syzbot


possible deadlock in generic_file_write_iter

Status: auto-closed as invalid on 2020/10/06 15:19
Reported-by: syzbot+1e6317a16c5ded6e76f5@syzkaller.appspotmail.com
First crash: 1453d, last: 1446d
Similar bugs (5)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream possible deadlock in generic_file_write_iter (2) fs 182 2351d 2364d 0/26 closed as invalid on 2018/02/13 19:29
linux-4.19 possible deadlock in generic_file_write_iter (2) C error 453 484d 1053d 0/1 upstream: reported C repro on 2021/07/06 07:41
linux-4.14 possible deadlock in generic_file_write_iter (2) C 20 451d 883d 0/1 upstream: reported C repro on 2021/12/23 04:07
upstream possible deadlock in generic_file_write_iter C 61506 2369d 2392d 3/26 fixed on 2017/11/28 03:36
linux-4.14 possible deadlock in generic_file_write_iter 3 1450d 1524d 0/1 auto-closed as invalid on 2020/10/01 23:22

Sample crash report:
FAT-fs (loop5): Filesystem has been set read-only
sctp: [Deprecated]: syz-executor.1 (pid 17804) Use of struct sctp_assoc_value in delayed_ack socket option.
Use struct sctp_sack_info instead
======================================================
WARNING: possible circular locking dependency detected
4.19.127-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.4/17772 is trying to acquire lock:
0000000092555b39 ((wq_completion)"dio/%s"sb->s_id){+.+.}, at: flush_workqueue+0xf7/0x1440 kernel/workqueue.c:2660

but task is already holding lock:
00000000e6aa0754 (&sb->s_type->i_mutex_key#26){++++}, at: inode_lock include/linux/fs.h:748 [inline]
00000000e6aa0754 (&sb->s_type->i_mutex_key#26){++++}, at: generic_file_write_iter+0x99/0x725 mm/filemap.c:3312

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&sb->s_type->i_mutex_key#26){++++}:
       inode_lock include/linux/fs.h:748 [inline]
       __generic_file_fsync+0xb0/0x1f0 fs/libfs.c:987
       fat_file_fsync+0x73/0x200 fs/fat/file.c:198
       vfs_fsync_range+0x138/0x220 fs/sync.c:197
       generic_write_sync include/linux/fs.h:2747 [inline]
       dio_complete+0x47c/0x9e0 fs/direct-io.c:329
       process_one_work+0x892/0x1580 kernel/workqueue.c:2155
       worker_thread+0x96/0xe20 kernel/workqueue.c:2298
       kthread+0x30b/0x410 kernel/kthread.c:246
       ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415

-> #1 ((work_completion)(&dio->complete_work)){+.+.}:
       worker_thread+0x96/0xe20 kernel/workqueue.c:2298
       kthread+0x30b/0x410 kernel/kthread.c:246
       ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415

-> #0 ((wq_completion)"dio/%s"sb->s_id){+.+.}:
       flush_workqueue+0x126/0x1440 kernel/workqueue.c:2663
       drain_workqueue+0x1a7/0x460 kernel/workqueue.c:2828
       destroy_workqueue+0x75/0x6f0 kernel/workqueue.c:4172
       __alloc_workqueue_key+0xc09/0xe20 kernel/workqueue.c:4149
       sb_init_dio_done_wq+0x34/0x90 fs/direct-io.c:623
       do_blockdev_direct_IO fs/direct-io.c:1284 [inline]
       __blockdev_direct_IO+0x6445/0xfe24 fs/direct-io.c:1418
       blockdev_direct_IO include/linux/fs.h:3056 [inline]
       fat_direct_IO+0x1cc/0x2f0 fs/fat/inode.c:282
       generic_file_direct_write+0x207/0x490 mm/filemap.c:3065
       __generic_file_write_iter+0x2d4/0x610 mm/filemap.c:3244
       generic_file_write_iter+0x3f4/0x725 mm/filemap.c:3315
       call_write_iter include/linux/fs.h:1821 [inline]
       aio_write+0x346/0x530 fs/aio.c:1573
       __io_submit_one fs/aio.c:1850 [inline]
       io_submit_one+0x1005/0x20c0 fs/aio.c:1901
       __do_sys_io_submit fs/aio.c:1945 [inline]
       __se_sys_io_submit+0x142/0x4a0 fs/aio.c:1916
       do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
       entry_SYSCALL_64_after_hwframe+0x49/0xbe

other info that might help us debug this:

Chain exists of:
  (wq_completion)"dio/%s"sb->s_id --> (work_completion)(&dio->complete_work) --> &sb->s_type->i_mutex_key#26

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&sb->s_type->i_mutex_key#26);
                               lock((work_completion)(&dio->complete_work));
                               lock(&sb->s_type->i_mutex_key#26);
  lock((wq_completion)"dio/%s"sb->s_id);

 *** DEADLOCK ***

1 lock held by syz-executor.4/17772:
 #0: 00000000e6aa0754 (&sb->s_type->i_mutex_key#26){++++}, at: inode_lock include/linux/fs.h:748 [inline]
 #0: 00000000e6aa0754 (&sb->s_type->i_mutex_key#26){++++}, at: generic_file_write_iter+0x99/0x725 mm/filemap.c:3312

stack backtrace:
CPU: 1 PID: 17772 Comm: syz-executor.4 Not tainted 4.19.127-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1fc/0x2fe lib/dump_stack.c:118
 print_circular_bug.isra.0.cold+0x2dc/0x425 kernel/locking/lockdep.c:1221
 check_prev_add kernel/locking/lockdep.c:1865 [inline]
 check_prevs_add kernel/locking/lockdep.c:1978 [inline]
 validate_chain kernel/locking/lockdep.c:2419 [inline]
 __lock_acquire+0x3145/0x4380 kernel/locking/lockdep.c:3415
 lock_acquire+0x170/0x3c0 kernel/locking/lockdep.c:3907
 flush_workqueue+0x126/0x1440 kernel/workqueue.c:2663
 drain_workqueue+0x1a7/0x460 kernel/workqueue.c:2828
 destroy_workqueue+0x75/0x6f0 kernel/workqueue.c:4172
 __alloc_workqueue_key+0xc09/0xe20 kernel/workqueue.c:4149
 sb_init_dio_done_wq+0x34/0x90 fs/direct-io.c:623
 do_blockdev_direct_IO fs/direct-io.c:1284 [inline]
 __blockdev_direct_IO+0x6445/0xfe24 fs/direct-io.c:1418
 blockdev_direct_IO include/linux/fs.h:3056 [inline]
 fat_direct_IO+0x1cc/0x2f0 fs/fat/inode.c:282
 generic_file_direct_write+0x207/0x490 mm/filemap.c:3065
 __generic_file_write_iter+0x2d4/0x610 mm/filemap.c:3244
 generic_file_write_iter+0x3f4/0x725 mm/filemap.c:3315
 call_write_iter include/linux/fs.h:1821 [inline]
 aio_write+0x346/0x530 fs/aio.c:1573
 __io_submit_one fs/aio.c:1850 [inline]
 io_submit_one+0x1005/0x20c0 fs/aio.c:1901
 __do_sys_io_submit fs/aio.c:1945 [inline]
 __se_sys_io_submit+0x142/0x4a0 fs/aio.c:1916
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45ca69
Code: 0d b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f6656d42c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000d1
RAX: ffffffffffffffda RBX: 00000000004e0d40 RCX: 000000000045ca69
RDX: 0000000020000540 RSI: 0000000000000006 RDI: 00007f6656d20000
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000006
R13: 00000000000001fb R14: 00000000004c4486 R15: 00007f6656d436d4
FAT-fs (loop5): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop5): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop5): Filesystem has been set read-only
FAT-fs (loop5): error, invalid access to FAT (entry 0x00000020)
sctp: [Deprecated]: syz-executor.1 (pid 17846) Use of struct sctp_assoc_value in delayed_ack socket option.
Use struct sctp_sack_info instead
FAT-fs (loop5): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop5): Filesystem has been set read-only
FAT-fs (loop5): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop4): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop4): Filesystem has been set read-only
FAT-fs (loop5): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop5): Filesystem has been set read-only
FAT-fs (loop5): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop4): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop4): Filesystem has been set read-only
sctp: [Deprecated]: syz-executor.1 (pid 17934) Use of struct sctp_assoc_value in delayed_ack socket option.
Use struct sctp_sack_info instead
FAT-fs (loop5): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop4): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop5): Filesystem has been set read-only
FAT-fs (loop4): Filesystem has been set read-only
FAT-fs (loop5): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop4): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop4): Filesystem has been set read-only
FAT-fs (loop5): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop5): Filesystem has been set read-only
FAT-fs (loop5): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop4): error, invalid access to FAT (entry 0x00000020)
sctp: [Deprecated]: syz-executor.1 (pid 18018) Use of struct sctp_assoc_value in delayed_ack socket option.
Use struct sctp_sack_info instead
FAT-fs (loop4): Filesystem has been set read-only
FAT-fs (loop5): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop5): Filesystem has been set read-only
FAT-fs (loop5): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop4): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop5): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop4): Filesystem has been set read-only
FAT-fs (loop5): Filesystem has been set read-only
FAT-fs (loop5): error, invalid access to FAT (entry 0x00000020)
sctp: [Deprecated]: syz-executor.1 (pid 18075) Use of struct sctp_assoc_value in delayed_ack socket option.
Use struct sctp_sack_info instead
sctp: [Deprecated]: syz-executor.3 (pid 18089) Use of struct sctp_assoc_value in delayed_ack socket option.
Use struct sctp_sack_info instead
sctp: [Deprecated]: syz-executor.1 (pid 18092) Use of struct sctp_assoc_value in delayed_ack socket option.
Use struct sctp_sack_info instead
FAT-fs (loop4): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop4): Filesystem has been set read-only
FAT-fs (loop5): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop5): Filesystem has been set read-only
FAT-fs (loop5): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop5): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop4): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop4): Filesystem has been set read-only
sctp: [Deprecated]: syz-executor.3 (pid 18139) Use of struct sctp_assoc_value in delayed_ack socket option.
Use struct sctp_sack_info instead
FAT-fs (loop5): Filesystem has been set read-only
FAT-fs (loop5): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop4): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop5): error, invalid access to FAT (entry 0x00000020)
sctp: [Deprecated]: syz-executor.1 (pid 18178) Use of struct sctp_assoc_value in delayed_ack socket option.
Use struct sctp_sack_info instead
FAT-fs (loop4): Filesystem has been set read-only
FAT-fs (loop5): Filesystem has been set read-only
FAT-fs (loop5): error, invalid access to FAT (entry 0x00000020)
sctp: [Deprecated]: syz-executor.3 (pid 18182) Use of struct sctp_assoc_value in delayed_ack socket option.
Use struct sctp_sack_info instead
FAT-fs (loop4): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop4): Filesystem has been set read-only
FAT-fs (loop5): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop5): Filesystem has been set read-only
FAT-fs (loop5): error, invalid access to FAT (entry 0x00000020)
sctp: [Deprecated]: syz-executor.1 (pid 18233) Use of struct sctp_assoc_value in delayed_ack socket option.
Use struct sctp_sack_info instead
FAT-fs (loop5): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop5): Filesystem has been set read-only
FAT-fs (loop5): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop4): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop4): Filesystem has been set read-only
sctp: [Deprecated]: syz-executor.1 (pid 18260) Use of struct sctp_assoc_value in delayed_ack socket option.
Use struct sctp_sack_info instead
FAT-fs (loop5): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop4): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop4): Filesystem has been set read-only
FAT-fs (loop5): Filesystem has been set read-only
FAT-fs (loop5): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop4): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop4): Filesystem has been set read-only
sctp: [Deprecated]: syz-executor.1 (pid 18321) Use of struct sctp_assoc_value in delayed_ack socket option.
Use struct sctp_sack_info instead
FAT-fs (loop5): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop5): Filesystem has been set read-only
FAT-fs (loop5): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop4): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop5): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop5): Filesystem has been set read-only
FAT-fs (loop4): Filesystem has been set read-only
FAT-fs (loop5): error, invalid access to FAT (entry 0x00000020)
sctp: [Deprecated]: syz-executor.1 (pid 18374) Use of struct sctp_assoc_value in delayed_ack socket option.
Use struct sctp_sack_info instead
FAT-fs (loop5): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop5): Filesystem has been set read-only
FAT-fs (loop5): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop4): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop4): Filesystem has been set read-only
FAT-fs (loop5): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop5): Filesystem has been set read-only
FAT-fs (loop4): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop5): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop4): Filesystem has been set read-only
team0: Device ipvlan1 failed to register rx_handler
FAT-fs (loop4): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop4): Filesystem has been set read-only
FAT-fs (loop5): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop5): Filesystem has been set read-only
FAT-fs (loop5): error, invalid access to FAT (entry 0x00000020)
team0: Device ipvlan1 failed to register rx_handler
FAT-fs (loop5): error, invalid access to FAT (entry 0x00000020)
sctp_setsockopt_delayed_ack: 1 callbacks suppressed
sctp: [Deprecated]: syz-executor.1 (pid 18506) Use of struct sctp_assoc_value in delayed_ack socket option.
Use struct sctp_sack_info instead
FAT-fs (loop5): Filesystem has been set read-only
FAT-fs (loop5): error, invalid access to FAT (entry 0x00000020)

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/06/08 15:18 linux-4.19.y 106fa147d3da 7604bb03 .config console log report ci2-linux-4-19
2020/06/02 22:47 linux-4.19.y 2d16cf4817bc 52fd7b7d .config console log report ci2-linux-4-19
2020/06/02 19:31 linux-4.19.y 2d16cf4817bc 52fd7b7d .config console log report ci2-linux-4-19
2020/06/01 08:33 linux-4.19.y 2d16cf4817bc a0331e89 .config console log report ci2-linux-4-19
* Struck through repros no longer work on HEAD.