possible deadlock in ext4_file_write_iter
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syzbot
Mar 25, 2020, 8:13:19 AM3/25/20
to syzkaller...@googlegroups.com
Hello,
syzbot found the following crash on:
HEAD commit: 01364dad Linux 4.14.174
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=155b2a03e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=664dd71881ab2b2d
dashboard link: https://syzkaller.appspot.com/bug?extid=0456fbb3a6f333f981df
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+0456fb...@syzkaller.appspotmail.com
======================================================
WARNING: possible circular locking dependency detected
4.14.174-syzkaller #0 Not tainted
------------------------------------------------------
ieee80211 phy2: hwaddr 02:00:00:00:02:00 registered
syz-executor.4/25997 is trying to acquire lock:
("dio/%s"sb->s_id){+.+.}, at: [<ffffffff813ae9ba>] flush_workqueue+0xda/0x13f0 kernel/workqueue.c:2621
but task is already holding lock:
(&sb->s_type->i_mutex_key#9){+.+.}, at: [<ffffffff81bbc625>] inode_trylock include/linux/fs.h:738 [inline]
(&sb->s_type->i_mutex_key#9){+.+.}, at: [<ffffffff81bbc625>] ext4_file_write_iter+0x1d5/0xdc0 fs/ext4/file.c:236
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (&sb->s_type->i_mutex_key#9){+.+.}:
down_write+0x34/0x90 kernel/locking/rwsem.c:54
inode_lock include/linux/fs.h:718 [inline]
__generic_file_fsync+0x9e/0x190 fs/libfs.c:985
ext4_sync_file+0x757/0x12c0 fs/ext4/fsync.c:120
vfs_fsync_range+0x103/0x250 fs/sync.c:196
generic_write_sync include/linux/fs.h:2677 [inline]
dio_complete+0x37d/0x840 fs/direct-io.c:330
process_one_work+0x813/0x1540 kernel/workqueue.c:2116
worker_thread+0x5d1/0x1070 kernel/workqueue.c:2250
kthread+0x30d/0x420 kernel/kthread.c:232
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
-> #1 ((&dio->complete_work)){+.+.}:
process_one_work+0x7b5/0x1540 kernel/workqueue.c:2092
worker_thread+0x5d1/0x1070 kernel/workqueue.c:2250
kthread+0x30d/0x420 kernel/kthread.c:232
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
-> #0 ("dio/%s"sb->s_id){+.+.}:
lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3994
flush_workqueue+0x109/0x13f0 kernel/workqueue.c:2624
drain_workqueue+0x177/0x3e0 kernel/workqueue.c:2789
destroy_workqueue+0x71/0x660 kernel/workqueue.c:4102
sb_init_dio_done_wq+0x61/0x80 fs/direct-io.c:635
do_blockdev_direct_IO+0x3842/0x9120 fs/direct-io.c:1286
ext4_direct_IO_write fs/ext4/inode.c:3712 [inline]
ext4_direct_IO+0x7cf/0x1980 fs/ext4/inode.c:3848
generic_file_direct_write+0x1df/0x420 mm/filemap.c:2950
__generic_file_write_iter+0x2a5/0x590 mm/filemap.c:3129
ext4_file_write_iter+0x808/0xdc0 fs/ext4/file.c:270
call_write_iter include/linux/fs.h:1777 [inline]
aio_write+0x2c7/0x4f0 fs/aio.c:1553
io_submit_one fs/aio.c:1641 [inline]
do_io_submit+0x996/0x13f0 fs/aio.c:1709
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
other info that might help us debug this:
Chain exists of:
"dio/%s"sb->s_id --> (&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((&dio->complete_work));
lock(&sb->s_type->i_mutex_key#9);
lock("dio/%s"sb->s_id);
*** DEADLOCK ***
2 locks held by syz-executor.4/25997:
#0: (sb_writers#4){.+.+}, at: [<ffffffff819c46b6>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff819c46b6>] aio_write+0x426/0x4f0 fs/aio.c:1552
#1: (&sb->s_type->i_mutex_key#9){+.+.}, at: [<ffffffff81bbc625>] inode_trylock include/linux/fs.h:738 [inline]
#1: (&sb->s_type->i_mutex_key#9){+.+.}, at: [<ffffffff81bbc625>] ext4_file_write_iter+0x1d5/0xdc0 fs/ext4/file.c:236
stack backtrace:
CPU: 1 PID: 25997 Comm: syz-executor.4 Not tainted 4.14.174-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0x13e/0x194 lib/dump_stack.c:58
print_circular_bug.isra.0.cold+0x1c4/0x282 kernel/locking/lockdep.c:1258
check_prev_add kernel/locking/lockdep.c:1901 [inline]
check_prevs_add kernel/locking/lockdep.c:2018 [inline]
validate_chain kernel/locking/lockdep.c:2460 [inline]
__lock_acquire+0x2cb3/0x4620 kernel/locking/lockdep.c:3487
lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3994
flush_workqueue+0x109/0x13f0 kernel/workqueue.c:2624
drain_workqueue+0x177/0x3e0 kernel/workqueue.c:2789
destroy_workqueue+0x71/0x660 kernel/workqueue.c:4102
sb_init_dio_done_wq+0x61/0x80 fs/direct-io.c:635
do_blockdev_direct_IO+0x3842/0x9120 fs/direct-io.c:1286
ext4_direct_IO_write fs/ext4/inode.c:3712 [inline]
ext4_direct_IO+0x7cf/0x1980 fs/ext4/inode.c:3848
generic_file_direct_write+0x1df/0x420 mm/filemap.c:2950
__generic_file_write_iter+0x2a5/0x590 mm/filemap.c:3129
ext4_file_write_iter+0x808/0xdc0 fs/ext4/file.c:270
call_write_iter include/linux/fs.h:1777 [inline]
aio_write+0x2c7/0x4f0 fs/aio.c:1553
io_submit_one fs/aio.c:1641 [inline]
do_io_submit+0x996/0x13f0 fs/aio.c:1709
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45c849
RSP: 002b:00007fa5fdc59c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000d1
RAX: ffffffffffffffda RBX: 00007fa5fdc5a6d4 RCX: 000000000045c849
RDX: 0000000020000540 RSI: 0000000000000006 RDI: 00007fa5fdc16000
RBP: 000000000076bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000001f9 R14: 00000000004c422b R15: 000000000076bf0c
ieee80211 phy3: Selected rate control algorithm 'minstrel_ht'
ieee80211 phy3: hwaddr 02:00:00:00:03:00 registered
ieee80211 phy4: Selected rate control algorithm 'minstrel_ht'
ieee80211 phy4: hwaddr 02:00:00:00:04:00 registered
ieee80211 phy5: Selected rate control algorithm 'minstrel_ht'
ieee80211 phy5: hwaddr 02:00:00:00:05:00 registered
ieee80211 phy6: Selected rate control algorithm 'minstrel_ht'
ieee80211 phy6: hwaddr 02:00:00:00:06:00 registered
ieee80211 phy7: Selected rate control algorithm 'minstrel_ht'
ieee80211 phy7: hwaddr 02:00:00:00:07:00 registered
ieee80211 phy8: Selected rate control algorithm 'minstrel_ht'
ieee80211 phy8: hwaddr 02:00:00:00:08:00 registered
ieee80211 phy9: Selected rate control algorithm 'minstrel_ht'
ieee80211 phy9: hwaddr 02:00:00:00:09:00 registered
ieee80211 phy10: Selected rate control algorithm 'minstrel_ht'
ieee80211 phy10: hwaddr 02:00:00:00:0a:00 registered
ieee80211 phy11: Selected rate control algorithm 'minstrel_ht'
ieee80211 phy11: hwaddr 02:00:00:00:0b:00 registered
ieee80211 phy12: Selected rate control algorithm 'minstrel_ht'
ieee80211 phy12: hwaddr 02:00:00:00:0c:00 registered
ieee80211 phy13: Selected rate control algorithm 'minstrel_ht'
ieee80211 phy13: hwaddr 02:00:00:00:0d:00 registered
ieee80211 phy14: Selected rate control algorithm 'minstrel_ht'
ieee80211 phy14: hwaddr 02:00:00:00:0e:00 registered
ieee80211 phy15: Selected rate control algorithm 'minstrel_ht'
ieee80211 phy15: hwaddr 02:00:00:00:0f:00 registered
IPVS: length: 4096 != 24
IPVS: length: 4096 != 24
IPVS: length: 4096 != 24
IPVS: length: 4096 != 24
IPVS: length: 4096 != 24
---
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: 01364dad Linux 4.14.174
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=155b2a03e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=664dd71881ab2b2d
dashboard link: https://syzkaller.appspot.com/bug?extid=0456fbb3a6f333f981df
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+0456fb...@syzkaller.appspotmail.com
======================================================
WARNING: possible circular locking dependency detected
4.14.174-syzkaller #0 Not tainted
------------------------------------------------------
ieee80211 phy2: hwaddr 02:00:00:00:02:00 registered
syz-executor.4/25997 is trying to acquire lock:
("dio/%s"sb->s_id){+.+.}, at: [<ffffffff813ae9ba>] flush_workqueue+0xda/0x13f0 kernel/workqueue.c:2621
but task is already holding lock:
(&sb->s_type->i_mutex_key#9){+.+.}, at: [<ffffffff81bbc625>] inode_trylock include/linux/fs.h:738 [inline]
(&sb->s_type->i_mutex_key#9){+.+.}, at: [<ffffffff81bbc625>] ext4_file_write_iter+0x1d5/0xdc0 fs/ext4/file.c:236
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (&sb->s_type->i_mutex_key#9){+.+.}:
down_write+0x34/0x90 kernel/locking/rwsem.c:54
inode_lock include/linux/fs.h:718 [inline]
__generic_file_fsync+0x9e/0x190 fs/libfs.c:985
ext4_sync_file+0x757/0x12c0 fs/ext4/fsync.c:120
vfs_fsync_range+0x103/0x250 fs/sync.c:196
generic_write_sync include/linux/fs.h:2677 [inline]
dio_complete+0x37d/0x840 fs/direct-io.c:330
process_one_work+0x813/0x1540 kernel/workqueue.c:2116
worker_thread+0x5d1/0x1070 kernel/workqueue.c:2250
kthread+0x30d/0x420 kernel/kthread.c:232
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
-> #1 ((&dio->complete_work)){+.+.}:
process_one_work+0x7b5/0x1540 kernel/workqueue.c:2092
worker_thread+0x5d1/0x1070 kernel/workqueue.c:2250
kthread+0x30d/0x420 kernel/kthread.c:232
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
-> #0 ("dio/%s"sb->s_id){+.+.}:
lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3994
flush_workqueue+0x109/0x13f0 kernel/workqueue.c:2624
drain_workqueue+0x177/0x3e0 kernel/workqueue.c:2789
destroy_workqueue+0x71/0x660 kernel/workqueue.c:4102
sb_init_dio_done_wq+0x61/0x80 fs/direct-io.c:635
do_blockdev_direct_IO+0x3842/0x9120 fs/direct-io.c:1286
ext4_direct_IO_write fs/ext4/inode.c:3712 [inline]
ext4_direct_IO+0x7cf/0x1980 fs/ext4/inode.c:3848
generic_file_direct_write+0x1df/0x420 mm/filemap.c:2950
__generic_file_write_iter+0x2a5/0x590 mm/filemap.c:3129
ext4_file_write_iter+0x808/0xdc0 fs/ext4/file.c:270
call_write_iter include/linux/fs.h:1777 [inline]
aio_write+0x2c7/0x4f0 fs/aio.c:1553
io_submit_one fs/aio.c:1641 [inline]
do_io_submit+0x996/0x13f0 fs/aio.c:1709
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
other info that might help us debug this:
Chain exists of:
"dio/%s"sb->s_id --> (&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((&dio->complete_work));
lock(&sb->s_type->i_mutex_key#9);
lock("dio/%s"sb->s_id);
*** DEADLOCK ***
2 locks held by syz-executor.4/25997:
#0: (sb_writers#4){.+.+}, at: [<ffffffff819c46b6>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff819c46b6>] aio_write+0x426/0x4f0 fs/aio.c:1552
#1: (&sb->s_type->i_mutex_key#9){+.+.}, at: [<ffffffff81bbc625>] inode_trylock include/linux/fs.h:738 [inline]
#1: (&sb->s_type->i_mutex_key#9){+.+.}, at: [<ffffffff81bbc625>] ext4_file_write_iter+0x1d5/0xdc0 fs/ext4/file.c:236
stack backtrace:
CPU: 1 PID: 25997 Comm: syz-executor.4 Not tainted 4.14.174-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0x13e/0x194 lib/dump_stack.c:58
print_circular_bug.isra.0.cold+0x1c4/0x282 kernel/locking/lockdep.c:1258
check_prev_add kernel/locking/lockdep.c:1901 [inline]
check_prevs_add kernel/locking/lockdep.c:2018 [inline]
validate_chain kernel/locking/lockdep.c:2460 [inline]
__lock_acquire+0x2cb3/0x4620 kernel/locking/lockdep.c:3487
lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3994
flush_workqueue+0x109/0x13f0 kernel/workqueue.c:2624
drain_workqueue+0x177/0x3e0 kernel/workqueue.c:2789
destroy_workqueue+0x71/0x660 kernel/workqueue.c:4102
sb_init_dio_done_wq+0x61/0x80 fs/direct-io.c:635
do_blockdev_direct_IO+0x3842/0x9120 fs/direct-io.c:1286
ext4_direct_IO_write fs/ext4/inode.c:3712 [inline]
ext4_direct_IO+0x7cf/0x1980 fs/ext4/inode.c:3848
generic_file_direct_write+0x1df/0x420 mm/filemap.c:2950
__generic_file_write_iter+0x2a5/0x590 mm/filemap.c:3129
ext4_file_write_iter+0x808/0xdc0 fs/ext4/file.c:270
call_write_iter include/linux/fs.h:1777 [inline]
aio_write+0x2c7/0x4f0 fs/aio.c:1553
io_submit_one fs/aio.c:1641 [inline]
do_io_submit+0x996/0x13f0 fs/aio.c:1709
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45c849
RSP: 002b:00007fa5fdc59c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000d1
RAX: ffffffffffffffda RBX: 00007fa5fdc5a6d4 RCX: 000000000045c849
RDX: 0000000020000540 RSI: 0000000000000006 RDI: 00007fa5fdc16000
RBP: 000000000076bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000001f9 R14: 00000000004c422b R15: 000000000076bf0c
ieee80211 phy3: Selected rate control algorithm 'minstrel_ht'
ieee80211 phy3: hwaddr 02:00:00:00:03:00 registered
ieee80211 phy4: Selected rate control algorithm 'minstrel_ht'
ieee80211 phy4: hwaddr 02:00:00:00:04:00 registered
ieee80211 phy5: Selected rate control algorithm 'minstrel_ht'
ieee80211 phy5: hwaddr 02:00:00:00:05:00 registered
ieee80211 phy6: Selected rate control algorithm 'minstrel_ht'
ieee80211 phy6: hwaddr 02:00:00:00:06:00 registered
ieee80211 phy7: Selected rate control algorithm 'minstrel_ht'
ieee80211 phy7: hwaddr 02:00:00:00:07:00 registered
ieee80211 phy8: Selected rate control algorithm 'minstrel_ht'
ieee80211 phy8: hwaddr 02:00:00:00:08:00 registered
ieee80211 phy9: Selected rate control algorithm 'minstrel_ht'
ieee80211 phy9: hwaddr 02:00:00:00:09:00 registered
ieee80211 phy10: Selected rate control algorithm 'minstrel_ht'
ieee80211 phy10: hwaddr 02:00:00:00:0a:00 registered
ieee80211 phy11: Selected rate control algorithm 'minstrel_ht'
ieee80211 phy11: hwaddr 02:00:00:00:0b:00 registered
ieee80211 phy12: Selected rate control algorithm 'minstrel_ht'
ieee80211 phy12: hwaddr 02:00:00:00:0c:00 registered
ieee80211 phy13: Selected rate control algorithm 'minstrel_ht'
ieee80211 phy13: hwaddr 02:00:00:00:0d:00 registered
ieee80211 phy14: Selected rate control algorithm 'minstrel_ht'
ieee80211 phy14: hwaddr 02:00:00:00:0e:00 registered
ieee80211 phy15: Selected rate control algorithm 'minstrel_ht'
ieee80211 phy15: hwaddr 02:00:00:00:0f:00 registered
IPVS: length: 4096 != 24
IPVS: length: 4096 != 24
IPVS: length: 4096 != 24
IPVS: length: 4096 != 24
IPVS: length: 4096 != 24
---
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 14, 2020, 2:49:15 AM9/14/20
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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