[ 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 '10.128.0.207' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 59.356362][ C0] [ 59.358838][ C0] ======================================================== [ 59.366010][ C0] WARNING: possible irq lock inversion dependency detected [ 59.373412][ C0] 5.6.0-syzkaller #0 Not tainted [ 59.378323][ C0] -------------------------------------------------------- [ 59.385497][ C0] swapper/0/0 just changed the state of lock: [ 59.391545][ C0] ffff888091b33cd8 (&ctx->ctx_lock){..-.}-{2:2}, at: free_ioctx_users+0x2b/0x450 [ 59.401451][ C0] but this lock took another, SOFTIRQ-unsafe lock in the past: [ 59.409022][ C0] (&pid->wait_pidfd){+.+.}-{2:2} [ 59.409030][ C0] [ 59.409030][ C0] [ 59.409030][ C0] and interrupts could create inverse lock ordering between them. [ 59.409030][ C0] [ 59.428321][ C0] [ 59.428321][ C0] other info that might help us debug this: [ 59.436358][ C0] Possible interrupt unsafe locking scenario: [ 59.436358][ C0] [ 59.444653][ C0] CPU0 CPU1 [ 59.449993][ C0] ---- ---- [ 59.455331][ C0] lock(&pid->wait_pidfd); [ 59.459814][ C0] local_irq_disable(); [ 59.466540][ C0] lock(&ctx->ctx_lock); [ 59.473381][ C0] lock(&pid->wait_pidfd); [ 59.480387][ C0] [ 59.483818][ C0] lock(&ctx->ctx_lock); [ 59.488299][ C0] [ 59.488299][ C0] *** DEADLOCK *** [ 59.488299][ C0] [ 59.496440][ C0] 2 locks held by swapper/0/0: [ 59.501218][ C0] #0: ffffffff899bbaa0 (rcu_callback){....}-{0:0}, at: rcu_core+0x520/0x1370 [ 59.510198][ C0] #1: ffffffff899bbbc0 (rcu_read_lock){....}-{1:2}, at: percpu_ref_switch_to_atomic_rcu+0x209/0x540 [ 59.521199][ C0] [ 59.521199][ C0] the shortest dependencies between 2nd lock and 1st lock: [ 59.530589][ C0] -> (&pid->wait_pidfd){+.+.}-{2:2} { [ 59.536030][ C0] HARDIRQ-ON-W at: [ 59.540114][ C0] lock_acquire+0x1f2/0x8f0 [ 59.546424][ C0] _raw_spin_lock+0x2a/0x40 [ 59.552726][ C0] proc_pid_make_inode+0x1f9/0x3c0 [ 59.559648][ C0] proc_pid_instantiate+0x51/0x150 [ 59.566560][ C0] proc_pid_lookup+0x1da/0x340 [ 59.573129][ C0] proc_root_lookup+0x20/0x60 [ 59.579605][ C0] __lookup_slow+0x256/0x490 [ 59.585997][ C0] walk_component+0x418/0x6a0 [ 59.592520][ C0] link_path_walk.part.0+0x4f1/0xb50 [ 59.599613][ C0] path_openat+0x25a/0x27d0 [ 59.605924][ C0] do_filp_open+0x192/0x260 [ 59.612234][ C0] do_sys_openat2+0x585/0x7d0 [ 59.618728][ C0] do_sys_open+0xc3/0x140 [ 59.624868][ C0] do_syscall_64+0xf6/0x7d0 [ 59.631190][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xb3 [ 59.638894][ C0] SOFTIRQ-ON-W at: [ 59.642954][ C0] lock_acquire+0x1f2/0x8f0 [ 59.649633][ C0] _raw_spin_lock+0x2a/0x40 [ 59.656050][ C0] proc_pid_make_inode+0x1f9/0x3c0 [ 59.662980][ C0] proc_pid_instantiate+0x51/0x150 [ 59.669901][ C0] proc_pid_lookup+0x1da/0x340 [ 59.676474][ C0] proc_root_lookup+0x20/0x60 [ 59.682951][ C0] __lookup_slow+0x256/0x490 [ 59.689353][ C0] walk_component+0x418/0x6a0 [ 59.695832][ C0] link_path_walk.part.0+0x4f1/0xb50 [ 59.702917][ C0] path_openat+0x25a/0x27d0 [ 59.709219][ C0] do_filp_open+0x192/0x260 [ 59.715523][ C0] do_sys_openat2+0x585/0x7d0 [ 59.721998][ C0] do_sys_open+0xc3/0x140 [ 59.728124][ C0] do_syscall_64+0xf6/0x7d0 [ 59.734428][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xb3 [ 59.742112][ C0] INITIAL USE at: [ 59.746087][ C0] lock_acquire+0x1f2/0x8f0 [ 59.752326][ C0] _raw_spin_lock_irqsave+0x8c/0xbf [ 59.759245][ C0] __wake_up_common_lock+0xb4/0x130 [ 59.766173][ C0] do_notify_parent+0x19e/0xe60 [ 59.772736][ C0] do_exit+0x238f/0x2dd0 [ 59.778693][ C0] call_usermodehelper_exec_async+0x507/0x710 [ 59.786472][ C0] ret_from_fork+0x24/0x30 [ 59.792591][ C0] } [ 59.795159][ C0] ... key at: [] __key.53827+0x0/0x40 [ 59.802773][ C0] ... acquired at: [ 59.806663][ C0] _raw_spin_lock+0x2a/0x40 [ 59.811314][ C0] io_submit_one+0xc1b/0x2ec0 [ 59.816150][ C0] __ia32_compat_sys_io_submit+0x1bf/0x530 [ 59.822121][ C0] do_fast_syscall_32+0x270/0xe90 [ 59.827291][ C0] entry_SYSENTER_compat+0x70/0x7f [ 59.832734][ C0] [ 59.835047][ C0] -> (&ctx->ctx_lock){..-.}-{2:2} { [ 59.840222][ C0] IN-SOFTIRQ-W at: [ 59.844300][ C0] lock_acquire+0x1f2/0x8f0 [ 59.850442][ C0] _raw_spin_lock_irq+0x5b/0x80 [ 59.857180][ C0] free_ioctx_users+0x2b/0x450 [ 59.863573][ C0] percpu_ref_switch_to_atomic_rcu+0x494/0x540 [ 59.871355][ C0] rcu_core+0x59f/0x1370 [ 59.877242][ C0] __do_softirq+0x26c/0x9f7 [ 59.883405][ C0] irq_exit+0x192/0x1d0 [ 59.889185][ C0] smp_apic_timer_interrupt+0x19e/0x600 [ 59.896353][ C0] apic_timer_interrupt+0xf/0x20 [ 59.902915][ C0] native_safe_halt+0xe/0x10 [ 59.909138][ C0] default_idle+0x49/0x350 [ 59.915180][ C0] do_idle+0x393/0x690 [ 59.920872][ C0] cpu_startup_entry+0x14/0x20 [ 59.927267][ C0] start_kernel+0x867/0x8a1 [ 59.933395][ C0] secondary_startup_64+0xa4/0xb0 [ 59.940040][ C0] INITIAL USE at: [ 59.943916][ C0] lock_acquire+0x1f2/0x8f0 [ 59.949958][ C0] _raw_spin_lock_irq+0x5b/0x80 [ 59.956347][ C0] io_submit_one+0xbd6/0x2ec0 [ 59.962559][ C0] __ia32_compat_sys_io_submit+0x1bf/0x530 [ 59.969963][ C0] do_fast_syscall_32+0x270/0xe90 [ 59.976523][ C0] entry_SYSENTER_compat+0x70/0x7f [ 59.983163][ C0] } [ 59.985659][ C0] ... key at: [] __key.55303+0x0/0x40 [ 59.993109][ C0] ... acquired at: [ 59.996905][ C0] mark_lock+0x624/0xf10 [ 60.001312][ C0] __lock_acquire+0x1d28/0x4e00 [ 60.006326][ C0] lock_acquire+0x1f2/0x8f0 [ 60.011012][ C0] _raw_spin_lock_irq+0x5b/0x80 [ 60.016026][ C0] free_ioctx_users+0x2b/0x450 [ 60.020954][ C0] percpu_ref_switch_to_atomic_rcu+0x494/0x540 [ 60.027262][ C0] rcu_core+0x59f/0x1370 [ 60.031835][ C0] __do_softirq+0x26c/0x9f7 [ 60.036489][ C0] irq_exit+0x192/0x1d0 [ 60.040792][ C0] smp_apic_timer_interrupt+0x19e/0x600 [ 60.046495][ C0] apic_timer_interrupt+0xf/0x20 [ 60.051668][ C0] native_safe_halt+0xe/0x10 [ 60.056425][ C0] default_idle+0x49/0x350 [ 60.061069][ C0] do_idle+0x393/0x690 [ 60.065294][ C0] cpu_startup_entry+0x14/0x20 [ 60.070331][ C0] start_kernel+0x867/0x8a1 [ 60.074988][ C0] secondary_startup_64+0xa4/0xb0 [ 60.080156][ C0] [ 60.082460][ C0] [ 60.082460][ C0] stack backtrace: [ 60.088329][ C0] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.6.0-syzkaller #0 [ 60.095842][ C0] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 60.105880][ C0] Call Trace: [ 60.109178][ C0] [ 60.112020][ C0] dump_stack+0x188/0x20d [ 60.116347][ C0] check_usage_forwards.cold+0x20/0x29 [ 60.121876][ C0] ? check_usage_backwards+0x4e0/0x4e0 [ 60.127314][ C0] ? stack_trace_consume_entry+0x160/0x160 [ 60.133195][ C0] ? __read_once_size_nocheck.constprop.0+0x10/0x10 [ 60.139762][ C0] ? save_trace+0x42/0x9f0 [ 60.144155][ C0] mark_lock+0x624/0xf10 [ 60.148638][ C0] ? check_usage_backwards+0x4e0/0x4e0 [ 60.154070][ C0] ? print_usage_bug+0x240/0x240 [ 60.158993][ C0] ? print_usage_bug+0x240/0x240 [ 60.163918][ C0] ? mark_lock+0x12b/0xf10 [ 60.168328][ C0] __lock_acquire+0x1d28/0x4e00 [ 60.173157][ C0] ? mark_held_locks+0xe0/0xe0 [ 60.177899][ C0] ? __wake_up_common_lock+0xde/0x130 [ 60.183257][ C0] lock_acquire+0x1f2/0x8f0 [ 60.187750][ C0] ? free_ioctx_users+0x2b/0x450 [ 60.192665][ C0] ? lock_release+0x800/0x800 [ 60.197344][ C0] ? lock_acquire+0x1f2/0x8f0 [ 60.202007][ C0] ? percpu_ref_switch_to_atomic_rcu+0x209/0x540 [ 60.208313][ C0] ? lock_release+0x800/0x800 [ 60.212969][ C0] ? _raw_spin_unlock_irqrestore+0x62/0xe0 [ 60.218853][ C0] _raw_spin_lock_irq+0x5b/0x80 [ 60.223690][ C0] ? free_ioctx_users+0x2b/0x450 [ 60.228613][ C0] free_ioctx_users+0x2b/0x450 [ 60.233355][ C0] percpu_ref_switch_to_atomic_rcu+0x494/0x540 [ 60.239496][ C0] rcu_core+0x59f/0x1370 [ 60.243761][ C0] ? __rcu_read_unlock+0x700/0x700 [ 60.248860][ C0] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 60.254661][ C0] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 60.260729][ C0] ? run_rebalance_domains+0x202/0x2c0 [ 60.266180][ C0] __do_softirq+0x26c/0x9f7 [ 60.270800][ C0] irq_exit+0x192/0x1d0 [ 60.275034][ C0] smp_apic_timer_interrupt+0x19e/0x600 [ 60.281516][ C0] apic_timer_interrupt+0xf/0x20 [ 60.286431][ C0] [ 60.289363][ C0] RIP: 0010:native_safe_halt+0xe/0x10 [ 60.294706][ 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 fe b2 ca fb 0f 1f [ 60.314287][ C0] RSP: 0018:ffffffff89807d98 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13 [ 60.322703][ C0] RAX: 1ffffffff132925f RBX: ffffffff898864c0 RCX: 0000000000000000 [ 60.331294][ C0] RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffffffff89886d84 [ 60.339253][ C0] RBP: dffffc0000000000 R08: ffffffff898864c0 R09: 0000000000000000 [ 60.347233][ C0] R10: 0000000000000000 R11: 0000000000000000 R12: fffffbfff1310c98 [ 60.355186][ C0] R13: 0000000000000000 R14: ffffffff8a88e980 R15: 0000000000000000 [ 60.363171][ C0] default_idle+0x49/0x350 [ 60.367722][ C0] do_idle+0x393/0x690 [ 60.371928][ C0] ? rcu_read_lock_held+0x9c/0xb0 [ 60.376941][ C0] ? arch_cpu_idle_exit+0x70/0x70 [ 60.382048][ C0] ? schedule+0xe7/0x2a0 [ 60.386276][ C0] ? trace_init_perf_perm_irq_work_exit+0xe/0xe [ 60.392599][ C0] cpu_startup_entry+0x14/0x20 [ 60.397360][ C0] start_kernel+0x867/0x8a1 [ 60.402056][ C0] ? mem_encrypt_init+0x5/0x5 [ 60.406733][ C0] ? x86_family+0x3d/0x50 [ 60.411243][ C0] ? load_ucode_bsp+0x23d/0x27d [ 60.416268][ C0] secondary_startup_64+0xa4/0xb0