[ OK ] Reached target Login Prompts. [ OK ] Reached target Multi-User System. [ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... [ OK ] Started Update UTMP about System Runlevel Changes. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.0.198' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 60.982683][ C0] [ 60.985144][ C0] ======================================================== [ 60.993110][ C0] WARNING: possible irq lock inversion dependency detected [ 61.000313][ C0] 5.6.0-syzkaller #0 Not tainted [ 61.005230][ C0] -------------------------------------------------------- [ 61.012416][ C0] swapper/0/0 just changed the state of lock: [ 61.018547][ C0] ffff888094d6fcd8 (&ctx->ctx_lock){..-.}-{2:2}, at: free_ioctx_users+0x2b/0x450 [ 61.029078][ C0] but this lock took another, SOFTIRQ-unsafe lock in the past: [ 61.037060][ C0] (&pid->wait_pidfd){+.+.}-{2:2} [ 61.037070][ C0] [ 61.037070][ C0] [ 61.037070][ C0] and interrupts could create inverse lock ordering between them. [ 61.037070][ C0] [ 61.056744][ C0] [ 61.056744][ C0] other info that might help us debug this: [ 61.064782][ C0] Possible interrupt unsafe locking scenario: [ 61.064782][ C0] [ 61.073076][ C0] CPU0 CPU1 [ 61.078688][ C0] ---- ---- [ 61.084093][ C0] lock(&pid->wait_pidfd); [ 61.088577][ C0] local_irq_disable(); [ 61.095310][ C0] lock(&ctx->ctx_lock); [ 61.102132][ C0] lock(&pid->wait_pidfd); [ 61.109211][ C0] [ 61.112646][ C0] lock(&ctx->ctx_lock); [ 61.117141][ C0] [ 61.117141][ C0] *** DEADLOCK *** [ 61.117141][ C0] [ 61.125390][ C0] 2 locks held by swapper/0/0: [ 61.130124][ C0] #0: ffffffff899bbaa0 (rcu_callback){....}-{0:0}, at: rcu_core+0x520/0x1370 [ 61.138958][ C0] #1: ffffffff899bbbc0 (rcu_read_lock){....}-{1:2}, at: percpu_ref_switch_to_atomic_rcu+0x209/0x540 [ 61.149806][ C0] [ 61.149806][ C0] the shortest dependencies between 2nd lock and 1st lock: [ 61.159170][ C0] -> (&pid->wait_pidfd){+.+.}-{2:2} { [ 61.164655][ C0] HARDIRQ-ON-W at: [ 61.168723][ C0] lock_acquire+0x1f2/0x8f0 [ 61.175040][ C0] _raw_spin_lock+0x2a/0x40 [ 61.181359][ C0] proc_pid_make_inode+0x1f9/0x3c0 [ 61.188272][ C0] proc_pid_instantiate+0x51/0x150 [ 61.195233][ C0] proc_pid_lookup+0x1da/0x340 [ 61.201976][ C0] proc_root_lookup+0x20/0x60 [ 61.208525][ C0] __lookup_slow+0x256/0x490 [ 61.214917][ C0] walk_component+0x418/0x6a0 [ 61.221392][ C0] link_path_walk.part.0+0x4f1/0xb50 [ 61.228484][ C0] path_openat+0x25a/0x27d0 [ 61.234801][ C0] do_filp_open+0x192/0x260 [ 61.241103][ C0] do_sys_openat2+0x585/0x7d0 [ 61.247694][ C0] do_sys_open+0xc3/0x140 [ 61.253828][ C0] do_syscall_64+0xf6/0x7d0 [ 61.260186][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xb3 [ 61.267875][ C0] SOFTIRQ-ON-W at: [ 61.271923][ C0] lock_acquire+0x1f2/0x8f0 [ 61.278231][ C0] _raw_spin_lock+0x2a/0x40 [ 61.284535][ C0] proc_pid_make_inode+0x1f9/0x3c0 [ 61.291461][ C0] proc_pid_instantiate+0x51/0x150 [ 61.298386][ C0] proc_pid_lookup+0x1da/0x340 [ 61.304963][ C0] proc_root_lookup+0x20/0x60 [ 61.311478][ C0] __lookup_slow+0x256/0x490 [ 61.317919][ C0] walk_component+0x418/0x6a0 [ 61.324492][ C0] link_path_walk.part.0+0x4f1/0xb50 [ 61.331578][ C0] path_openat+0x25a/0x27d0 [ 61.337952][ C0] do_filp_open+0x192/0x260 [ 61.344254][ C0] do_sys_openat2+0x585/0x7d0 [ 61.350728][ C0] do_sys_open+0xc3/0x140 [ 61.356860][ C0] do_syscall_64+0xf6/0x7d0 [ 61.363168][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xb3 [ 61.370862][ C0] INITIAL USE at: [ 61.374821][ C0] lock_acquire+0x1f2/0x8f0 [ 61.381037][ C0] _raw_spin_lock_irqsave+0x8c/0xbf [ 61.387960][ C0] __wake_up_common_lock+0xb4/0x130 [ 61.394869][ C0] do_notify_parent+0x19e/0xe60 [ 61.401440][ C0] do_exit+0x238f/0x2dd0 [ 61.407403][ C0] call_usermodehelper_exec_async+0x507/0x710 [ 61.415192][ C0] ret_from_fork+0x24/0x30 [ 61.421360][ C0] } [ 61.423937][ C0] ... key at: [] __key.53827+0x0/0x40 [ 61.431451][ C0] ... acquired at: [ 61.436131][ C0] _raw_spin_lock+0x2a/0x40 [ 61.440793][ C0] io_submit_one+0xc1b/0x2ec0 [ 61.445618][ C0] __x64_sys_io_submit+0x1bd/0x540 [ 61.450877][ C0] do_syscall_64+0xf6/0x7d0 [ 61.455543][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xb3 [ 61.461578][ C0] [ 61.463883][ C0] -> (&ctx->ctx_lock){..-.}-{2:2} { [ 61.469055][ C0] IN-SOFTIRQ-W at: [ 61.473027][ C0] lock_acquire+0x1f2/0x8f0 [ 61.479169][ C0] _raw_spin_lock_irq+0x5b/0x80 [ 61.485643][ C0] free_ioctx_users+0x2b/0x450 [ 61.492031][ C0] percpu_ref_switch_to_atomic_rcu+0x494/0x540 [ 61.499811][ C0] rcu_core+0x59f/0x1370 [ 61.505677][ C0] __do_softirq+0x26c/0x9f7 [ 61.511801][ C0] irq_exit+0x192/0x1d0 [ 61.517769][ C0] smp_apic_timer_interrupt+0x19e/0x600 [ 61.524942][ C0] apic_timer_interrupt+0xf/0x20 [ 61.531606][ C0] native_safe_halt+0xe/0x10 [ 61.537828][ C0] default_idle+0x49/0x350 [ 61.543872][ C0] do_idle+0x393/0x690 [ 61.549565][ C0] cpu_startup_entry+0x14/0x20 [ 61.555964][ C0] start_kernel+0x867/0x8a1 [ 61.562118][ C0] secondary_startup_64+0xa4/0xb0 [ 61.568775][ C0] INITIAL USE at: [ 61.572646][ C0] lock_acquire+0x1f2/0x8f0 [ 61.578687][ C0] _raw_spin_lock_irq+0x5b/0x80 [ 61.585098][ C0] io_submit_one+0xbd6/0x2ec0 [ 61.591361][ C0] __x64_sys_io_submit+0x1bd/0x540 [ 61.598020][ C0] do_syscall_64+0xf6/0x7d0 [ 61.604067][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xb3 [ 61.611492][ C0] } [ 61.613992][ C0] ... key at: [] __key.55303+0x0/0x40 [ 61.621416][ C0] ... acquired at: [ 61.625211][ C0] mark_lock+0x624/0xf10 [ 61.629600][ C0] __lock_acquire+0x1d28/0x4e00 [ 61.634598][ C0] lock_acquire+0x1f2/0x8f0 [ 61.639250][ C0] _raw_spin_lock_irq+0x5b/0x80 [ 61.644248][ C0] free_ioctx_users+0x2b/0x450 [ 61.649160][ C0] percpu_ref_switch_to_atomic_rcu+0x494/0x540 [ 61.655460][ C0] rcu_core+0x59f/0x1370 [ 61.659869][ C0] __do_softirq+0x26c/0x9f7 [ 61.664520][ C0] irq_exit+0x192/0x1d0 [ 61.668821][ C0] smp_apic_timer_interrupt+0x19e/0x600 [ 61.674520][ C0] apic_timer_interrupt+0xf/0x20 [ 61.679671][ C0] native_safe_halt+0xe/0x10 [ 61.684541][ C0] default_idle+0x49/0x350 [ 61.689120][ C0] do_idle+0x393/0x690 [ 61.693387][ C0] cpu_startup_entry+0x14/0x20 [ 61.698307][ C0] start_kernel+0x867/0x8a1 [ 61.702968][ C0] secondary_startup_64+0xa4/0xb0 [ 61.708149][ C0] [ 61.710454][ C0] [ 61.710454][ C0] stack backtrace: [ 61.716322][ C0] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.6.0-syzkaller #0 [ 61.723836][ C0] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 61.733862][ C0] Call Trace: [ 61.737121][ C0] [ 61.739967][ C0] dump_stack+0x188/0x20d [ 61.744276][ C0] check_usage_forwards.cold+0x20/0x29 [ 61.749707][ C0] ? check_usage_backwards+0x4e0/0x4e0 [ 61.755141][ C0] ? stack_trace_consume_entry+0x160/0x160 [ 61.760919][ C0] ? __read_once_size_nocheck.constprop.0+0x10/0x10 [ 61.767482][ C0] ? save_trace+0x42/0x9f0 [ 61.771872][ C0] mark_lock+0x624/0xf10 [ 61.776093][ C0] ? check_usage_backwards+0x4e0/0x4e0 [ 61.781522][ C0] ? print_usage_bug+0x240/0x240 [ 61.786430][ C0] ? print_usage_bug+0x240/0x240 [ 61.791343][ C0] ? mark_lock+0x12b/0xf10 [ 61.795735][ C0] __lock_acquire+0x1d28/0x4e00 [ 61.800577][ C0] ? mark_held_locks+0xe0/0xe0 [ 61.805315][ C0] ? __wake_up_common_lock+0xde/0x130 [ 61.810671][ C0] lock_acquire+0x1f2/0x8f0 [ 61.815148][ C0] ? free_ioctx_users+0x2b/0x450 [ 61.820071][ C0] ? lock_release+0x800/0x800 [ 61.824720][ C0] ? lock_acquire+0x1f2/0x8f0 [ 61.829372][ C0] ? percpu_ref_switch_to_atomic_rcu+0x209/0x540 [ 61.835681][ C0] ? lock_release+0x800/0x800 [ 61.840329][ C0] ? _raw_spin_unlock_irqrestore+0x62/0xe0 [ 61.846107][ C0] _raw_spin_lock_irq+0x5b/0x80 [ 61.850932][ C0] ? free_ioctx_users+0x2b/0x450 [ 61.855841][ C0] free_ioctx_users+0x2b/0x450 [ 61.860580][ C0] percpu_ref_switch_to_atomic_rcu+0x494/0x540 [ 61.866774][ C0] rcu_core+0x59f/0x1370 [ 61.871113][ C0] ? __rcu_read_unlock+0x700/0x700 [ 61.876243][ C0] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 61.881775][ C0] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 61.887743][ C0] ? run_rebalance_domains+0x202/0x2c0 [ 61.893180][ C0] __do_softirq+0x26c/0x9f7 [ 61.897659][ C0] irq_exit+0x192/0x1d0 [ 61.901788][ C0] smp_apic_timer_interrupt+0x19e/0x600 [ 61.907568][ C0] apic_timer_interrupt+0xf/0x20 [ 61.912478][ C0] [ 61.915394][ C0] RIP: 0010:native_safe_halt+0xe/0x10 [ 61.920738][ C0] 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 3e b3 ca fb 0f 1f [ 61.940315][ C0] RSP: 0018:ffffffff89807d98 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13 [ 61.948700][ C0] RAX: 1ffffffff132925f RBX: ffffffff898864c0 RCX: 0000000000000000 [ 61.956668][ C0] RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffffffff89886d84 [ 61.964728][ C0] RBP: dffffc0000000000 R08: ffffffff898864c0 R09: 0000000000000000 [ 61.972677][ C0] R10: 0000000000000000 R11: 0000000000000000 R12: fffffbfff1310c98 [ 61.980636][ C0] R13: 0000000000000000 R14: ffffffff8a88e980 R15: 0000000000000000 [ 61.988612][ C0] default_idle+0x49/0x350 [ 61.993023][ C0] do_idle+0x393/0x690 [ 61.997068][ C0] ? rcu_read_lock_held+0x9c/0xb0 [ 62.002066][ C0] ? arch_cpu_idle_exit+0x70/0x70 [ 62.007066][ C0] ? schedule+0xe7/0x2a0 [ 62.011287][ C0] ? trace_init_perf_perm_irq_work_exit+0xe/0xe [ 62.017547][ C0] cpu_startup_entry+0x14/0x20 [ 62.022421][ C0] start_kernel+0x867/0x8a1 [ 62.026920][ C0] ? mem_encrypt_init+0x5/0x5 [ 62.031579][ C0] ? x86_family+0x3d/0x50 [ 62.035891][ C0] ? load_ucode_bsp+0x23d/0x27d [ 62.040827][ C0] secondary_startup_64+0xa4/0xb0