loop8: detected capacity change from 0 to 512 EXT4-fs (loop8): feature flags set on rev 0 fs, running e2fsck is recommended ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.8.2682/14434 is trying to acquire lock: ffff0000f68c0c90 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_map_blocks+0x278/0x1778 fs/ext4/inode.c:606 but task is already holding lock: ffff0000ceece208 (&s->s_dquot.dqio_sem){++++}-{3:3}, at: v2_read_dquot+0x4c/0x118 fs/quota/quota_v2.c:335 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&s->s_dquot.dqio_sem){++++}-{3:3}: down_read+0x64/0x300 kernel/locking/rwsem.c:1520 v2_read_dquot+0x4c/0x118 fs/quota/quota_v2.c:335 dquot_acquire+0x120/0x4d8 fs/quota/dquot.c:463 ext4_acquire_dquot+0x270/0x428 fs/ext4/super.c:6837 dqget+0x654/0xcc4 fs/quota/dquot.c:988 __dquot_initialize+0x294/0xacc fs/quota/dquot.c:1517 dquot_initialize+0x24/0x34 fs/quota/dquot.c:1579 ext4_process_orphan+0x5c/0x2b4 fs/ext4/orphan.c:327 ext4_orphan_cleanup+0x920/0x1060 fs/ext4/orphan.c:472 __ext4_fill_super fs/ext4/super.c:5574 [inline] ext4_fill_super+0x594c/0x61b0 fs/ext4/super.c:5693 get_tree_bdev+0x358/0x544 fs/super.c:1366 ext4_get_tree+0x28/0x38 fs/ext4/super.c:5723 vfs_get_tree+0x90/0x274 fs/super.c:1573 do_new_mount+0x228/0x810 fs/namespace.c:3078 path_mount+0x5bc/0xe80 fs/namespace.c:3408 do_mount fs/namespace.c:3421 [inline] __do_sys_mount fs/namespace.c:3629 [inline] __se_sys_mount fs/namespace.c:3606 [inline] __arm64_sys_mount+0x49c/0x59c fs/namespace.c:3606 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585 -> #1 (&dquot->dq_lock){+.+.}-{3:3}: __mutex_lock_common+0x190/0x1f60 kernel/locking/mutex.c:603 __mutex_lock kernel/locking/mutex.c:747 [inline] mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799 dquot_commit+0x50/0x1c4 fs/quota/dquot.c:507 ext4_write_dquot+0x1b4/0x31c fs/ext4/super.c:6817 ext4_mark_dquot_dirty+0xe8/0x140 fs/ext4/super.c:6894 mark_dquot_dirty fs/quota/dquot.c:372 [inline] mark_all_dquot_dirty+0x108/0x424 fs/quota/dquot.c:412 __dquot_alloc_space+0x560/0xce0 fs/quota/dquot.c:1752 dquot_alloc_space_nodirty include/linux/quotaops.h:300 [inline] dquot_alloc_space include/linux/quotaops.h:313 [inline] dquot_alloc_block include/linux/quotaops.h:337 [inline] ext4_mb_new_blocks+0xd38/0x4254 fs/ext4/mballoc.c:5740 ext4_ext_map_blocks+0x1394/0x56f4 fs/ext4/extents.c:4346 ext4_map_blocks+0x860/0x1778 fs/ext4/inode.c:681 ext4_alloc_file_blocks+0x2ac/0x8ec fs/ext4/extents.c:4530 ext4_zero_range+0x3b4/0xcf8 fs/ext4/extents.c:4647 ext4_fallocate+0x438/0x1b54 fs/ext4/extents.c:4782 vfs_fallocate+0x4a4/0x5f4 fs/open.c:323 ioctl_preallocate+0x20c/0x2b4 fs/ioctl.c:290 file_ioctl fs/ioctl.c:-1 [inline] do_vfs_ioctl+0x1874/0x2100 fs/ioctl.c:849 __do_sys_ioctl fs/ioctl.c:868 [inline] __se_sys_ioctl fs/ioctl.c:856 [inline] __arm64_sys_ioctl+0xe4/0x1c8 fs/ioctl.c:856 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585 -> #0 (&ei->i_data_sem/2){++++}-{3:3}: check_prev_add kernel/locking/lockdep.c:3090 [inline] check_prevs_add kernel/locking/lockdep.c:3209 [inline] validate_chain kernel/locking/lockdep.c:3825 [inline] __lock_acquire+0x2880/0x6800 kernel/locking/lockdep.c:5049 lock_acquire+0x20c/0x63c kernel/locking/lockdep.c:5662 down_read+0x64/0x300 kernel/locking/rwsem.c:1520 ext4_map_blocks+0x278/0x1778 fs/ext4/inode.c:606 ext4_getblk+0x178/0x664 fs/ext4/inode.c:892 ext4_bread+0x3c/0x1a8 fs/ext4/inode.c:948 ext4_quota_read+0x160/0x350 fs/ext4/super.c:7182 read_blk fs/quota/quota_tree.c:61 [inline] find_tree_dqentry+0x174/0xc04 fs/quota/quota_tree.c:671 find_tree_dqentry+0x4f8/0xc04 fs/quota/quota_tree.c:698 find_dqentry fs/quota/quota_tree.c:716 [inline] qtree_read_dquot+0x49c/0x774 fs/quota/quota_tree.c:736 v2_read_dquot+0xbc/0x118 fs/quota/quota_v2.c:336 dquot_acquire+0x120/0x4d8 fs/quota/dquot.c:463 ext4_acquire_dquot+0x270/0x428 fs/ext4/super.c:6837 dqget+0x654/0xcc4 fs/quota/dquot.c:988 __dquot_initialize+0x294/0xacc fs/quota/dquot.c:1517 dquot_initialize+0x24/0x34 fs/quota/dquot.c:1579 ext4_process_orphan+0x5c/0x2b4 fs/ext4/orphan.c:327 ext4_orphan_cleanup+0x920/0x1060 fs/ext4/orphan.c:472 __ext4_fill_super fs/ext4/super.c:5574 [inline] ext4_fill_super+0x594c/0x61b0 fs/ext4/super.c:5693 get_tree_bdev+0x358/0x544 fs/super.c:1366 ext4_get_tree+0x28/0x38 fs/ext4/super.c:5723 vfs_get_tree+0x90/0x274 fs/super.c:1573 do_new_mount+0x228/0x810 fs/namespace.c:3078 path_mount+0x5bc/0xe80 fs/namespace.c:3408 do_mount fs/namespace.c:3421 [inline] __do_sys_mount fs/namespace.c:3629 [inline] __se_sys_mount fs/namespace.c:3606 [inline] __arm64_sys_mount+0x49c/0x59c fs/namespace.c:3606 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585 other info that might help us debug this: Chain exists of: &ei->i_data_sem/2 --> &dquot->dq_lock --> &s->s_dquot.dqio_sem Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&s->s_dquot.dqio_sem); lock(&dquot->dq_lock); lock(&s->s_dquot.dqio_sem); lock(&ei->i_data_sem/2); *** DEADLOCK *** 3 locks held by syz.8.2682/14434: #0: ffff0000ceece0e0 (&type->s_umount_key#26/1){+.+.}-{3:3}, at: alloc_super+0x1a4/0x800 fs/super.c:228 #1: ffff0000f6a46b28 (&dquot->dq_lock){+.+.}-{3:3}, at: dquot_acquire+0x60/0x4d8 fs/quota/dquot.c:460 #2: ffff0000ceece208 (&s->s_dquot.dqio_sem){++++}-{3:3}, at: v2_read_dquot+0x4c/0x118 fs/quota/quota_v2.c:335 stack backtrace: CPU: 1 PID: 14434 Comm: syz.8.2682 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Call trace: dump_backtrace+0x1c0/0x1ec arch/arm64/kernel/stacktrace.c:158 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165 __dump_stack+0x30/0x40 lib/dump_stack.c:88 dump_stack_lvl+0xf4/0x15c lib/dump_stack.c:106 dump_stack+0x1c/0x5c lib/dump_stack.c:113 print_circular_bug+0x148/0x1b0 kernel/locking/lockdep.c:2048 check_noncircular+0x264/0x2f8 kernel/locking/lockdep.c:2170 check_prev_add kernel/locking/lockdep.c:3090 [inline] check_prevs_add kernel/locking/lockdep.c:3209 [inline] validate_chain kernel/locking/lockdep.c:3825 [inline] __lock_acquire+0x2880/0x6800 kernel/locking/lockdep.c:5049 lock_acquire+0x20c/0x63c kernel/locking/lockdep.c:5662 down_read+0x64/0x300 kernel/locking/rwsem.c:1520 ext4_map_blocks+0x278/0x1778 fs/ext4/inode.c:606 ext4_getblk+0x178/0x664 fs/ext4/inode.c:892 ext4_bread+0x3c/0x1a8 fs/ext4/inode.c:948 ext4_quota_read+0x160/0x350 fs/ext4/super.c:7182 read_blk fs/quota/quota_tree.c:61 [inline] find_tree_dqentry+0x174/0xc04 fs/quota/quota_tree.c:671 find_tree_dqentry+0x4f8/0xc04 fs/quota/quota_tree.c:698 find_dqentry fs/quota/quota_tree.c:716 [inline] qtree_read_dquot+0x49c/0x774 fs/quota/quota_tree.c:736 v2_read_dquot+0xbc/0x118 fs/quota/quota_v2.c:336 dquot_acquire+0x120/0x4d8 fs/quota/dquot.c:463 ext4_acquire_dquot+0x270/0x428 fs/ext4/super.c:6837 dqget+0x654/0xcc4 fs/quota/dquot.c:988 __dquot_initialize+0x294/0xacc fs/quota/dquot.c:1517 dquot_initialize+0x24/0x34 fs/quota/dquot.c:1579 ext4_process_orphan+0x5c/0x2b4 fs/ext4/orphan.c:327 ext4_orphan_cleanup+0x920/0x1060 fs/ext4/orphan.c:472 __ext4_fill_super fs/ext4/super.c:5574 [inline] ext4_fill_super+0x594c/0x61b0 fs/ext4/super.c:5693 get_tree_bdev+0x358/0x544 fs/super.c:1366 ext4_get_tree+0x28/0x38 fs/ext4/super.c:5723 vfs_get_tree+0x90/0x274 fs/super.c:1573 do_new_mount+0x228/0x810 fs/namespace.c:3078 path_mount+0x5bc/0xe80 fs/namespace.c:3408 do_mount fs/namespace.c:3421 [inline] __do_sys_mount fs/namespace.c:3629 [inline] __se_sys_mount fs/namespace.c:3606 [inline] __arm64_sys_mount+0x49c/0x59c fs/namespace.c:3606 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585 EXT4-fs error (device loop8): ext4_mb_generate_buddy:1126: group 0, block bitmap and bg descriptor inconsistent: 48 vs 41 free clusters __quota_error: 9 callbacks suppressed Quota error (device loop8): write_blk: dquota write failed Quota error (device loop8): find_free_dqentry: Can't write quota data block 5 Quota error (device loop8): write_blk: dquota write failed Quota error (device loop8): qtree_write_dquot: Error -28 occurred while creating quota EXT4-fs error (device loop8): ext4_acquire_dquot:6841: comm syz.8.2682: Failed to acquire dquot type 1 EXT4-fs (loop8): 1 truncate cleaned up EXT4-fs (loop8): mounted filesystem without journal. Quota mode: writeback. EXT4-fs: Ignoring removed bh option