EXT4-fs (loop8): external journal has bad superblock
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.8.708/10445 is trying to acquire lock:
ffff8880233e54c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0xff/0x760 block/bdev.c:944
but task is already holding lock:
ffff88807edae0e0 (&type->s_umount_key#31){++++}-{3:3}
, at: ext4_get_journal_blkdev fs/ext4/super.c:5882 [inline]
, at: ext4_open_dev_journal fs/ext4/super.c:5954 [inline]
, at: ext4_load_journal fs/ext4/super.c:6017 [inline]
, at: ext4_load_and_init_journal+0x280/0x2100 fs/ext4/super.c:4918
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (&type->s_umount_key#31){++++}-{3:3}:
down_read+0x46/0x2e0 kernel/locking/rwsem.c:1520
__super_lock fs/super.c:58 [inline]
super_lock+0x167/0x360 fs/super.c:117
super_lock_shared fs/super.c:146 [inline]
super_lock_shared_active fs/super.c:1442 [inline]
fs_bdev_mark_dead+0xad/0x1f0 fs/super.c:1458
bdev_mark_dead+0x83/0x1a0 block/bdev.c:1030
disk_force_media_change+0x132/0x1b0 block/disk-events.c:302
__loop_clr_fd+0x396/0x660 drivers/block/loop.c:1170
loop_clr_fd drivers/block/loop.c:1253 [inline]
lo_ioctl+0x11e8/0x19f0 drivers/block/loop.c:1578
blkdev_ioctl+0x58b/0x6f0 block/ioctl.c:639
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:871 [inline]
__se_sys_ioctl+0xfd/0x170 fs/ioctl.c:857
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
-> #1 (&bdev->bd_holder_lock){+.+.}-{3:3}:
__mutex_lock_common kernel/locking/mutex.c:603 [inline]
__mutex_lock+0x129/0xcc0 kernel/locking/mutex.c:747
bdev_mark_dead+0x31/0x1a0 block/bdev.c:1028
disk_force_media_change+0x132/0x1b0 block/disk-events.c:302
__loop_clr_fd+0x396/0x660 drivers/block/loop.c:1170
blkdev_put+0x5bd/0x760 block/bdev.c:-1
bdev_release+0x57/0x70 block/bdev.c:968
ext4_kill_sb+0x68/0xa0 fs/ext4/super.c:7391
deactivate_locked_super+0x97/0x100 fs/super.c:481
cleanup_mnt+0x429/0x4c0 fs/namespace.c:1259
task_work_run+0x1ce/0x250 kernel/task_work.c:239
resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177
exit_to_user_mode_prepare+0xf6/0x180 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:87
entry_SYSCALL_64_after_hwframe+0x68/0xd2
-> #0 (&disk->open_mutex){+.+.}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3134 [inline]
check_prevs_add kernel/locking/lockdep.c:3253 [inline]
validate_chain kernel/locking/lockdep.c:3869 [inline]
__lock_acquire+0x2ddb/0x7c80 kernel/locking/lockdep.c:5137
lock_acquire+0x197/0x410 kernel/locking/lockdep.c:5754
__mutex_lock_common kernel/locking/mutex.c:603 [inline]
__mutex_lock+0x129/0xcc0 kernel/locking/mutex.c:747
blkdev_put+0xff/0x760 block/bdev.c:944
ext4_get_journal_blkdev fs/ext4/super.c:5941 [inline]
ext4_open_dev_journal fs/ext4/super.c:5954 [inline]
ext4_load_journal fs/ext4/super.c:6017 [inline]
ext4_load_and_init_journal+0xcef/0x2100 fs/ext4/super.c:4918
__ext4_fill_super fs/ext4/super.c:5391 [inline]
ext4_fill_super+0x419e/0x66c0 fs/ext4/super.c:5724
get_tree_bdev+0x3e4/0x510 fs/super.c:1591
vfs_get_tree+0x8c/0x280 fs/super.c:1764
do_new_mount+0x24b/0xa40 fs/namespace.c:3386
do_mount fs/namespace.c:3726 [inline]
__do_sys_mount fs/namespace.c:3935 [inline]
__se_sys_mount+0x2da/0x3c0 fs/namespace.c:3912
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
other info that might help us debug this:
Chain exists of:
&disk->open_mutex --> &bdev->bd_holder_lock --> &type->s_umount_key#31
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&type->s_umount_key#31);
lock(&bdev->bd_holder_lock);
lock(&type->s_umount_key#31);
lock(&disk->open_mutex);
*** DEADLOCK ***
1 lock held by syz.8.708/10445:
#0: ffff88807edae0e0 (&type->s_umount_key#31){++++}-{3:3}, at: ext4_get_journal_blkdev fs/ext4/super.c:5882 [inline]
#0: ffff88807edae0e0 (&type->s_umount_key#31){++++}-{3:3}, at: ext4_open_dev_journal fs/ext4/super.c:5954 [inline]
#0: ffff88807edae0e0 (&type->s_umount_key#31){++++}-{3:3}, at: ext4_load_journal fs/ext4/super.c:6017 [inline]
#0: ffff88807edae0e0 (&type->s_umount_key#31){++++}-{3:3}, at: ext4_load_and_init_journal+0x280/0x2100 fs/ext4/super.c:4918
stack backtrace:
CPU: 0 PID: 10445 Comm: syz.8.708 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
<TASK>
dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106
check_noncircular+0x2bd/0x3c0 kernel/locking/lockdep.c:2187
check_prev_add kernel/locking/lockdep.c:3134 [inline]
check_prevs_add kernel/locking/lockdep.c:3253 [inline]
validate_chain kernel/locking/lockdep.c:3869 [inline]
__lock_acquire+0x2ddb/0x7c80 kernel/locking/lockdep.c:5137
lock_acquire+0x197/0x410 kernel/locking/lockdep.c:5754
__mutex_lock_common kernel/locking/mutex.c:603 [inline]
__mutex_lock+0x129/0xcc0 kernel/locking/mutex.c:747
blkdev_put+0xff/0x760 block/bdev.c:944
ext4_get_journal_blkdev fs/ext4/super.c:5941 [inline]
ext4_open_dev_journal fs/ext4/super.c:5954 [inline]
ext4_load_journal fs/ext4/super.c:6017 [inline]
ext4_load_and_init_journal+0xcef/0x2100 fs/ext4/super.c:4918
__ext4_fill_super fs/ext4/super.c:5391 [inline]
ext4_fill_super+0x419e/0x66c0 fs/ext4/super.c:5724
get_tree_bdev+0x3e4/0x510 fs/super.c:1591
vfs_get_tree+0x8c/0x280 fs/super.c:1764
do_new_mount+0x24b/0xa40 fs/namespace.c:3386
do_mount fs/namespace.c:3726 [inline]
__do_sys_mount fs/namespace.c:3935 [inline]
__se_sys_mount+0x2da/0x3c0 fs/namespace.c:3912
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fdef8790eea
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fdef96c1e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fdef96c1ef0 RCX: 00007fdef8790eea
RDX: 0000200000000080 RSI: 0000200000000480 RDI: 00007fdef96c1eb0
RBP: 0000200000000080 R08: 00007fdef96c1ef0 R09: 0000000001008002
R10: 0000000001008002 R11: 0000000000000246 R12: 0000200000000480
R13: 00007fdef96c1eb0 R14: 0000000000000477 R15: 00002000000001c0
</TASK>