[syzbot] possible deadlock in jbd2_journal_lock_updates

syzbot
2022-08-08T07:35:04Z

Hello,

syzbot found the following issue on:

HEAD commit: ca688bff68bc Add linux-next specific files for 20220808
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=1228affe080000
kernel config: https://syzkaller.appspot.com/x/.config?x=4c20e006003cdecb
dashboard link: https://syzkaller.appspot.com/bug?extid=79e6bbabf3ce17357969
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+79e6bbabf3ce17357969@syzkaller.appspotmail.com

======================================================
WARNING: possible circular locking dependency detected
5.19.0-next-20220808-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.2/10446 is trying to acquire lock:
ffff88807feb0170 (&journal->j_barrier){+.+.}-{3:3}, at: jbd2_journal_lock_updates+0x15e/0x310 fs/jbd2/transaction.c:904

but task is already holding lock:
ffff88807ff5ebd8 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_change_inode_journal_flag+0x178/0x530 fs/ext4/inode.c:6013

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #3 (&sbi->s_writepages_rwsem){++++}-{0:0}:
percpu_down_write+0x4d/0x440 kernel/locking/percpu-rwsem.c:221
ext4_ind_migrate+0x237/0x840 fs/ext4/migrate.c:624
ext4_ioctl_setflags fs/ext4/ioctl.c:694 [inline]
ext4_fileattr_set+0x14b8/0x1930 fs/ext4/ioctl.c:1001
vfs_fileattr_set+0x7f5/0xbe0 fs/ioctl.c:696
ioctl_fssetxattr fs/ioctl.c:758 [inline]
do_vfs_ioctl+0xe62/0x15c0 fs/ioctl.c:845
__do_sys_ioctl fs/ioctl.c:868 [inline]
__se_sys_ioctl fs/ioctl.c:856 [inline]
__x64_sys_ioctl+0x108/0x200 fs/ioctl.c:856
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #2 (&sb->s_type->i_mutex_key#8){++++}-{3:3}:
down_read+0x98/0x450 kernel/locking/rwsem.c:1499
inode_lock_shared include/linux/fs.h:771 [inline]
ext4_bmap+0x4e/0x460 fs/ext4/inode.c:3157
bmap+0xaa/0x120 fs/inode.c:1799
jbd2_journal_bmap+0xa8/0x180 fs/jbd2/journal.c:971
__jbd2_journal_erase fs/jbd2/journal.c:1784 [inline]
jbd2_journal_flush+0x84f/0xc00 fs/jbd2/journal.c:2490
ext4_ioctl_checkpoint fs/ext4/ioctl.c:1082 [inline]
__ext4_ioctl+0x28fd/0x4ab0 fs/ext4/ioctl.c:1586
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl fs/ioctl.c:856 [inline]
__x64_sys_ioctl+0x193/0x200 fs/ioctl.c:856
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #1 (&journal->j_checkpoint_mutex){+.+.}-{3:3}:
__mutex_lock_common kernel/locking/mutex.c:603 [inline]
mutex_lock_io_nested+0x13f/0x1190 kernel/locking/mutex.c:833
jbd2_journal_flush+0x19a/0xc00 fs/jbd2/journal.c:2462
ext4_ioctl_checkpoint fs/ext4/ioctl.c:1082 [inline]
__ext4_ioctl+0x28fd/0x4ab0 fs/ext4/ioctl.c:1586
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl fs/ioctl.c:856 [inline]
__x64_sys_ioctl+0x193/0x200 fs/ioctl.c:856
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #0 (&journal->j_barrier){+.+.}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3095 [inline]
check_prevs_add kernel/locking/lockdep.c:3214 [inline]
validate_chain kernel/locking/lockdep.c:3829 [inline]
__lock_acquire+0x2a43/0x56d0 kernel/locking/lockdep.c:5053
lock_acquire kernel/locking/lockdep.c:5666 [inline]
lock_acquire+0x1ab/0x570 kernel/locking/lockdep.c:5631
__mutex_lock_common kernel/locking/mutex.c:603 [inline]
__mutex_lock+0x12f/0x1350 kernel/locking/mutex.c:747
jbd2_journal_lock_updates+0x15e/0x310 fs/jbd2/transaction.c:904
ext4_change_inode_journal_flag+0x180/0x530 fs/ext4/inode.c:6014
ext4_ioctl_setflags fs/ext4/ioctl.c:685 [inline]
ext4_fileattr_set+0xddf/0x1930 fs/ext4/ioctl.c:1001
vfs_fileattr_set+0x7f5/0xbe0 fs/ioctl.c:696
ioctl_fssetxattr fs/ioctl.c:758 [inline]
do_vfs_ioctl+0xe62/0x15c0 fs/ioctl.c:845
__do_sys_ioctl fs/ioctl.c:868 [inline]
__se_sys_ioctl fs/ioctl.c:856 [inline]
__x64_sys_ioctl+0x108/0x200 fs/ioctl.c:856
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

other info that might help us debug this:

Chain exists of:
&journal->j_barrier --> &sb->s_type->i_mutex_key#8 --> &sbi->s_writepages_rwsem

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&sbi->s_writepages_rwsem);
lock(&sb->s_type->i_mutex_key#8);
lock(&sbi->s_writepages_rwsem);
lock(&journal->j_barrier);

*** DEADLOCK ***

4 locks held by syz-executor.2/10446:
#0: ffff88807ff5c460 (sb_writers#4){.+.+}-{0:0}, at: ioctl_setflags fs/ioctl.c:725 [inline]
#0: ffff88807ff5c460 (sb_writers#4){.+.+}-{0:0}, at: do_vfs_ioctl+0xe27/0x15c0 fs/ioctl.c:839
#1: ffff88802b44de48 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: inode_lock include/linux/fs.h:761 [inline]
#1: ffff88802b44de48 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: vfs_fileattr_set+0x148/0xbe0 fs/ioctl.c:681
#2: ffff88802b44dfe8 (mapping.invalidate_lock){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:806 [inline]
#2: ffff88802b44dfe8 (mapping.invalidate_lock){++++}-{3:3}, at: ext4_change_inode_journal_flag+0x11f/0x530 fs/ext4/inode.c:6005
#3: ffff88807ff5ebd8 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_change_inode_journal_flag+0x178/0x530 fs/ext4/inode.c:6013

stack backtrace:
CPU: 0 PID: 10446 Comm: syz-executor.2 Not tainted 5.19.0-next-20220808-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2175
check_prev_add kernel/locking/lockdep.c:3095 [inline]
check_prevs_add kernel/locking/lockdep.c:3214 [inline]
validate_chain kernel/locking/lockdep.c:3829 [inline]
__lock_acquire+0x2a43/0x56d0 kernel/locking/lockdep.c:5053
lock_acquire kernel/locking/lockdep.c:5666 [inline]
lock_acquire+0x1ab/0x570 kernel/locking/lockdep.c:5631
__mutex_lock_common kernel/locking/mutex.c:603 [inline]
__mutex_lock+0x12f/0x1350 kernel/locking/mutex.c:747
jbd2_journal_lock_updates+0x15e/0x310 fs/jbd2/transaction.c:904
ext4_change_inode_journal_flag+0x180/0x530 fs/ext4/inode.c:6014
ext4_ioctl_setflags fs/ext4/ioctl.c:685 [inline]
ext4_fileattr_set+0xddf/0x1930 fs/ext4/ioctl.c:1001
vfs_fileattr_set+0x7f5/0xbe0 fs/ioctl.c:696
ioctl_fssetxattr fs/ioctl.c:758 [inline]
do_vfs_ioctl+0xe62/0x15c0 fs/ioctl.c:845
__do_sys_ioctl fs/ioctl.c:868 [inline]
__se_sys_ioctl fs/ioctl.c:856 [inline]
__x64_sys_ioctl+0x108/0x200 fs/ioctl.c:856
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f2195489279
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f219651b168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f219559bf80 RCX: 00007f2195489279
RDX: 0000000020000380 RSI: 0000000040086602 RDI: 0000000000000003
RBP: 00007f21954e3189 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffd08022a2f R14: 00007f219651b300 R15: 0000000000022000
</TASK>

---
This report 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 syzkaller@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.