====================================================== WARNING: possible circular locking dependency detected 6.6.0-rc5-syzkaller-00171-gce583d5fb9d3 #0 Not tainted ------------------------------------------------------ syz-executor.1/7728 is trying to acquire lock: ffff8880744ea0e0 (&type->s_umount_key#24){++++}-{3:3}, at: __super_lock fs/super.c:58 [inline] ffff8880744ea0e0 (&type->s_umount_key#24){++++}-{3:3}, at: super_lock+0x176/0x390 fs/super.c:117 but task is already holding lock: ffff888148853a88 (&bdev->bd_holder_lock){+.+.}-{3:3}, at: blkdev_flushbuf block/ioctl.c:370 [inline] ffff888148853a88 (&bdev->bd_holder_lock){+.+.}-{3:3}, at: blkdev_common_ioctl+0x81e/0x2860 block/ioctl.c:502 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+0x136/0xd60 kernel/locking/mutex.c:747 bdev_mark_dead+0x32/0x1a0 block/bdev.c:961 disk_force_media_change+0x145/0x1c0 block/disk-events.c:302 __loop_clr_fd+0x3df/0x690 drivers/block/loop.c:1174 blkdev_put+0x5d2/0x770 erofs_kill_sb+0x5f/0x1a0 fs/erofs/super.c:888 deactivate_locked_super+0xa4/0x110 fs/super.c:481 cleanup_mnt+0x426/0x4c0 fs/namespace.c:1254 task_work_run+0x24a/0x300 kernel/task_work.c:180 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop+0xde/0x100 kernel/entry/common.c:171 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:204 __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline] syscall_exit_to_user_mode+0x64/0x280 kernel/entry/common.c:296 do_syscall_64+0x4d/0xc0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x63/0xcd -> #1 (&disk->open_mutex){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x136/0xd60 kernel/locking/mutex.c:747 blkdev_get_by_dev+0x137/0x620 block/bdev.c:786 journal_init_dev fs/reiserfs/journal.c:2626 [inline] journal_init+0xd0a/0x2460 fs/reiserfs/journal.c:2786 reiserfs_fill_super+0x1039/0x2620 fs/reiserfs/super.c:2022 mount_bdev+0x237/0x300 fs/super.c:1629 legacy_get_tree+0xef/0x190 fs/fs_context.c:638 vfs_get_tree+0x8c/0x280 fs/super.c:1750 do_new_mount+0x28f/0xae0 fs/namespace.c:3335 do_mount fs/namespace.c:3675 [inline] __do_sys_mount fs/namespace.c:3884 [inline] __se_sys_mount+0x2d9/0x3c0 fs/namespace.c:3861 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd -> #0 (&type->s_umount_key#24){++++}-{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:3868 [inline] __lock_acquire+0x39ff/0x7f70 kernel/locking/lockdep.c:5136 lock_acquire+0x1e3/0x520 kernel/locking/lockdep.c:5753 down_read+0xb1/0xa40 kernel/locking/rwsem.c:1520 __super_lock fs/super.c:58 [inline] super_lock+0x176/0x390 fs/super.c:117 super_lock_shared fs/super.c:146 [inline] super_lock_shared_active fs/super.c:1431 [inline] fs_bdev_sync+0xa5/0x170 fs/super.c:1466 blkdev_flushbuf block/ioctl.c:372 [inline] blkdev_common_ioctl+0x889/0x2860 block/ioctl.c:502 blkdev_ioctl+0x520/0x730 block/ioctl.c:624 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:871 [inline] __se_sys_ioctl+0xf8/0x170 fs/ioctl.c:857 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd other info that might help us debug this: Chain exists of: &type->s_umount_key#24 --> &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#24); *** DEADLOCK *** 1 lock held by syz-executor.1/7728: #0: ffff888148853a88 (&bdev->bd_holder_lock){+.+.}-{3:3}, at: blkdev_flushbuf block/ioctl.c:370 [inline] #0: ffff888148853a88 (&bdev->bd_holder_lock){+.+.}-{3:3}, at: blkdev_common_ioctl+0x81e/0x2860 block/ioctl.c:502 stack backtrace: CPU: 0 PID: 7728 Comm: syz-executor.1 Not tainted 6.6.0-rc5-syzkaller-00171-gce583d5fb9d3 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/06/2023 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e7/0x2d0 lib/dump_stack.c:106 check_noncircular+0x375/0x4a0 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:3868 [inline] __lock_acquire+0x39ff/0x7f70 kernel/locking/lockdep.c:5136 lock_acquire+0x1e3/0x520 kernel/locking/lockdep.c:5753 down_read+0xb1/0xa40 kernel/locking/rwsem.c:1520 __super_lock fs/super.c:58 [inline] super_lock+0x176/0x390 fs/super.c:117 super_lock_shared fs/super.c:146 [inline] super_lock_shared_active fs/super.c:1431 [inline] fs_bdev_sync+0xa5/0x170 fs/super.c:1466 blkdev_flushbuf block/ioctl.c:372 [inline] blkdev_common_ioctl+0x889/0x2860 block/ioctl.c:502 blkdev_ioctl+0x520/0x730 block/ioctl.c:624 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:871 [inline] __se_sys_ioctl+0xf8/0x170 fs/ioctl.c:857 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f19b7c7cae9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 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 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f19b8aa40c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f19b7d9bf80 RCX: 00007f19b7c7cae9 RDX: 0000000000000000 RSI: 0000000000001261 RDI: 0000000000000003 RBP: 00007f19b7cc847a R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007f19b7d9bf80 R15: 00007ffe03397968