[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 60.561725][ T26] audit: type=1800 audit(1583416368.875:25): pid=8582 uid=0 auid=4294967295 ses=4294967295 subj=_ op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 60.580677][ T26] audit: type=1800 audit(1583416368.885:26): pid=8582 uid=0 auid=4294967295 ses=4294967295 subj=_ op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 60.632741][ T26] audit: type=1800 audit(1583416368.885:27): pid=8582 uid=0 auid=4294967295 ses=4294967295 subj=_ 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 '10.128.1.60' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 72.070000][ T8739] IPVS: ftp: loaded support on port[0] = 21 executing program executing program [ 72.492567][ C1] hrtimer: interrupt took 38930 ns executing program executing program [ 73.076867][ T8758] [ 73.079222][ T8758] ====================================================== [ 73.086213][ T8758] WARNING: possible circular locking dependency detected [ 73.093335][ T8758] 5.6.0-rc3-syzkaller #0 Not tainted [ 73.098587][ T8758] ------------------------------------------------------ [ 73.105580][ T8758] syz-executor374/8758 is trying to acquire lock: [ 73.112076][ T8758] ffffffff892c9f18 (cpu_hotplug_lock.rw_sem){++++}, at: __static_key_slow_dec+0x14/0x90 [ 73.121789][ T8758] [ 73.121789][ T8758] but task is already holding lock: [ 73.129138][ T8758] ffff88808438c7d8 (&mm->mmap_sem#2){++++}, at: vm_mmap_pgoff+0xf6/0x1d0 [ 73.138015][ T8758] [ 73.138015][ T8758] which lock already depends on the new lock. [ 73.138015][ T8758] [ 73.148399][ T8758] [ 73.148399][ T8758] the existing dependency chain (in reverse order) is: [ 73.157388][ T8758] [ 73.157388][ T8758] -> #2 (&mm->mmap_sem#2){++++}: [ 73.165953][ T8758] lock_acquire+0x154/0x250 [ 73.171059][ T8758] down_write+0x57/0x140 [ 73.175794][ T8758] mpol_rebind_mm+0x37/0x210 [ 73.180876][ T8758] cpuset_attach+0x35f/0x4c0 [ 73.186134][ T8758] cgroup_migrate_execute+0x7ac/0xff0 [ 73.192107][ T8758] cgroup_migrate+0x181/0x190 [ 73.197280][ T8758] cgroup_attach_task+0x786/0xa10 [ 73.202898][ T8758] __cgroup1_procs_write+0x257/0x390 [ 73.208689][ T8758] cgroup1_procs_write+0x2a/0x40 [ 73.214121][ T8758] cgroup_file_write+0x223/0x5f0 [ 73.219572][ T8758] kernfs_fop_write+0x3f0/0x4f0 [ 73.224919][ T8758] __vfs_write+0xb8/0x740 [ 73.229741][ T8758] vfs_write+0x270/0x580 [ 73.234476][ T8758] ksys_write+0x117/0x220 [ 73.239298][ T8758] __x64_sys_write+0x7b/0x90 [ 73.244381][ T8758] do_syscall_64+0xf7/0x1c0 [ 73.249396][ T8758] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 73.255779][ T8758] [ 73.255779][ T8758] -> #1 (&cpuset_rwsem){++++}: [ 73.262708][ T8758] lock_acquire+0x154/0x250 [ 73.267704][ T8758] cpuset_read_lock+0x3e/0x130 [ 73.273055][ T8758] __sched_setscheduler+0x624/0x1b00 [ 73.278835][ T8758] sched_setscheduler_nocheck+0x125/0x240 [ 73.285049][ T8758] __kthread_create_on_node+0x2eb/0x3b0 [ 73.291090][ T8758] kthread_create_on_node+0x72/0xa0 [ 73.296786][ T8758] create_worker+0x396/0x890 [ 73.301878][ T8758] workqueue_prepare_cpu+0x98/0x110 [ 73.307570][ T8758] cpuhp_invoke_callback+0x4c9/0x8b0 [ 73.313363][ T8758] _cpu_up+0x307/0x550 [ 73.317948][ T8758] do_cpu_up+0x159/0x1a0 [ 73.322698][ T8758] cpu_up+0x18/0x20 [ 73.327006][ T8758] smp_init+0x107/0x29a [ 73.331671][ T8758] kernel_init_freeable+0x2f2/0x429 [ 73.337363][ T8758] kernel_init+0x11/0x290 [ 73.342182][ T8758] ret_from_fork+0x24/0x30 [ 73.347172][ T8758] [ 73.347172][ T8758] -> #0 (cpu_hotplug_lock.rw_sem){++++}: [ 73.354952][ T8758] validate_chain+0x1507/0x7be0 [ 73.360314][ T8758] __lock_acquire+0xc5a/0x1bc0 [ 73.365571][ T8758] lock_acquire+0x154/0x250 [ 73.370569][ T8758] cpus_read_lock+0x3e/0x130 [ 73.375653][ T8758] __static_key_slow_dec+0x14/0x90 [ 73.381259][ T8758] static_key_slow_dec+0x50/0xa0 [ 73.386687][ T8758] sw_perf_event_destroy+0x78/0x170 [ 73.392377][ T8758] _free_event+0x825/0xdc0 [ 73.397300][ T8758] perf_mmap_close+0xc04/0xea0 [ 73.402563][ T8758] __do_munmap+0x1006/0x14b0 [ 73.407666][ T8758] mmap_region+0x8c8/0x1c40 [ 73.412670][ T8758] do_mmap+0xa8f/0x1100 [ 73.417321][ T8758] vm_mmap_pgoff+0x13d/0x1d0 [ 73.422418][ T8758] ksys_mmap_pgoff+0x45b/0x540 [ 73.427676][ T8758] __x64_sys_mmap+0x103/0x120 [ 73.432876][ T8758] do_syscall_64+0xf7/0x1c0 [ 73.437872][ T8758] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 73.444256][ T8758] [ 73.444256][ T8758] other info that might help us debug this: [ 73.444256][ T8758] [ 73.454464][ T8758] Chain exists of: [ 73.454464][ T8758] cpu_hotplug_lock.rw_sem --> &cpuset_rwsem --> &mm->mmap_sem#2 [ 73.454464][ T8758] [ 73.467977][ T8758] Possible unsafe locking scenario: [ 73.467977][ T8758] [ 73.475401][ T8758] CPU0 CPU1 [ 73.480859][ T8758] ---- ---- [ 73.486314][ T8758] lock(&mm->mmap_sem#2); [ 73.490710][ T8758] lock(&cpuset_rwsem); [ 73.497528][ T8758] lock(&mm->mmap_sem#2); [ 73.504436][ T8758] lock(cpu_hotplug_lock.rw_sem); [ 73.509516][ T8758] [ 73.509516][ T8758] *** DEADLOCK *** [ 73.509516][ T8758] [ 73.517665][ T8758] 1 lock held by syz-executor374/8758: [ 73.523126][ T8758] #0: ffff88808438c7d8 (&mm->mmap_sem#2){++++}, at: vm_mmap_pgoff+0xf6/0x1d0 [ 73.532040][ T8758] [ 73.532040][ T8758] stack backtrace: [ 73.537910][ T8758] CPU: 1 PID: 8758 Comm: syz-executor374 Not tainted 5.6.0-rc3-syzkaller #0 [ 73.546555][ T8758] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 73.556586][ T8758] Call Trace: [ 73.559855][ T8758] dump_stack+0x1fb/0x318 [ 73.564179][ T8758] print_circular_bug+0xc3f/0xe70 [ 73.569179][ T8758] ? stack_trace_save+0xb1/0x150 [ 73.574092][ T8758] ? save_trace+0x4b/0x9f0 [ 73.578485][ T8758] check_noncircular+0x206/0x3a0 [ 73.583405][ T8758] validate_chain+0x1507/0x7be0 [ 73.588244][ T8758] ? lockdep_hardirqs_on+0x4a5/0x7a0 [ 73.593519][ T8758] ? __kasan_check_read+0x11/0x20 [ 73.598537][ T8758] ? mark_lock+0x107/0x1650 [ 73.603017][ T8758] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 73.608452][ T8758] ? check_preemption_disabled+0x37/0x260 [ 73.614148][ T8758] ? retint_kernel+0x2b/0x2b [ 73.618733][ T8758] __lock_acquire+0xc5a/0x1bc0 [ 73.623474][ T8758] ? finish_lock_switch+0x31/0x40 [ 73.628477][ T8758] ? __schedule+0x887/0xcd0 [ 73.632963][ T8758] ? trace_lock_acquire+0x15b/0x1d0 [ 73.638139][ T8758] lock_acquire+0x154/0x250 [ 73.642624][ T8758] ? __static_key_slow_dec+0x14/0x90 [ 73.647915][ T8758] cpus_read_lock+0x3e/0x130 [ 73.652483][ T8758] ? __static_key_slow_dec+0x14/0x90 [ 73.657742][ T8758] __static_key_slow_dec+0x14/0x90 [ 73.662828][ T8758] static_key_slow_dec+0x50/0xa0 [ 73.667740][ T8758] sw_perf_event_destroy+0x78/0x170 [ 73.672930][ T8758] ? perf_swevent_del+0xd0/0xd0 [ 73.677755][ T8758] _free_event+0x825/0xdc0 [ 73.682149][ T8758] perf_mmap_close+0xc04/0xea0 [ 73.686888][ T8758] ? __might_sleep+0x8f/0x100 [ 73.691545][ T8758] ? perf_mmap_open+0x1c0/0x1c0 [ 73.696371][ T8758] __do_munmap+0x1006/0x14b0 [ 73.700935][ T8758] mmap_region+0x8c8/0x1c40 [ 73.705417][ T8758] do_mmap+0xa8f/0x1100 [ 73.709550][ T8758] vm_mmap_pgoff+0x13d/0x1d0 [ 73.714116][ T8758] ksys_mmap_pgoff+0x45b/0x540 [ 73.718957][ T8758] ? trace_irq_disable_rcuidle+0x23/0x1e0 [ 73.724738][ T8758] __x64_sys_mmap+0x103/0x120 [ 73.729393][ T8758] do_syscall_64+0xf7/0x1c0 [ 73.733888][ T8758] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 73.739753][ T8758] RIP: 0033:0x4473b9 [ 73.743636][ T8758] Code: e8 4c bb 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 5b 07 fc ff c3 66 2e 0f 1f 84 00 00 00 00 [ 73.763308][ T8758] RSP: 002b:00007f0272a71da8 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 [ 73.771694][ T8758] RAX: ffffffffffffffda RBX: 00000000006dcc38 RCX: 00000000004473b9 executing program [ 73.779680][ T8758] RDX: 0000000000000000 RSI: 0000000000003000 RDI: 0000000020ffd000 [ 73.787637][ T8758] RBP: 00000000006dcc30 R08: 0000000000000004 R09: 0000000000000000 [ 73.795615][ T8758] R10: 0000000000000011 R11: 0000000000000246 R12: 00000000006dcc3c [ 73.803563][ T8758] R13: 00007ffcae9c6f0f R14: 00007f0272a729c0 R15: 0000000000000000 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program