[ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... [ OK ] Started Update UTMP about System Runlevel Changes. Starting Load/Save RF Kill Switch Status... [ OK ] Started Load/Save RF Kill Switch Status. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.0.204' (ECDSA) to the list of known hosts. executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program syzkaller login: [ 53.359381] [ 53.361057] ====================================================== [ 53.367650] WARNING: possible circular locking dependency detected [ 53.374184] 4.19.197-syzkaller #0 Not tainted [ 53.378847] ------------------------------------------------------ [ 53.385841] kworker/1:2/3686 is trying to acquire lock: [ 53.393736] 000000009d5ccf44 (&sb->s_type->i_mutex_key#17){+.+.}, at: __generic_file_fsync+0xb0/0x1f0 [ 53.403116] [ 53.403116] but task is already holding lock: [ 53.409170] 000000004b39fc34 ((work_completion)(&dio->complete_work)){+.+.}, at: process_one_work+0x79c/0x1570 [ 53.419335] [ 53.419335] which lock already depends on the new lock. [ 53.419335] [ 53.427651] [ 53.427651] the existing dependency chain (in reverse order) is: [ 53.435271] [ 53.435271] -> #2 ((work_completion)(&dio->complete_work)){+.+.}: [ 53.443001] worker_thread+0x64c/0x1130 [ 53.447600] kthread+0x33f/0x460 [ 53.451501] ret_from_fork+0x24/0x30 [ 53.455729] [ 53.455729] -> #1 ((wq_completion)"dio/%s"sb->s_id){+.+.}: [ 53.462864] drain_workqueue+0x1a5/0x460 [ 53.467628] destroy_workqueue+0x75/0x790 [ 53.472314] __alloc_workqueue_key+0xb76/0xed0 [ 53.477421] sb_init_dio_done_wq+0x34/0x90 [ 53.482183] __blockdev_direct_IO+0x5f55/0xef40 [ 53.487645] fat_direct_IO+0x1d1/0x370 [ 53.492061] generic_file_direct_write+0x208/0x4a0 [ 53.497782] __generic_file_write_iter+0x2d0/0x610 [ 53.503498] generic_file_write_iter+0x3f8/0x730 [ 53.508857] aio_write+0x37f/0x5c0 [ 53.513021] io_submit_one+0xecd/0x20c0 [ 53.517519] __se_sys_io_submit+0x11b/0x4a0 [ 53.522466] do_syscall_64+0xf9/0x620 [ 53.527228] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 53.533121] [ 53.533121] -> #0 (&sb->s_type->i_mutex_key#17){+.+.}: [ 53.540081] down_write+0x34/0x90 [ 53.544077] __generic_file_fsync+0xb0/0x1f0 [ 53.549272] fat_file_fsync+0x73/0x200 [ 53.553725] vfs_fsync_range+0x13a/0x220 [ 53.558325] dio_complete+0x763/0xac0 [ 53.562672] process_one_work+0x864/0x1570 [ 53.567747] worker_thread+0x64c/0x1130 [ 53.572382] kthread+0x33f/0x460 [ 53.576295] ret_from_fork+0x24/0x30 [ 53.580539] [ 53.580539] other info that might help us debug this: [ 53.580539] [ 53.588682] Chain exists of: [ 53.588682] &sb->s_type->i_mutex_key#17 --> (wq_completion)"dio/%s"sb->s_id --> (work_completion)(&dio->complete_work) [ 53.588682] [ 53.604135] Possible unsafe locking scenario: [ 53.604135] [ 53.610627] CPU0 CPU1 [ 53.615302] ---- ---- [ 53.620149] lock((work_completion)(&dio->complete_work)); [ 53.625953] lock((wq_completion)"dio/%s"sb->s_id); [ 53.633577] lock((work_completion)(&dio->complete_work)); [ 53.641815] lock(&sb->s_type->i_mutex_key#17); [ 53.646580] [ 53.646580] *** DEADLOCK *** [ 53.646580] [ 53.652734] 2 locks held by kworker/1:2/3686: [ 53.657309] #0: 00000000c772878e ((wq_completion)"dio/%s"sb->s_id){+.+.}, at: process_one_work+0x767/0x1570 [ 53.667289] #1: 000000004b39fc34 ((work_completion)(&dio->complete_work)){+.+.}, at: process_one_work+0x79c/0x1570 [ 53.677884] [ 53.677884] stack backtrace: [ 53.682389] CPU: 1 PID: 3686 Comm: kworker/1:2 Not tainted 4.19.197-syzkaller #0 [ 53.690014] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 53.699388] Workqueue: dio/loop0 dio_aio_complete_work [ 53.704760] Call Trace: [ 53.707510] dump_stack+0x1fc/0x2ef [ 53.711151] print_circular_bug.constprop.0.cold+0x2d7/0x41e [ 53.716958] __lock_acquire+0x30c9/0x3ff0 [ 53.721111] ? pagevec_lookup_range_tag+0x3b/0x80 [ 53.725961] ? mark_held_locks+0xf0/0xf0 [ 53.730075] ? __filemap_fdatawait_range+0x356/0x510 [ 53.735365] ? wait_on_page_bit+0x3f0/0x3f0 [ 53.739700] ? delete_from_page_cache_batch+0xcc0/0xcc0 [ 53.745118] lock_acquire+0x170/0x3c0 [ 53.748928] ? __generic_file_fsync+0xb0/0x1f0 [ 53.753519] down_write+0x34/0x90 [ 53.756980] ? __generic_file_fsync+0xb0/0x1f0 [ 53.761571] __generic_file_fsync+0xb0/0x1f0 [ 53.765987] fat_file_fsync+0x73/0x200 [ 53.770066] ? fat_trim_fs+0x1030/0x1030 [ 53.774145] vfs_fsync_range+0x13a/0x220 [ 53.778242] dio_complete+0x763/0xac0 [ 53.782060] process_one_work+0x864/0x1570 [ 53.786305] ? pwq_dec_nr_in_flight+0x2d0/0x2d0 [ 53.790985] worker_thread+0x64c/0x1130 [ 53.795246] ? __kthread_parkme+0x133/0x1e0 [ 53.799576] ? process_one_work+0x1570/0x1570 [ 53.804084] kthread+0x33f/0x460 [ 53.807464] ? kthread_park+0x180/0x180 [ 53.811627] ret_from_fork+0x24/0x30 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program