possible deadlock in ext4_file_write_iter
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syzbot
Jun 2, 2020, 8:40:17 PM6/2/20
to syzkaller...@googlegroups.com
Hello,
syzbot found the following crash on:
HEAD commit: 2d16cf48 Linux 4.19.125
git tree: linux-4.19.y
console output: https://syzkaller.appspot.com/x/log.txt?x=10a9e516100000
kernel config: https://syzkaller.appspot.com/x/.config?x=60c13d6e8857c508
dashboard link: https://syzkaller.appspot.com/bug?extid=ccc15f2cc5d9484439c7
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
Unfortunately, I don't have any reproducer for this crash yet.
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+ccc15f...@syzkaller.appspotmail.com
======================================================
WARNING: possible circular locking dependency detected
4.19.125-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.3/1887 is trying to acquire lock:
00000000c1f2fa45 ((wq_completion)"dio/%s"sb->s_id){+.+.}, at: flush_workqueue+0xf7/0x1440 kernel/workqueue.c:2660
FAT-fs (loop2): error, invalid access to FAT (entry 0x00000020)
but task is already holding lock:
00000000891b42bf (&sb->s_type->i_mutex_key#9){++++}, at: inode_trylock include/linux/fs.h:768 [inline]
00000000891b42bf (&sb->s_type->i_mutex_key#9){++++}, at: ext4_file_write_iter+0x21f/0xf60 fs/ext4/file.c:238
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (&sb->s_type->i_mutex_key#9){++++}:
inode_lock include/linux/fs.h:748 [inline]
__generic_file_fsync+0xb0/0x1f0 fs/libfs.c:987
ext4_sync_file+0xa28/0x1430 fs/ext4/fsync.c:120
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
FAT-fs (loop2): Filesystem has been set read-only
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
FAT-fs (loop2): error, invalid access to FAT (entry 0x00000020)
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
sb_init_dio_done_wq+0x72/0x90 fs/direct-io.c:634
do_blockdev_direct_IO fs/direct-io.c:1284 [inline]
__blockdev_direct_IO+0x6445/0xfe24 fs/direct-io.c:1418
ext4_direct_IO_write fs/ext4/inode.c:3769 [inline]
ext4_direct_IO+0xa8b/0x1ab0 fs/ext4/inode.c:3902
generic_file_direct_write+0x207/0x490 mm/filemap.c:3065
__generic_file_write_iter+0x2d4/0x610 mm/filemap.c:3244
ext4_file_write_iter+0x2fe/0xf60 fs/ext4/file.c:272
FAT-fs (loop5): error, invalid access to FAT (entry 0x00000020)
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
attempt to access beyond end of device
loop2: rw=34817, want=157, limit=116
other info that might help us debug this:
FAT-fs (loop5): Filesystem has been set read-only
Chain exists of:
(wq_completion)"dio/%s"sb->s_id --> (work_completion)(&dio->complete_work) --> &sb->s_type->i_mutex_key#9
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&sb->s_type->i_mutex_key#9);
lock((work_completion)(&dio->complete_work));
lock(&sb->s_type->i_mutex_key#9);
FAT-fs (loop5): error, invalid access to FAT (entry 0x00000020)
lock((wq_completion)"dio/%s"sb->s_id);
*** DEADLOCK ***
1 lock held by syz-executor.3/1887:
#0: 00000000891b42bf (&sb->s_type->i_mutex_key#9){++++}, at: inode_trylock include/linux/fs.h:768 [inline]
#0: 00000000891b42bf (&sb->s_type->i_mutex_key#9){++++}, at: ext4_file_write_iter+0x21f/0xf60 fs/ext4/file.c:238
stack backtrace:
CPU: 0 PID: 1887 Comm: syz-executor.3 Not tainted 4.19.125-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
attempt to access beyond end of device
drain_workqueue+0x1a7/0x460 kernel/workqueue.c:2828
destroy_workqueue+0x75/0x6f0 kernel/workqueue.c:4172
loop5: rw=34817, want=157, limit=116
sb_init_dio_done_wq+0x72/0x90 fs/direct-io.c:634
do_blockdev_direct_IO fs/direct-io.c:1284 [inline]
__blockdev_direct_IO+0x6445/0xfe24 fs/direct-io.c:1418
FAT-fs (loop4): error, invalid access to FAT (entry 0x00000020)
ext4_direct_IO_write fs/ext4/inode.c:3769 [inline]
ext4_direct_IO+0xa8b/0x1ab0 fs/ext4/inode.c:3902
generic_file_direct_write+0x207/0x490 mm/filemap.c:3065
FAT-fs (loop4): Filesystem has been set read-only
__generic_file_write_iter+0x2d4/0x610 mm/filemap.c:3244
ext4_file_write_iter+0x2fe/0xf60 fs/ext4/file.c:272
call_write_iter include/linux/fs.h:1821 [inline]
aio_write+0x346/0x530 fs/aio.c:1573
FAT-fs (loop4): error, invalid access to FAT (entry 0x00000020)
__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:00007f2ae55ebc78 EFLAGS: 00000246 ORIG_RAX: 00000000000000d1
RAX: ffffffffffffffda RBX: 00000000004e0d40 RCX: 000000000045ca69
RDX: 0000000020000540 RSI: 0000000000000006 RDI: 00007f2ae55a8000
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000001fb R14: 00000000004c4486 R15: 00007f2ae55ec6d4
FAT-fs (loop2): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop2): Filesystem has been set read-only
FAT-fs (loop2): error, invalid access to FAT (entry 0x00000020)
attempt to access beyond end of device
loop2: rw=34817, want=157, limit=116
9pnet: p9_errstr2errno: server reported unknown error �ȢV�
Can not set IPV6_FL_F_REFLECT if flowlabel_consistency sysctl is enable
Can not set IPV6_FL_F_REFLECT if flowlabel_consistency sysctl is enable
Can not set IPV6_FL_F_REFLECT if flowlabel_consistency sysctl is enable
Can not set IPV6_FL_F_REFLECT if flowlabel_consistency sysctl is enable
9pnet: p9_errstr2errno: server reported unknown error �ȢV�
---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.
syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
syzbot found the following crash on:
HEAD commit: 2d16cf48 Linux 4.19.125
git tree: linux-4.19.y
console output: https://syzkaller.appspot.com/x/log.txt?x=10a9e516100000
kernel config: https://syzkaller.appspot.com/x/.config?x=60c13d6e8857c508
dashboard link: https://syzkaller.appspot.com/bug?extid=ccc15f2cc5d9484439c7
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
Unfortunately, I don't have any reproducer for this crash yet.
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+ccc15f...@syzkaller.appspotmail.com
======================================================
WARNING: possible circular locking dependency detected
4.19.125-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.3/1887 is trying to acquire lock:
00000000c1f2fa45 ((wq_completion)"dio/%s"sb->s_id){+.+.}, at: flush_workqueue+0xf7/0x1440 kernel/workqueue.c:2660
FAT-fs (loop2): error, invalid access to FAT (entry 0x00000020)
but task is already holding lock:
00000000891b42bf (&sb->s_type->i_mutex_key#9){++++}, at: inode_trylock include/linux/fs.h:768 [inline]
00000000891b42bf (&sb->s_type->i_mutex_key#9){++++}, at: ext4_file_write_iter+0x21f/0xf60 fs/ext4/file.c:238
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (&sb->s_type->i_mutex_key#9){++++}:
inode_lock include/linux/fs.h:748 [inline]
__generic_file_fsync+0xb0/0x1f0 fs/libfs.c:987
ext4_sync_file+0xa28/0x1430 fs/ext4/fsync.c:120
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
FAT-fs (loop2): Filesystem has been set read-only
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
FAT-fs (loop2): error, invalid access to FAT (entry 0x00000020)
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
sb_init_dio_done_wq+0x72/0x90 fs/direct-io.c:634
do_blockdev_direct_IO fs/direct-io.c:1284 [inline]
__blockdev_direct_IO+0x6445/0xfe24 fs/direct-io.c:1418
ext4_direct_IO_write fs/ext4/inode.c:3769 [inline]
ext4_direct_IO+0xa8b/0x1ab0 fs/ext4/inode.c:3902
generic_file_direct_write+0x207/0x490 mm/filemap.c:3065
__generic_file_write_iter+0x2d4/0x610 mm/filemap.c:3244
ext4_file_write_iter+0x2fe/0xf60 fs/ext4/file.c:272
FAT-fs (loop5): error, invalid access to FAT (entry 0x00000020)
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
attempt to access beyond end of device
loop2: rw=34817, want=157, limit=116
other info that might help us debug this:
FAT-fs (loop5): Filesystem has been set read-only
Chain exists of:
(wq_completion)"dio/%s"sb->s_id --> (work_completion)(&dio->complete_work) --> &sb->s_type->i_mutex_key#9
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&sb->s_type->i_mutex_key#9);
lock((work_completion)(&dio->complete_work));
lock(&sb->s_type->i_mutex_key#9);
FAT-fs (loop5): error, invalid access to FAT (entry 0x00000020)
lock((wq_completion)"dio/%s"sb->s_id);
*** DEADLOCK ***
1 lock held by syz-executor.3/1887:
#0: 00000000891b42bf (&sb->s_type->i_mutex_key#9){++++}, at: inode_trylock include/linux/fs.h:768 [inline]
#0: 00000000891b42bf (&sb->s_type->i_mutex_key#9){++++}, at: ext4_file_write_iter+0x21f/0xf60 fs/ext4/file.c:238
stack backtrace:
CPU: 0 PID: 1887 Comm: syz-executor.3 Not tainted 4.19.125-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
attempt to access beyond end of device
drain_workqueue+0x1a7/0x460 kernel/workqueue.c:2828
destroy_workqueue+0x75/0x6f0 kernel/workqueue.c:4172
loop5: rw=34817, want=157, limit=116
sb_init_dio_done_wq+0x72/0x90 fs/direct-io.c:634
do_blockdev_direct_IO fs/direct-io.c:1284 [inline]
__blockdev_direct_IO+0x6445/0xfe24 fs/direct-io.c:1418
FAT-fs (loop4): error, invalid access to FAT (entry 0x00000020)
ext4_direct_IO_write fs/ext4/inode.c:3769 [inline]
ext4_direct_IO+0xa8b/0x1ab0 fs/ext4/inode.c:3902
generic_file_direct_write+0x207/0x490 mm/filemap.c:3065
FAT-fs (loop4): Filesystem has been set read-only
__generic_file_write_iter+0x2d4/0x610 mm/filemap.c:3244
ext4_file_write_iter+0x2fe/0xf60 fs/ext4/file.c:272
call_write_iter include/linux/fs.h:1821 [inline]
aio_write+0x346/0x530 fs/aio.c:1573
FAT-fs (loop4): error, invalid access to FAT (entry 0x00000020)
__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:00007f2ae55ebc78 EFLAGS: 00000246 ORIG_RAX: 00000000000000d1
RAX: ffffffffffffffda RBX: 00000000004e0d40 RCX: 000000000045ca69
RDX: 0000000020000540 RSI: 0000000000000006 RDI: 00007f2ae55a8000
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000001fb R14: 00000000004c4486 R15: 00007f2ae55ec6d4
FAT-fs (loop2): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop2): Filesystem has been set read-only
FAT-fs (loop2): error, invalid access to FAT (entry 0x00000020)
attempt to access beyond end of device
loop2: rw=34817, want=157, limit=116
9pnet: p9_errstr2errno: server reported unknown error �ȢV�
Can not set IPV6_FL_F_REFLECT if flowlabel_consistency sysctl is enable
Can not set IPV6_FL_F_REFLECT if flowlabel_consistency sysctl is enable
Can not set IPV6_FL_F_REFLECT if flowlabel_consistency sysctl is enable
Can not set IPV6_FL_F_REFLECT if flowlabel_consistency sysctl is enable
9pnet: p9_errstr2errno: server reported unknown error �ȢV�
---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.
syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
syzbot
Sep 30, 2020, 8:41:09 PM9/30/20
to syzkaller...@googlegroups.com
Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.
Crashes did not happen for a while, no reproducer and no activity.
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