[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. [ 26.245854] kauditd_printk_skb: 7 callbacks suppressed [ 26.245864] audit: type=1800 audit(1541857832.142:29): pid=5497 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="rc.local" dev="sda1" ino=2432 res=0 [ 26.271276] audit: type=1800 audit(1541857832.152:30): pid=5497 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="rmnologin" dev="sda1" ino=2423 res=0 Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.0.64' (ECDSA) to the list of known hosts. executing program executing program executing program executing program executing program executing program syzkaller login: [ 89.805637] [ 89.807290] ====================================================== [ 89.813587] WARNING: possible circular locking dependency detected [ 89.819988] 4.20.0-rc1-next-20181109+ #109 Not tainted [ 89.825244] ------------------------------------------------------ [ 89.831550] syz-executor814/5659 is trying to acquire lock: [ 89.837238] 000000003390ea37 ((wq_completion)"dio/%s"sb->s_id){+.+.}, at: flush_workqueue+0x2db/0x1e10 [ 89.846688] [ 89.846688] but task is already holding lock: [ 89.852641] 00000000a013271a (&sb->s_type->i_mutex_key#10){+.+.}, at: ext4_file_write_iter+0x2a1/0x1420 [ 89.862348] [ 89.862348] which lock already depends on the new lock. [ 89.862348] [ 89.870763] [ 89.870763] the existing dependency chain (in reverse order) is: [ 89.878368] [ 89.878368] -> #2 (&sb->s_type->i_mutex_key#10){+.+.}: [ 89.885123] down_write+0x8a/0x130 [ 89.889174] __generic_file_fsync+0xb5/0x200 [ 89.894089] ext4_sync_file+0xa45/0x1500 [ 89.898731] vfs_fsync_range+0x140/0x220 [ 89.903304] dio_complete+0x75c/0x9e0 [ 89.907608] dio_aio_complete_work+0x20/0x30 [ 89.912521] process_one_work+0xc8b/0x1c40 [ 89.917257] worker_thread+0x17f/0x1390 [ 89.921736] kthread+0x35a/0x440 [ 89.925610] ret_from_fork+0x3a/0x50 [ 89.929916] [ 89.929916] -> #1 ((work_completion)(&dio->complete_work)){+.+.}: [ 89.937712] process_one_work+0xc0a/0x1c40 [ 89.942585] worker_thread+0x17f/0x1390 [ 89.947066] kthread+0x35a/0x440 [ 89.950944] ret_from_fork+0x3a/0x50 [ 89.955160] [ 89.955160] -> #0 ((wq_completion)"dio/%s"sb->s_id){+.+.}: [ 89.962385] lock_acquire+0x1ed/0x520 [ 89.966690] flush_workqueue+0x30a/0x1e10 [ 89.971454] drain_workqueue+0x2a9/0x640 [ 89.976036] destroy_workqueue+0xc6/0x9c0 [ 89.980701] sb_init_dio_done_wq+0x74/0x90 [ 89.985441] do_blockdev_direct_IO+0x9e7/0xa340 [ 89.990614] __blockdev_direct_IO+0x9d/0xc6 [ 89.995494] ext4_direct_IO+0xbdc/0x2220 [ 90.000069] generic_file_direct_write+0x275/0x4b0 [ 90.005556] __generic_file_write_iter+0x2ff/0x630 [ 90.011001] ext4_file_write_iter+0x390/0x1420 [ 90.016088] aio_write+0x3b1/0x610 [ 90.020134] io_submit_one+0xaa1/0xf80 [ 90.024526] __x64_sys_io_submit+0x1ab/0x580 [ 90.029442] do_syscall_64+0x1b9/0x820 [ 90.033836] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 90.039525] [ 90.039525] other info that might help us debug this: [ 90.039525] [ 90.047650] Chain exists of: [ 90.047650] (wq_completion)"dio/%s"sb->s_id --> (work_completion)(&dio->complete_work) --> &sb->s_type->i_mutex_key#10 [ 90.047650] [ 90.063002] Possible unsafe locking scenario: [ 90.063002] [ 90.069050] CPU0 CPU1 [ 90.073872] ---- ---- [ 90.078524] lock(&sb->s_type->i_mutex_key#10); [ 90.083259] lock((work_completion)(&dio->complete_work)); [ 90.091525] lock(&sb->s_type->i_mutex_key#10); [ 90.098799] lock((wq_completion)"dio/%s"sb->s_id); [ 90.103889] [ 90.103889] *** DEADLOCK *** [ 90.103889] [ 90.109944] 1 lock held by syz-executor814/5659: [ 90.114792] #0: 00000000a013271a (&sb->s_type->i_mutex_key#10){+.+.}, at: ext4_file_write_iter+0x2a1/0x1420 [ 90.124775] [ 90.124775] stack backtrace: [ 90.129261] CPU: 0 PID: 5659 Comm: syz-executor814 Not tainted 4.20.0-rc1-next-20181109+ #109 [ 90.137918] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 90.147263] Call Trace: [ 90.149842] dump_stack+0x244/0x39d [ 90.153457] ? dump_stack_print_info.cold.1+0x20/0x20 [ 90.158630] ? vprintk_func+0x85/0x181 [ 90.162515] print_circular_bug.isra.35.cold.56+0x1bd/0x27d [ 90.168206] ? save_trace+0xe0/0x290 [ 90.171920] __lock_acquire+0x3399/0x4c20 [ 90.176054] ? kasan_check_read+0x11/0x20 [ 90.180190] ? mark_held_locks+0x130/0x130 [ 90.184415] ? __cpu_to_node+0x7d/0xa0 [ 90.188516] ? mark_held_locks+0x130/0x130 [ 90.192748] ? enqueue_entity+0x34b/0x20d0 [ 90.196980] ? __lock_acquire+0x62f/0x4c20 [ 90.201205] ? put_prev_task_fair+0x80/0x80 [ 90.205508] ? select_task_rq_fair+0x63a/0x30b0 [ 90.210343] ? mark_held_locks+0x130/0x130 [ 90.214561] lock_acquire+0x1ed/0x520 [ 90.218352] ? flush_workqueue+0x2db/0x1e10 [ 90.222668] ? lock_release+0xa10/0xa10 [ 90.226632] ? lockdep_init_map+0x9/0x10 [ 90.230676] ? __init_waitqueue_head+0x9e/0x150 [ 90.235343] ? init_wait_entry+0x1c0/0x1c0 [ 90.239707] ? __lock_is_held+0xb5/0x140 [ 90.243756] flush_workqueue+0x30a/0x1e10 [ 90.247900] ? flush_workqueue+0x2db/0x1e10 [ 90.252208] ? lock_acquire+0x1ed/0x520 [ 90.256164] ? drain_workqueue+0xa9/0x640 [ 90.260312] ? lock_release+0xa10/0xa10 [ 90.264275] ? lock_release+0xa10/0xa10 [ 90.268248] ? perf_trace_sched_process_exec+0x860/0x860 [ 90.273685] ? cancel_delayed_work+0x3e0/0x3e0 [ 90.278254] ? graph_lock+0x270/0x270 [ 90.282044] ? __mutex_lock+0x85e/0x16f0 [ 90.286151] ? __mutex_lock+0x85e/0x16f0 [ 90.290210] ? drain_workqueue+0xa9/0x640 [ 90.294351] ? __alloc_workqueue_key+0x79a/0x10a0 [ 90.299192] ? find_held_lock+0x36/0x1c0 [ 90.303251] ? drain_workqueue+0x13f/0x640 [ 90.307479] ? lock_downgrade+0x900/0x900 [ 90.311621] ? lock_downgrade+0x900/0x900 [ 90.315753] ? try_to_wake_up+0x11c/0x1490 [ 90.319982] ? graph_lock+0x270/0x270 [ 90.323858] ? kasan_check_write+0x14/0x20 [ 90.328086] ? __mutex_unlock_slowpath+0x197/0x8c0 [ 90.332995] ? __mutex_unlock_slowpath+0x197/0x8c0 [ 90.337930] ? wait_for_completion+0x8a0/0x8a0 [ 90.342498] ? wait_for_completion+0x8a0/0x8a0 [ 90.347244] ? pwq_activate_delayed_work+0x650/0x650 [ 90.352354] drain_workqueue+0x2a9/0x640 [ 90.356409] ? drain_workqueue+0x2a9/0x640 [ 90.360633] ? __alloc_workqueue_key+0xb88/0x10a0 [ 90.365465] ? flush_workqueue+0x1e10/0x1e10 [ 90.369860] ? workqueue_sysfs_register+0x3f0/0x3f0 [ 90.374871] ? save_stack+0x43/0xd0 [ 90.378500] ? kasan_kmalloc+0xc7/0xe0 [ 90.382377] ? kasan_slab_alloc+0x12/0x20 [ 90.386523] ? kmem_cache_alloc+0x12e/0x730 [ 90.390832] ? __blockdev_direct_IO+0x9d/0xc6 [ 90.395311] ? ext4_direct_IO+0xbdc/0x2220 [ 90.399531] ? generic_file_direct_write+0x275/0x4b0 [ 90.404619] ? __generic_file_write_iter+0x2ff/0x630 [ 90.409868] ? ext4_file_write_iter+0x390/0x1420 [ 90.414636] ? aio_write+0x3b1/0x610 [ 90.418423] ? io_submit_one+0xaa1/0xf80 [ 90.422480] ? do_syscall_64+0x1b9/0x820 [ 90.426528] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 90.431892] destroy_workqueue+0xc6/0x9c0 [ 90.436031] ? wq_watchdog_timer_fn+0x810/0x810 [ 90.440695] ? graph_lock+0x270/0x270 [ 90.444495] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 90.450019] ? __lock_is_held+0xb5/0x140 [ 90.454073] ? rcu_read_lock_sched_held+0x14f/0x180 [ 90.459195] ? kmem_cache_alloc+0x33a/0x730 [ 90.463509] ? graph_lock+0x270/0x270 [ 90.467302] sb_init_dio_done_wq+0x74/0x90 [ 90.471526] do_blockdev_direct_IO+0x9e7/0xa340 [ 90.476183] ? __lock_is_held+0xb5/0x140 [ 90.480233] ? write_end_fn+0xf0/0xf0 [ 90.484072] ? ext4_get_block_trans+0x2e0/0x2e0 [ 90.488738] ? do_direct_IO+0xc110/0xc110 [ 90.492882] ? lock_downgrade+0x900/0x900 [ 90.497022] ? check_preemption_disabled+0x48/0x280 [ 90.502038] ? xas_clear_mark+0x2f5/0x360 [ 90.506176] ? filemap_fault+0x25f0/0x25f0 [ 90.510399] ? xas_create_range+0x5c0/0x5c0 [ 90.514795] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 90.520414] ? xas_clear_mark+0x2f5/0x360 [ 90.524570] ? graph_lock+0x270/0x270 [ 90.528355] ? print_usage_bug+0xc0/0xc0 [ 90.532405] ? __delete_from_page_cache+0x6db/0x10e0 [ 90.537499] ? graph_lock+0x270/0x270 [ 90.541473] ? find_held_lock+0x36/0x1c0 [ 90.545531] ? __lock_is_held+0xb5/0x140 [ 90.549582] ? kasan_check_read+0x11/0x20 [ 90.553720] ? perf_trace_sched_process_exec+0x860/0x860 [ 90.559165] ? pagevec_lookup_entries+0x3a/0x80 [ 90.563824] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 90.569353] ? invalidate_inode_pages2_range+0x15ef/0x1cb0 [ 90.574975] ? pagecache_isize_extended+0x440/0x440 [ 90.579985] ? ext4_mark_inode_dirty+0xb10/0xb10 [ 90.584729] ? graph_lock+0x270/0x270 [ 90.588517] ? do_page_fault+0xed/0x7d1 [ 90.592479] ? __lock_is_held+0xb5/0x140 [ 90.596522] ? graph_lock+0x270/0x270 [ 90.600376] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 90.605919] ? check_preemption_disabled+0x48/0x280 [ 90.610930] ? __lock_is_held+0xb5/0x140 [ 90.614978] ? ext4_get_block_trans+0x2e0/0x2e0 [ 90.619737] __blockdev_direct_IO+0x9d/0xc6 [ 90.624050] ? write_end_fn+0xf0/0xf0 [ 90.627897] ext4_direct_IO+0xbdc/0x2220 [ 90.631958] ? ext4_get_block_trans+0x2e0/0x2e0 [ 90.636615] ? ext4_iomap_end+0x810/0x810 [ 90.640748] ? wbc_attach_and_unlock_inode+0xa30/0xa30 [ 90.646015] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 90.651543] ? __filemap_fdatawrite_range+0x2ab/0x4a0 [ 90.656727] ? delete_from_page_cache_batch+0x1630/0x1630 [ 90.662253] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 90.667839] ? file_update_time+0xe4/0x640 [ 90.672079] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 90.677618] ? filemap_check_errors+0xd8/0x110 [ 90.682206] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 90.687731] generic_file_direct_write+0x275/0x4b0 [ 90.692655] __generic_file_write_iter+0x2ff/0x630 [ 90.697577] ext4_file_write_iter+0x390/0x1420 [ 90.702254] ? __fget+0x4d1/0x740 [ 90.705701] ? ext4_file_mmap+0x410/0x410 [ 90.709834] ? find_held_lock+0x36/0x1c0 [ 90.713888] ? aio_write+0x4ce/0x610 [ 90.717591] ? lock_downgrade+0x900/0x900 [ 90.721726] ? __lock_is_held+0xb5/0x140 [ 90.725887] ? rcu_read_lock_sched_held+0x14f/0x180 [ 90.730889] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 90.736425] ? __sb_start_write+0x1b2/0x370 [ 90.740738] aio_write+0x3b1/0x610 [ 90.744265] ? aio_complete_rw+0x640/0x640 [ 90.748486] ? lock_downgrade+0x900/0x900 [ 90.752625] ? kasan_check_read+0x11/0x20 [ 90.756874] ? rcu_dynticks_curr_cpu_in_eqs+0xa2/0x170 [ 90.762315] io_submit_one+0xaa1/0xf80 [ 90.766190] ? aio_poll+0x1420/0x1420 [ 90.769977] ? __might_fault+0x12b/0x1e0 [ 90.774026] ? lock_downgrade+0x900/0x900 [ 90.778160] ? perf_trace_sched_process_exec+0x860/0x860 [ 90.783609] ? blk_lld_busy+0xa0/0xa0 [ 90.787407] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 90.792937] __x64_sys_io_submit+0x1ab/0x580 [ 90.797334] ? __ia32_sys_io_destroy+0x580/0x580 [ 90.802077] ? lockdep_hardirqs_on+0x3bb/0x5b0 [ 90.806647] ? __ia32_sys_read+0xb0/0xb0 [ 90.810829] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 90.816195] ? trace_hardirqs_off_caller+0x300/0x300 [ 90.821297] ? do_sys_ftruncate+0x449/0x550 [ 90.825605] do_syscall_64+0x1b9/0x820 [ 90.829478] ? __ia32_sys_io_destroy+0x580/0x580 [ 90.834233] ? do_syscall_64+0x1b9/0x820 [ 90.838293] ? entry_SYSCALL_64_after_hwframe+0x3e/0xbe [ 90.843647] ? syscall_return_slowpath+0x5e0/0x5e0 [ 90.848648] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 90.853489] ? trace_hardirqs_on_caller+0x310/0x310 [ 90.858493] ? prepare_exit_to_usermode+0x3b0/0x3b0 [ 90.863643] ? prepare_exit_to_usermode+0x291/0x3b0 [ 90.868820] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 90.873832] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 90.879023] RIP: 0033:0x441a99 [ 90.882203] Code: e8 7c e7 ff ff 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 db 08 fc ff c3 66 2e 0f 1f 84 00 00 00 00 [ 90.901087] RSP: 002b:00007ffd033b8e18 EFLAGS: 00000246 ORIG_RAX: 00000000000000d1 [ 90.908843] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441a99 [ 90.916113] RDX: 0000000020000540 RSI: 0000000000000008 RDI: 00007f845e05d000 [ 90.923373] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 [ 90.930631] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 [ 90.938022] R13: 0000000000402890 R14: 0000000000000000 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 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 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 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 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 [ 94.377399] syz-executor814 (5924) used greatest stack depth: 14136 bytes left 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 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 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 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 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 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 [ 98.427616] syz-executor814 (6238) used greatest stack depth: 12408 bytes left 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 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