EXT4-fs error (device loop2) in ext4_mb_clear_bb:6655: Corrupt filesystem EXT4-fs (loop2): 1 truncate cleaned up EXT4-fs (loop2): mounted filesystem 00000000-0000-0000-0000-000000000000 ro without journal. Quota mode: writeback. ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.2.5112/24143 is trying to acquire lock: ffff88807ace00e0 (&type->s_umount_key#31){++++}-{3:3}, at: __super_lock fs/super.c:58 [inline] ffff88807ace00e0 (&type->s_umount_key#31){++++}-{3:3}, at: super_lock+0x17f/0x3a0 fs/super.c:117 but task is already holding lock: ffff8880200bdd08 (&bdev->bd_holder_lock){+.+.}-{3:3}, at: blkdev_flushbuf block/ioctl.c:379 [inline] ffff8880200bdd08 (&bdev->bd_holder_lock){+.+.}-{3:3}, at: blkdev_common_ioctl+0x835/0x2570 block/ioctl.c:511 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&bdev->bd_holder_lock){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x136/0xcc0 kernel/locking/mutex.c:747 bdev_mark_dead+0x31/0x1a0 block/bdev.c:1028 disk_force_media_change+0x14e/0x1d0 block/disk-events.c:302 __loop_clr_fd+0x396/0x660 drivers/block/loop.c:1170 blkdev_put+0x5bd/0x760 block/bdev.c:-1 blkdev_release+0x84/0x90 block/fops.c:604 __fput+0x234/0x970 fs/file_table.c:384 __do_sys_close fs/open.c:1573 [inline] __se_sys_close+0x15f/0x220 fs/open.c:1558 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 -> #1 (&disk->open_mutex){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x136/0xcc0 kernel/locking/mutex.c:747 blkdev_put+0xff/0x760 block/bdev.c:944 ext4_get_journal_blkdev fs/ext4/super.c:5961 [inline] ext4_open_dev_journal fs/ext4/super.c:5974 [inline] ext4_load_journal fs/ext4/super.c:6037 [inline] ext4_load_and_init_journal+0xcef/0x2100 fs/ext4/super.c:4923 __ext4_fill_super fs/ext4/super.c:5411 [inline] ext4_fill_super+0x430a/0x67b0 fs/ext4/super.c:5744 get_tree_bdev+0x3f3/0x520 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+0x2e7/0x3d0 fs/namespace.c:3912 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 -> #0 (&type->s_umount_key#31){++++}-{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+0x2df1/0x7d40 kernel/locking/lockdep.c:5137 lock_acquire+0x19e/0x420 kernel/locking/lockdep.c:5754 down_read+0x46/0x2e0 kernel/locking/rwsem.c:1520 __super_lock fs/super.c:58 [inline] super_lock+0x17f/0x3a0 fs/super.c:117 super_lock_shared fs/super.c:146 [inline] super_lock_shared_active fs/super.c:1442 [inline] fs_bdev_sync+0xa4/0x170 fs/super.c:1477 blkdev_flushbuf block/ioctl.c:381 [inline] blkdev_common_ioctl+0x8a6/0x2570 block/ioctl.c:511 blkdev_ioctl+0x512/0x730 block/ioctl.c:633 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:46 [inline] do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 other info that might help us debug this: Chain exists of: &type->s_umount_key#31 --> &disk->open_mutex --> &bdev->bd_holder_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&bdev->bd_holder_lock); lock(&disk->open_mutex); lock(&bdev->bd_holder_lock); rlock(&type->s_umount_key#31); *** DEADLOCK *** 1 lock held by syz.2.5112/24143: #0: ffff8880200bdd08 (&bdev->bd_holder_lock){+.+.}-{3:3}, at: blkdev_flushbuf block/ioctl.c:379 [inline] #0: ffff8880200bdd08 (&bdev->bd_holder_lock){+.+.}-{3:3}, at: blkdev_common_ioctl+0x835/0x2570 block/ioctl.c:511 stack backtrace: CPU: 0 PID: 24143 Comm: syz.2.5112 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 Call Trace: dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106 check_noncircular+0x2fc/0x400 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+0x2df1/0x7d40 kernel/locking/lockdep.c:5137 lock_acquire+0x19e/0x420 kernel/locking/lockdep.c:5754 down_read+0x46/0x2e0 kernel/locking/rwsem.c:1520 __super_lock fs/super.c:58 [inline] super_lock+0x17f/0x3a0 fs/super.c:117 super_lock_shared fs/super.c:146 [inline] super_lock_shared_active fs/super.c:1442 [inline] fs_bdev_sync+0xa4/0x170 fs/super.c:1477 blkdev_flushbuf block/ioctl.c:381 [inline] blkdev_common_ioctl+0x8a6/0x2570 block/ioctl.c:511 blkdev_ioctl+0x512/0x730 block/ioctl.c:633 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:46 [inline] do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fd5c719ce59 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fd5c8039028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fd5c7415fa0 RCX: 00007fd5c719ce59 RDX: 0000000000000000 RSI: 0000000000001261 RDI: 0000000000000004 RBP: 00007fd5c7232d6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fd5c7416038 R14: 00007fd5c7415fa0 R15: 00007ffda5d8e368