1] Possible interrupt unsafe locking scenario: [ 56.652788][ C1] [ 56.661080][ C1] CPU0 CPU1 [ 56.666436][ C1] ---- ---- [ 56.671774][ C1] lock(&pid->wait_pidfd); [ 56.676247][ C1] local_irq_disable(); [ 56.682973][ C1] lock(&ctx->ctx_lock); [ 56.689789][ C1] lock(&pid->wait_pidfd); [ 56.696779][ C1] [ 56.700207][ C1] lock(&ctx->ctx_lock); [ 56.704694][ C1] [ 56.704694][ C1] *** DEADLOCK *** [ 56.704694][ C1] [ 56.712813][ C1] 2 locks held by swapper/1/0: [ 56.717567][ C1] #0: ffffffff899bbaa0 (rcu_callback){....}-{0:0}, at: rcu_core+0x520/0x1370 [ 56.726397][ C1] #1: ffffffff899bbbc0 (rcu_read_lock){....}-{1:2}, at: percpu_ref_switch_to_atomic_rcu+0x209/0x540 [ 56.737284][ C1] [ 56.737284][ C1] the shortest dependencies between 2nd lock and 1st lock: [ 56.746643][ C1] -> (&pid->wait_pidfd){+.+.}-{2:2} { [ 56.752086][ C1] HARDIRQ-ON-W at: [ 56.756185][ C1] lock_acquire+0x1f2/0x8f0 [ 56.762507][ C1] _raw_spin_lock+0x2a/0x40 [ 56.768833][ C1] proc_pid_make_inode+0x1f9/0x3c0 [ 56.775758][ C1] proc_pid_instantiate+0x51/0x150 [ 56.782679][ C1] proc_pid_lookup+0x1da/0x340 [ 56.789246][ C1] proc_root_lookup+0x20/0x60 [ 56.795733][ C1] __lookup_slow+0x256/0x490 [ 56.802130][ C1] walk_component+0x418/0x6a0 [ 56.808611][ C1] link_path_walk.part.0+0x4f1/0xb50 [ 56.815710][ C1] path_openat+0x25a/0x27d0 [ 56.822160][ C1] do_filp_open+0x192/0x260 [ 56.828471][ C1] do_sys_openat2+0x585/0x7d0 [ 56.834959][ C1] do_sys_open+0xc3/0x140 [ 56.841117][ C1] do_syscall_64+0xf6/0x7d0 [ 56.847428][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xb3 [ 56.855119][ C1] SOFTIRQ-ON-W at: [ 56.859169][ C1] lock_acquire+0x1f2/0x8f0 [ 56.865477][ C1] _raw_spin_lock+0x2a/0x40 [ 56.871787][ C1] proc_pid_make_inode+0x1f9/0x3c0 [ 56.878701][ C1] proc_pid_instantiate+0x51/0x150 [ 56.885624][ C1] proc_pid_lookup+0x1da/0x340 [ 56.892184][ C1] proc_root_lookup+0x20/0x60 [ 56.898658][ C1] __lookup_slow+0x256/0x490 [ 56.905058][ C1] walk_component+0x418/0x6a0 [ 56.911531][ C1] link_path_walk.part.0+0x4f1/0xb50 [ 56.918624][ C1] path_openat+0x25a/0x27d0 [ 56.924934][ C1] do_filp_open+0x192/0x260 [ 56.931240][ C1] do_sys_openat2+0x585/0x7d0 [ 56.937716][ C1] do_sys_open+0xc3/0x140 [ 56.943850][ C1] do_syscall_64+0xf6/0x7d0 [ 56.950166][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xb3 [ 56.957852][ C1] INITIAL USE at: [ 56.961844][ C1] lock_acquire+0x1f2/0x8f0 [ 56.968063][ C1] _raw_spin_lock_irqsave+0x8c/0xbf [ 56.974975][ C1] __wake_up_common_lock+0xb4/0x130 [ 56.981884][ C1] do_notify_parent+0x19e/0xe60 [ 56.988456][ C1] do_exit+0x238f/0x2dd0 [ 56.994425][ C1] call_usermodehelper_exec_async+0x507/0x710 [ 57.002226][ C1] ret_from_fork+0x24/0x30 [ 57.008364][ C1] } [ 57.010962][ C1] ... key at: [] __key.53786+0x0/0x40 [ 57.018475][ C1] ... acquired at: [ 57.022351][ C1] _raw_spin_lock+0x2a/0x40 [ 57.027020][ C1] io_submit_one+0xc1b/0x2ec0 [ 57.032540][ C1] __ia32_compat_sys_io_submit+0x1bf/0x530 [ 57.038496][ C1] do_fast_syscall_32+0x270/0xe90 [ 57.043679][ C1] entry_SYSENTER_compat+0x70/0x7f [ 57.049022][ C1] [ 57.051335][ C1] -> (&ctx->ctx_lock){..-.}-{2:2} { [ 57.056512][ C1] IN-SOFTIRQ-W at: [ 57.060472][ C1] lock_acquire+0x1f2/0x8f0 [ 57.066599][ C1] _raw_spin_lock_irq+0x5b/0x80 [ 57.073105][ C1] free_ioctx_users+0x2b/0x450 [ 57.079599][ C1] percpu_ref_switch_to_atomic_rcu+0x494/0x540 [ 57.087376][ C1] rcu_core+0x59f/0x1370 [ 57.093256][ C1] __do_softirq+0x26c/0x9f7 [ 57.099387][ C1] irq_exit+0x192/0x1d0 [ 57.105184][ C1] smp_apic_timer_interrupt+0x19e/0x600 [ 57.112354][ C1] apic_timer_interrupt+0xf/0x20 [ 57.118915][ C1] native_safe_halt+0xe/0x10 [ 57.125129][ C1] default_idle+0x49/0x350 [ 57.131168][ C1] do_idle+0x393/0x690 [ 57.136863][ C1] cpu_startup_entry+0x14/0x20 [ 57.143251][ C1] start_secondary+0x2f3/0x400 [ 57.149641][ C1] secondary_startup_64+0xa4/0xb0 [ 57.156286][ C1] INITIAL USE at: [ 57.160160][ C1] lock_acquire+0x1f2/0x8f0 [ 57.166202][ C1] _raw_spin_lock_irq+0x5b/0x80 [ 57.172589][ C1] io_submit_one+0xbd6/0x2ec0 [ 57.178861][ C1] __ia32_compat_sys_io_submit+0x1bf/0x530 [ 57.186207][ C1] do_fast_syscall_32+0x270/0xe90 [ 57.192768][ C1] entry_SYSENTER_compat+0x70/0x7f [ 57.199407][ C1] } [ 57.201892][ C1] ... key at: [] __key.55262+0x0/0x40 [ 57.209316][ C1] ... acquired at: [ 57.213098][ C1] mark_lock+0x624/0xf10 [ 57.217488][ C1] __lock_acquire+0x1d28/0x4e00 [ 57.222496][ C1] lock_acquire+0x1f2/0x8f0 [ 57.227160][ C1] _raw_spin_lock_irq+0x5b/0x80 [ 57.232158][ C1] free_ioctx_users+0x2b/0x450 [ 57.237072][ C1] percpu_ref_switch_to_atomic_rcu+0x494/0x540 [ 57.243386][ C1] rcu_core+0x59f/0x1370 [ 57.247775][ C1] __do_softirq+0x26c/0x9f7 [ 57.252424][ C1] irq_exit+0x192/0x1d0 [ 57.256726][ C1] smp_apic_timer_interrupt+0x19e/0x600 [ 57.262421][ C1] apic_timer_interrupt+0xf/0x20 [ 57.267519][ C1] native_safe_halt+0xe/0x10 [ 57.272256][ C1] default_idle+0x49/0x350 [ 57.276834][ C1] do_idle+0x393/0x690 [ 57.281060][ C1] cpu_startup_entry+0x14/0x20 [ 57.285973][ C1] start_secondary+0x2f3/0x400 [ 57.290895][ C1] secondary_startup_64+0xa4/0xb0 [ 57.296058][ C1] [ 57.298359][ C1] [ 57.298359][ C1] stack backtrace: [ 57.304239][ C1] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.6.0-syzkaller #0 [ 57.311750][ C1] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 57.321777][ C1] Call Trace: [ 57.325037][ C1] [ 57.327885][ C1] dump_stack+0x188/0x20d [ 57.332193][ C1] check_usage_forwards.cold+0x20/0x29 [ 57.337626][ C1] ? check_usage_backwards+0x4e0/0x4e0 [ 57.343059][ C1] ? stack_trace_consume_entry+0x160/0x160 [ 57.348883][ C1] ? update_group_capacity+0x7b0/0x7b0 [ 57.354332][ C1] ? save_trace+0x42/0x9f0 [ 57.358732][ C1] mark_lock+0x624/0xf10 [ 57.362950][ C1] ? check_usage_backwards+0x4e0/0x4e0 [ 57.368382][ C1] ? print_usage_bug+0x240/0x240 [ 57.373295][ C1] ? print_usage_bug+0x240/0x240 [ 57.378208][ C1] ? mark_lock+0x12b/0xf10 [ 57.382598][ C1] __lock_acquire+0x1d28/0x4e00 [ 57.387428][ C1] ? mark_held_locks+0xe0/0xe0 [ 57.392200][ C1] ? __wake_up_common_lock+0xde/0x130 [ 57.397555][ C1] lock_acquire+0x1f2/0x8f0 [ 57.402038][ C1] ? free_ioctx_users+0x2b/0x450 [ 57.406974][ C1] ? lock_release+0x800/0x800 [ 57.411638][ C1] ? lock_acquire+0x1f2/0x8f0 [ 57.416292][ C1] ? percpu_ref_switch_to_atomic_rcu+0x209/0x540 [ 57.422590][ C1] ? lock_release+0x800/0x800 [ 57.427245][ C1] ? _raw_spin_unlock_irqrestore+0x62/0xe0 [ 57.433025][ C1] _raw_spin_lock_irq+0x5b/0x80 [ 57.437852][ C1] ? free_ioctx_users+0x2b/0x450 [ 57.442777][ C1] free_ioctx_users+0x2b/0x450 [ 57.447535][ C1] percpu_ref_switch_to_atomic_rcu+0x494/0x540 [ 57.453661][ C1] rcu_core+0x59f/0x1370 [ 57.457879][ C1] ? __rcu_read_unlock+0x700/0x700 [ 57.462964][ C1] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 57.469111][ C1] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 57.475073][ C1] ? run_rebalance_domains+0x202/0x2c0 [ 57.480513][ C1] __do_softirq+0x26c/0x9f7 [ 57.485005][ C1] irq_exit+0x192/0x1d0 [ 57.489137][ C1] smp_apic_timer_interrupt+0x19e/0x600 [ 57.494660][ C1] apic_timer_interrupt+0xf/0x20 [ 57.499584][ C1] [ 57.502500][ C1] RIP: 0010:native_safe_halt+0xe/0x10 [ 57.507867][ C1] Code: cc cc cc cc cc cc cc cc cc cc cc cc e9 07 00 00 00 0f 00 2d a4 4d 5a 00 f4 c3 66 90 e9 07 00 00 00 0f 00 2d 94 4d 5a 00 fb f4 cc 41 56 41 55 41 54 55 53 e8 e3 d1 92 f9 e8 2e 9f ca fb 0f 1f [ 57.527449][ C1] RSP: 0018:ffffc90000d3fdb8 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 [ 57.535838][ C1] RAX: 1ffffffff132925f RBX: ffff8880a95f2340 RCX: 0000000000000000 [ 57.543789][ C1] RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffff8880a95f2c04 [ 57.551774][ C1] RBP: dffffc0000000000 R08: ffff8880a95f2340 R09: 0000000000000000 [ 57.559723][ C1] R10: 0000000000000000 R11: 0000000000000000 R12: ffffed10152be468 [ 57.567687][ C1] R13: 0000000000000001 R14: ffffffff8a88df40 R15: 0000000000000000 [ 57.575648][ C1] default_idle+0x49/0x350 [ 57.580042][ C1] do_idle+0x393/0x690 [ 57.584089][ C1] ? arch_cpu_idle_exit+0x70/0x70 [ 57.589091][ C1] ? _raw_spin_unlock_irqrestore+0x62/0xe0 [ 57.594871][ C1] ? lockdep_hardirqs_on+0x463/0x620 [ 57.600143][ C1] cpu_startup_entry+0x14/0x20 [ 57.604891][ C1] start_secondary+0x2f3/0x400 [ 57.609634][ C1] ? set_cpu_sibling_map+0x1ed0/0x1ed0 [ 57.615093][ C1] secondary_startup_64+0xa4/0xb0