[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 87.816893][ T27] audit: type=1800 audit(1577452448.914:25): pid=9318 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 87.839167][ T27] audit: type=1800 audit(1577452448.914:26): pid=9318 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 87.861579][ T27] audit: type=1800 audit(1577452448.924:27): pid=9318 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="restorecond" dev="sda1" ino=2436 res=0 [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.0.174' (ECDSA) to the list of known hosts. syzkaller login: [ 711.593582][ C1] hrtimer: interrupt took 45550 ns [ 803.373559][ C1] rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: [ 803.380657][ C1] (detected by 1, t=10502 jiffies, g=9361, q=32) [ 803.387077][ C1] rcu: All QSes seen, last rcu_preempt kthread activity 10503 (4295017469-4295006966), jiffies_till_next_fqs=1, root ->qsmask 0x0 [ 803.400444][ C1] syz-executor419 R running task 28008 9485 9480 0x00000000 [ 803.408428][ C1] Call Trace: [ 803.411713][ C1] [ 803.414639][ C1] sched_show_task.cold+0x2ee/0x35d [ 803.419843][ C1] ? can_nice.part.0+0x20/0x20 [ 803.424685][ C1] ? __sanitizer_cov_trace_cmp8+0x18/0x20 [ 803.430776][ C1] rcu_sched_clock_irq.cold+0xb92/0xcc0 [ 803.436416][ C1] update_process_times+0x2d/0x70 [ 803.441565][ C1] tick_sched_handle+0xa2/0x190 [ 803.446442][ C1] tick_sched_timer+0x53/0x140 [ 803.451214][ C1] __hrtimer_run_queues+0x364/0xe40 [ 803.456446][ C1] ? tick_sched_do_timer+0x1b0/0x1b0 [ 803.462368][ C1] ? hrtimer_init+0x330/0x330 [ 803.467048][ C1] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 803.472769][ C1] ? ktime_get_update_offsets_now+0x2ce/0x430 [ 803.478838][ C1] hrtimer_interrupt+0x314/0x770 [ 803.483867][ C1] smp_apic_timer_interrupt+0x160/0x610 [ 803.489690][ C1] apic_timer_interrupt+0xf/0x20 [ 803.494621][ C1] [ 803.497609][ C1] RIP: 0010:__local_bh_enable_ip+0x18e/0x270 [ 803.503936][ C1] Code: 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 0f 85 df 00 00 00 48 83 3d 27 32 4c 08 00 0f 84 8f 00 00 00 fb 66 0f 1f 44 00 00 <65> 8b 05 33 a2 ba 7e 85 c0 74 7f 5b 41 5c 41 5d 5d c3 80 3d 9c 62 [ 803.523722][ C1] RSP: 0000:ffffc90002047d28 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 [ 803.532238][ C1] RAX: 1ffffffff13275cd RBX: 0000000000000200 RCX: 0000000000000000 [ 803.540421][ C1] RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffff8880a283ad5c [ 803.549102][ C1] RBP: ffffc90002047d40 R08: ffff8880a283a4c0 R09: 0000000000000000 [ 803.557687][ C1] R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff812abb4c [ 803.565675][ C1] R13: ffff8880a283a4c0 R14: 0000000000000000 R15: ffffc90002047f58 [ 803.573739][ C1] ? fpu__clear+0x17c/0x440 [ 803.578271][ C1] ? __local_bh_enable_ip+0x15a/0x270 [ 803.583643][ C1] fpu__clear+0x19c/0x440 [ 803.588114][ C1] do_signal+0x9d2/0x1700 [ 803.592538][ C1] ? setup_sigcontext+0x7d0/0x7d0 [ 803.597634][ C1] ? __bad_area_nosemaphore+0xb3/0x420 [ 803.603246][ C1] ? exit_to_usermode_loop+0x43/0x380 [ 803.608837][ C1] ? lockdep_hardirqs_on+0x421/0x5e0 [ 803.614183][ C1] ? trace_hardirqs_on+0x67/0x240 [ 803.619212][ C1] exit_to_usermode_loop+0x286/0x380 [ 803.624508][ C1] prepare_exit_to_usermode+0x321/0x3a0 [ 803.630052][ C1] ret_from_intr+0x26/0x36 [ 803.634463][ C1] RIP: 0033:0x400da0 [ 803.638364][ C1] Code: 4c 00 e8 63 bf 0a 00 bf f8 ae 6d 00 48 83 3f 00 75 08 5d e9 62 ff ff ff 66 90 b8 00 00 00 00 48 85 c0 74 ee ff d0 eb ea 66 90 <48> 83 ec 08 48 8b 46 10 64 8b 14 25 d0 ff ff ff 85 d2 74 0e 48 2d [ 803.658099][ C1] RSP: 002b:00007f3d3abe8578 EFLAGS: 00000202 [ 803.664173][ C1] RAX: 0000000000000000 RBX: 00000000006dcc28 RCX: 0000000000406cc7 [ 803.672158][ C1] RDX: 00007f3d3abe8580 RSI: 00007f3d3abe86b0 RDI: 000000000000000b [ 803.680136][ C1] RBP: 00000000006dcc20 R08: 00007f3d3abe8b20 R09: 00000000006dcc20 [ 803.688207][ C1] R10: 0000000000000000 R11: 0000000000000000 R12: 00000000006dcc2c [ 803.696354][ C1] R13: 00007ffc594f05cf R14: 00007f3d3abe99c0 R15: 00000000006dcc20 [ 803.704368][ C1] rcu: rcu_preempt kthread starved for 10535 jiffies! g9361 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 [ 803.715632][ C1] rcu: RCU grace-period kthread stack dump: [ 803.721530][ C1] rcu_preempt R running task 29248 10 2 0x80004000 [ 803.729444][ C1] Call Trace: [ 803.733300][ C1] __schedule+0x934/0x1f90 [ 803.737872][ C1] ? firmware_map_remove+0x1a0/0x1a0 [ 803.743269][ C1] ? _raw_spin_unlock_irqrestore+0x66/0xe0 [ 803.749092][ C1] ? schedule_timeout+0x490/0xc60 [ 803.754211][ C1] ? lockdep_hardirqs_on+0x421/0x5e0 [ 803.759503][ C1] schedule+0xdc/0x2b0 [ 803.763578][ C1] schedule_timeout+0x49a/0xc60 [ 803.768445][ C1] ? _raw_spin_unlock_irqrestore+0x66/0xe0 [ 803.774259][ C1] ? usleep_range+0x170/0x170 [ 803.779069][ C1] ? trace_hardirqs_on+0x67/0x240 [ 803.784296][ C1] ? __next_timer_interrupt+0x1a0/0x1a0 [ 803.790008][ C1] ? swake_up_one+0x60/0x60 [ 803.794547][ C1] rcu_gp_kthread+0xa10/0x1b20 [ 803.799346][ C1] ? rcu_note_context_switch+0x1980/0x1980 [ 803.805421][ C1] ? trace_hardirqs_on+0x67/0x240 [ 803.810540][ C1] ? __sanitizer_cov_trace_const_cmp1+0x1a/0x20 [ 803.816944][ C1] ? __kthread_parkme+0x108/0x1c0 [ 803.822067][ C1] ? __kasan_check_read+0x11/0x20 [ 803.827183][ C1] kthread+0x361/0x430 [ 803.831345][ C1] ? rcu_note_context_switch+0x1980/0x1980 [ 803.837147][ C1] ? kthread_mod_delayed_work+0x1f0/0x1f0 [ 803.842877][ C1] ret_from_fork+0x24/0x30