Starting Load/Save RF Kill Switch Status... [ OK ] Started Load/Save RF Kill Switch Status. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.10.37' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 58.432740][ C0] [ 58.435108][ C0] ======================================================== [ 58.442318][ C0] WARNING: possible irq lock inversion dependency detected [ 58.449489][ C0] 5.6.0-syzkaller #0 Not tainted [ 58.454444][ C0] -------------------------------------------------------- [ 58.461613][ C0] swapper/0/0 just changed the state of lock: [ 58.467651][ C0] ffff8880a81edcd8 (&ctx->ctx_lock){..-.}-{2:2}, at: free_ioctx_users+0x2b/0x450 [ 58.476741][ C0] but this lock took another, SOFTIRQ-unsafe lock in the past: [ 58.484254][ C0] (&pid->wait_pidfd){+.+.}-{2:2} [ 58.484261][ C0] [ 58.484261][ C0] [ 58.484261][ C0] and interrupts could create inverse lock ordering between them. [ 58.484261][ C0] [ 58.503542][ C0] [ 58.503542][ C0] other info that might help us debug this: [ 58.511592][ C0] Possible interrupt unsafe locking scenario: [ 58.511592][ C0] [ 58.519887][ C0] CPU0 CPU1 [ 58.525276][ C0] ---- ---- [ 58.530717][ C0] lock(&pid->wait_pidfd); [ 58.535225][ C0] local_irq_disable(); [ 58.541989][ C0] lock(&ctx->ctx_lock); [ 58.548825][ C0] lock(&pid->wait_pidfd); [ 58.555820][ C0] [ 58.559257][ C0] lock(&ctx->ctx_lock); [ 58.563739][ C0] [ 58.563739][ C0] *** DEADLOCK *** [ 58.563739][ C0] [ 58.571863][ C0] 2 locks held by swapper/0/0: [ 58.576609][ C0] #0: ffffffff899baba0 (rcu_callback){....}-{0:0}, at: rcu_core+0x520/0x1370 [ 58.585491][ C0] #1: ffffffff899bacc0 (rcu_read_lock){....}-{1:2}, at: percpu_ref_switch_to_atomic_rcu+0x209/0x540 [ 58.596320][ C0] [ 58.596320][ C0] the shortest dependencies between 2nd lock and 1st lock: [ 58.605676][ C0] -> (&pid->wait_pidfd){+.+.}-{2:2} { [ 58.611122][ C0] HARDIRQ-ON-W at: [ 58.615192][ C0] lock_acquire+0x1f2/0x8f0 [ 58.621515][ C0] _raw_spin_lock+0x2a/0x40 [ 58.627848][ C0] proc_pid_make_inode+0x1f9/0x3c0 [ 58.634766][ C0] proc_pid_instantiate+0x51/0x150 [ 58.641680][ C0] proc_pid_lookup+0x1da/0x340 [ 58.648253][ C0] proc_root_lookup+0x20/0x60 [ 58.654733][ C0] __lookup_slow+0x256/0x490 [ 58.661137][ C0] walk_component+0x418/0x6a0 [ 58.667629][ C0] link_path_walk.part.0+0x4f1/0xb50 [ 58.674715][ C0] path_openat+0x25a/0x27b0 [ 58.681021][ C0] do_filp_open+0x203/0x260 [ 58.687328][ C0] do_sys_openat2+0x585/0x770 [ 58.693814][ C0] do_sys_open+0xc3/0x140 [ 58.699943][ C0] do_syscall_64+0xf6/0x7d0 [ 58.706253][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xb3 [ 58.713964][ C0] SOFTIRQ-ON-W at: [ 58.718107][ C0] lock_acquire+0x1f2/0x8f0 [ 58.724451][ C0] _raw_spin_lock+0x2a/0x40 [ 58.730756][ C0] proc_pid_make_inode+0x1f9/0x3c0 [ 58.737669][ C0] proc_pid_instantiate+0x51/0x150 [ 58.744580][ C0] proc_pid_lookup+0x1da/0x340 [ 58.751144][ C0] proc_root_lookup+0x20/0x60 [ 58.757620][ C0] __lookup_slow+0x256/0x490 [ 58.764012][ C0] walk_component+0x418/0x6a0 [ 58.770485][ C0] link_path_walk.part.0+0x4f1/0xb50 [ 58.777579][ C0] path_openat+0x25a/0x27b0 [ 58.783903][ C0] do_filp_open+0x203/0x260 [ 58.790206][ C0] do_sys_openat2+0x585/0x770 [ 58.796682][ C0] do_sys_open+0xc3/0x140 [ 58.802813][ C0] do_syscall_64+0xf6/0x7d0 [ 58.809130][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xb3 [ 58.816820][ C0] INITIAL USE at: [ 58.820797][ C0] lock_acquire+0x1f2/0x8f0 [ 58.827029][ C0] _raw_spin_lock_irqsave+0x8c/0xbf [ 58.833955][ C0] __wake_up_common_lock+0xb4/0x130 [ 58.840862][ C0] do_notify_parent+0x19e/0xe60 [ 58.847458][ C0] do_exit+0x238f/0x2dd0 [ 58.853415][ C0] call_usermodehelper_exec_async+0x507/0x710 [ 58.861194][ C0] ret_from_fork+0x24/0x30 [ 58.867318][ C0] } [ 58.869912][ C0] ... key at: [] __key.53714+0x0/0x40 [ 58.877425][ C0] ... acquired at: [ 58.881295][ C0] _raw_spin_lock+0x2a/0x40 [ 58.885948][ C0] io_submit_one+0xc1b/0x2ec0 [ 58.890777][ C0] __ia32_compat_sys_io_submit+0x1bf/0x530 [ 58.896732][ C0] do_fast_syscall_32+0x270/0xe90 [ 58.901922][ C0] entry_SYSENTER_compat+0x70/0x7f [ 58.907192][ C0] [ 58.909500][ C0] -> (&ctx->ctx_lock){..-.}-{2:2} { [ 58.914674][ C0] IN-SOFTIRQ-W at: [ 58.918639][ C0] lock_acquire+0x1f2/0x8f0 [ 58.924768][ C0] _raw_spin_lock_irq+0x5b/0x80 [ 58.931245][ C0] free_ioctx_users+0x2b/0x450 [ 58.937636][ C0] percpu_ref_switch_to_atomic_rcu+0x494/0x540 [ 58.945430][ C0] rcu_core+0x59f/0x1370 [ 58.951295][ C0] __do_softirq+0x26c/0x9f7 [ 58.957439][ C0] irq_exit+0x192/0x1d0 [ 58.963220][ C0] smp_apic_timer_interrupt+0x19e/0x600 [ 58.970392][ C0] apic_timer_interrupt+0xf/0x20 [ 58.976957][ C0] native_safe_halt+0xe/0x10 [ 58.983193][ C0] default_idle+0x49/0x350 [ 58.989235][ C0] do_idle+0x393/0x690 [ 58.994937][ C0] cpu_startup_entry+0x14/0x20 [ 59.001328][ C0] start_kernel+0x867/0x8a1 [ 59.007465][ C0] secondary_startup_64+0xa4/0xb0 [ 59.014112][ C0] INITIAL USE at: [ 59.017992][ C0] lock_acquire+0x1f2/0x8f0 [ 59.024032][ C0] _raw_spin_lock_irq+0x5b/0x80 [ 59.030421][ C0] io_submit_one+0xbd6/0x2ec0 [ 59.036653][ C0] __ia32_compat_sys_io_submit+0x1bf/0x530 [ 59.044001][ C0] do_fast_syscall_32+0x270/0xe90 [ 59.050566][ C0] entry_SYSENTER_compat+0x70/0x7f [ 59.057223][ C0] } [ 59.059714][ C0] ... key at: [] __key.55192+0x0/0x40 [ 59.067148][ C0] ... acquired at: [ 59.070940][ C0] mark_lock+0x624/0xf10 [ 59.075337][ C0] __lock_acquire+0x1d28/0x4e00 [ 59.080354][ C0] lock_acquire+0x1f2/0x8f0 [ 59.085017][ C0] _raw_spin_lock_irq+0x5b/0x80 [ 59.090015][ C0] free_ioctx_users+0x2b/0x450 [ 59.094932][ C0] percpu_ref_switch_to_atomic_rcu+0x494/0x540 [ 59.101263][ C0] rcu_core+0x59f/0x1370 [ 59.105670][ C0] __do_softirq+0x26c/0x9f7 [ 59.110342][ C0] irq_exit+0x192/0x1d0 [ 59.114649][ C0] smp_apic_timer_interrupt+0x19e/0x600 [ 59.120343][ C0] apic_timer_interrupt+0xf/0x20 [ 59.125431][ C0] native_safe_halt+0xe/0x10 [ 59.130188][ C0] default_idle+0x49/0x350 [ 59.134883][ C0] do_idle+0x393/0x690 [ 59.139111][ C0] cpu_startup_entry+0x14/0x20 [ 59.144026][ C0] start_kernel+0x867/0x8a1 [ 59.148680][ C0] secondary_startup_64+0xa4/0xb0 [ 59.153940][ C0] [ 59.156243][ C0] [ 59.156243][ C0] stack backtrace: [ 59.162128][ C0] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.6.0-syzkaller #0 [ 59.169642][ C0] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 59.179683][ C0] Call Trace: [ 59.182951][ C0] [ 59.185799][ C0] dump_stack+0x188/0x20d [ 59.190107][ C0] check_usage_forwards.cold+0x20/0x29 [ 59.195556][ C0] ? check_usage_backwards+0x4e0/0x4e0 [ 59.200990][ C0] ? stack_trace_consume_entry+0x160/0x160 [ 59.206777][ C0] ? __read_once_size_nocheck.constprop.0+0x10/0x10 [ 59.213345][ C0] ? save_trace+0x42/0x9f0 [ 59.217737][ C0] mark_lock+0x624/0xf10 [ 59.221970][ C0] ? check_usage_backwards+0x4e0/0x4e0 [ 59.227406][ C0] ? print_usage_bug+0x240/0x240 [ 59.232346][ C0] ? print_usage_bug+0x240/0x240 [ 59.237260][ C0] ? mark_lock+0x12b/0xf10 [ 59.241673][ C0] __lock_acquire+0x1d28/0x4e00 [ 59.246511][ C0] ? mark_held_locks+0xe0/0xe0 [ 59.251249][ C0] ? __wake_up_common_lock+0xde/0x130 [ 59.256595][ C0] lock_acquire+0x1f2/0x8f0 [ 59.261089][ C0] ? free_ioctx_users+0x2b/0x450 [ 59.266005][ C0] ? lock_release+0x800/0x800 [ 59.270655][ C0] ? lock_acquire+0x1f2/0x8f0 [ 59.275329][ C0] ? percpu_ref_switch_to_atomic_rcu+0x209/0x540 [ 59.281655][ C0] ? lock_release+0x800/0x800 [ 59.286319][ C0] ? _raw_spin_unlock_irqrestore+0x62/0xe0 [ 59.292105][ C0] _raw_spin_lock_irq+0x5b/0x80 [ 59.296935][ C0] ? free_ioctx_users+0x2b/0x450 [ 59.301846][ C0] free_ioctx_users+0x2b/0x450 [ 59.306592][ C0] percpu_ref_switch_to_atomic_rcu+0x494/0x540 [ 59.312747][ C0] rcu_core+0x59f/0x1370 [ 59.316976][ C0] ? __rcu_read_unlock+0x700/0x700 [ 59.322069][ C0] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 59.327597][ C0] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 59.333553][ C0] ? run_rebalance_domains+0x202/0x2c0 [ 59.339033][ C0] __do_softirq+0x26c/0x9f7 [ 59.343528][ C0] irq_exit+0x192/0x1d0 [ 59.347673][ C0] smp_apic_timer_interrupt+0x19e/0x600 [ 59.353386][ C0] apic_timer_interrupt+0xf/0x20 [ 59.358297][ C0] [ 59.361215][ C0] RIP: 0010:native_safe_halt+0xe/0x10 [ 59.366567][ C0] Code: cc cc cc cc cc cc cc cc cc cc cc cc e9 07 00 00 00 0f 00 2d 44 ae 5e 00 f4 c3 66 90 e9 07 00 00 00 0f 00 2d 34 ae 5e 00 fb f4 cc 41 56 41 55 41 54 55 53 e8 c3 07 97 f9 e8 9e 72 cb fb 0f 1f [ 59.386163][ C0] RSP: 0018:ffffffff89807d98 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 [ 59.394583][ C0] RAX: 1ffffffff13291af RBX: ffffffff898864c0 RCX: 0000000000000000 [ 59.402548][ C0] RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffffffff89886d84 [ 59.410498][ C0] RBP: dffffc0000000000 R08: ffffffff898864c0 R09: 0000000000000000 [ 59.418448][ C0] R10: 0000000000000000 R11: 0000000000000000 R12: fffffbfff1310c98 [ 59.426411][ C0] R13: 0000000000000000 R14: ffffffff8a883540 R15: 0000000000000000 [ 59.434376][ C0] default_idle+0x49/0x350 [ 59.438771][ C0] do_idle+0x393/0x690 [ 59.442921][ C0] ? rcu_read_lock_held+0x9c/0xb0 [ 59.447924][ C0] ? arch_cpu_idle_exit+0x70/0x70 [ 59.452924][ C0] ? schedule+0xe7/0x2a0 [ 59.457145][ C0] ? trace_init_perf_perm_irq_work_exit+0xe/0xe [ 59.463376][ C0] cpu_startup_entry+0x14/0x20 [ 59.469259][ C0] start_kernel+0x867/0x8a1 [ 59.473747][ C0] ? mem_encrypt_init+0x5/0x5 [ 59.478400][ C0] ? x86_family+0x3d/0x50 [ 59.482751][ C0] ? load_ucode_bsp+0x23d/0x27d [ 59.487579][ C0] secondary_startup_64+0xa4/0xb0