====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.7.711/7148 is trying to acquire lock: ffff88805f0b4840 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_map_blocks+0x350/0x1a50 fs/ext4/inode.c:600 but task is already holding lock: ffff888054bae208 (&s->s_dquot.dqio_sem){++++}-{3:3}, at: v2_read_dquot+0x4a/0x110 fs/quota/quota_v2.c:332 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+0x44/0x2e0 kernel/locking/rwsem.c:1498 v2_read_dquot+0x4a/0x110 fs/quota/quota_v2.c:332 dquot_acquire+0x152/0x520 fs/quota/dquot.c:488 ext4_acquire_dquot+0x2e3/0x4a0 fs/ext4/super.c:6232 dqget+0x713/0xbb0 fs/quota/dquot.c:1010 __dquot_initialize+0x3a9/0xd00 fs/quota/dquot.c:1539 ext4_process_orphan+0x4c/0x2e0 fs/ext4/orphan.c:327 ext4_orphan_cleanup+0xad8/0x1320 fs/ext4/orphan.c:472 ext4_fill_super+0x8c65/0x93f0 fs/ext4/super.c:5006 mount_bdev+0x28a/0x3c0 fs/super.c:1400 legacy_get_tree+0xe6/0x180 fs/fs_context.c:611 vfs_get_tree+0x88/0x270 fs/super.c:1530 do_new_mount+0x247/0xa40 fs/namespace.c:3034 do_mount fs/namespace.c:3377 [inline] __do_sys_mount fs/namespace.c:3585 [inline] __se_sys_mount+0x2e3/0x3d0 fs/namespace.c:3562 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 -> #1 (&dquot->dq_lock){+.+.}-{3:3}: __mutex_lock_common+0x1e5/0x2400 kernel/locking/mutex.c:596 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743 dquot_commit+0x5a/0x410 fs/quota/dquot.c:532 ext4_write_dquot+0x1f0/0x360 fs/ext4/super.c:6212 mark_dquot_dirty fs/quota/dquot.c:397 [inline] mark_all_dquot_dirty+0xf9/0x400 fs/quota/dquot.c:437 __dquot_alloc_space+0x5cb/0xe10 fs/quota/dquot.c:1774 dquot_alloc_space_nodirty include/linux/quotaops.h:290 [inline] dquot_alloc_space include/linux/quotaops.h:303 [inline] dquot_alloc_block include/linux/quotaops.h:327 [inline] ext4_mb_new_blocks+0xf80/0x47c0 fs/ext4/mballoc.c:5750 ext4_ext_map_blocks+0x17d1/0x63d0 fs/ext4/extents.c:4372 ext4_map_blocks+0x97f/0x1a50 fs/ext4/inode.c:675 ext4_getblk+0x176/0x670 fs/ext4/inode.c:872 ext4_bread+0x26/0x180 fs/ext4/inode.c:925 ext4_append+0x2bb/0x560 fs/ext4/namei.c:83 ext4_init_new_dir+0x2a7/0x910 fs/ext4/namei.c:3030 ext4_mkdir+0x4c3/0xc90 fs/ext4/namei.c:3076 vfs_mkdir+0x386/0x570 fs/namei.c:4073 ovl_do_mkdir fs/overlayfs/overlayfs.h:166 [inline] ovl_mkdir_real+0x53/0x1a0 fs/overlayfs/dir.c:146 ovl_workdir_create+0x2fb/0x640 fs/overlayfs/super.c:796 ovl_make_workdir fs/overlayfs/super.c:1376 [inline] ovl_get_workdir+0x38f/0x12a0 fs/overlayfs/super.c:1526 ovl_fill_super+0x1cd4/0x42a0 fs/overlayfs/super.c:2082 mount_nodev+0x52/0xe0 fs/super.c:1446 legacy_get_tree+0xe6/0x180 fs/fs_context.c:611 vfs_get_tree+0x88/0x270 fs/super.c:1530 do_new_mount+0x247/0xa40 fs/namespace.c:3034 do_mount fs/namespace.c:3377 [inline] __do_sys_mount fs/namespace.c:3585 [inline] __se_sys_mount+0x2e3/0x3d0 fs/namespace.c:3562 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 -> #0 (&ei->i_data_sem/2){++++}-{3:3}: check_prev_add kernel/locking/lockdep.c:3053 [inline] check_prevs_add kernel/locking/lockdep.c:3172 [inline] validate_chain kernel/locking/lockdep.c:3788 [inline] __lock_acquire+0x2c66/0x7b50 kernel/locking/lockdep.c:5012 lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623 down_read+0x44/0x2e0 kernel/locking/rwsem.c:1498 ext4_map_blocks+0x350/0x1a50 fs/ext4/inode.c:600 ext4_getblk+0x176/0x670 fs/ext4/inode.c:872 ext4_bread+0x26/0x180 fs/ext4/inode.c:925 ext4_quota_read+0x1ac/0x390 fs/ext4/super.c:6577 read_blk fs/quota/quota_tree.c:55 [inline] find_tree_dqentry+0x187/0xb30 fs/quota/quota_tree.c:617 find_tree_dqentry+0x3e8/0xb30 fs/quota/quota_tree.c:635 find_tree_dqentry+0x3e8/0xb30 fs/quota/quota_tree.c:635 find_tree_dqentry+0x3e8/0xb30 fs/quota/quota_tree.c:635 find_dqentry fs/quota/quota_tree.c:647 [inline] qtree_read_dquot+0x122/0x690 fs/quota/quota_tree.c:667 v2_read_dquot+0xc0/0x110 fs/quota/quota_v2.c:333 dquot_acquire+0x152/0x520 fs/quota/dquot.c:488 ext4_acquire_dquot+0x2e3/0x4a0 fs/ext4/super.c:6232 dqget+0x713/0xbb0 fs/quota/dquot.c:1010 __dquot_initialize+0x324/0xd00 fs/quota/dquot.c:1539 ext4_xattr_set+0xc5/0x310 fs/ext4/xattr.c:2494 __vfs_removexattr+0x3b1/0x3f0 fs/xattr.c:470 __vfs_removexattr_locked+0x1e4/0x230 fs/xattr.c:505 vfs_removexattr+0x7d/0x1b0 fs/xattr.c:527 removexattr fs/xattr.c:857 [inline] path_removexattr+0x222/0x480 fs/xattr.c:871 __do_sys_lremovexattr fs/xattr.c:891 [inline] __se_sys_lremovexattr fs/xattr.c:888 [inline] __x64_sys_lremovexattr+0x59/0x70 fs/xattr.c:888 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 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 *** 4 locks held by syz.7.711/7148: #0: ffff888054bae460 (sb_writers#5){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:386 #1: ffff88805da95da8 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline] #1: ffff88805da95da8 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: vfs_removexattr+0x69/0x1b0 fs/xattr.c:526 #2: ffff88805d94eb28 (&dquot->dq_lock){+.+.}-{3:3}, at: dquot_acquire+0x63/0x520 fs/quota/dquot.c:485 #3: ffff888054bae208 (&s->s_dquot.dqio_sem){++++}-{3:3}, at: v2_read_dquot+0x4a/0x110 fs/quota/quota_v2.c:332 stack backtrace: CPU: 1 PID: 7148 Comm: syz.7.711 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Call Trace: dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106 check_noncircular+0x296/0x330 kernel/locking/lockdep.c:2133 check_prev_add kernel/locking/lockdep.c:3053 [inline] check_prevs_add kernel/locking/lockdep.c:3172 [inline] validate_chain kernel/locking/lockdep.c:3788 [inline] __lock_acquire+0x2c66/0x7b50 kernel/locking/lockdep.c:5012 lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623 down_read+0x44/0x2e0 kernel/locking/rwsem.c:1498 ext4_map_blocks+0x350/0x1a50 fs/ext4/inode.c:600 ext4_getblk+0x176/0x670 fs/ext4/inode.c:872 ext4_bread+0x26/0x180 fs/ext4/inode.c:925 ext4_quota_read+0x1ac/0x390 fs/ext4/super.c:6577 read_blk fs/quota/quota_tree.c:55 [inline] find_tree_dqentry+0x187/0xb30 fs/quota/quota_tree.c:617 find_tree_dqentry+0x3e8/0xb30 fs/quota/quota_tree.c:635 find_tree_dqentry+0x3e8/0xb30 fs/quota/quota_tree.c:635 find_tree_dqentry+0x3e8/0xb30 fs/quota/quota_tree.c:635 find_dqentry fs/quota/quota_tree.c:647 [inline] qtree_read_dquot+0x122/0x690 fs/quota/quota_tree.c:667 v2_read_dquot+0xc0/0x110 fs/quota/quota_v2.c:333 dquot_acquire+0x152/0x520 fs/quota/dquot.c:488 ext4_acquire_dquot+0x2e3/0x4a0 fs/ext4/super.c:6232 dqget+0x713/0xbb0 fs/quota/dquot.c:1010 __dquot_initialize+0x324/0xd00 fs/quota/dquot.c:1539 ext4_xattr_set+0xc5/0x310 fs/ext4/xattr.c:2494 __vfs_removexattr+0x3b1/0x3f0 fs/xattr.c:470 __vfs_removexattr_locked+0x1e4/0x230 fs/xattr.c:505 vfs_removexattr+0x7d/0x1b0 fs/xattr.c:527 removexattr fs/xattr.c:857 [inline] path_removexattr+0x222/0x480 fs/xattr.c:871 __do_sys_lremovexattr fs/xattr.c:891 [inline] __se_sys_lremovexattr fs/xattr.c:888 [inline] __x64_sys_lremovexattr+0x59/0x70 fs/xattr.c:888 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f0baf244e59 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:00007f0bad47c028 EFLAGS: 00000246 ORIG_RAX: 00000000000000c6 RAX: ffffffffffffffda RBX: 00007f0baf4cd090 RCX: 00007f0baf244e59 RDX: 0000000000000000 RSI: 0000200000000400 RDI: 0000200000000100 RBP: 00007f0baf2dae6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f0baf4cd128 R14: 00007f0baf4cd090 R15: 00007ffd0c8ee598 EXT4-fs warning (device loop7): ext4_update_dynamic_rev:1062: updating to rev 1 because of new feature flag, running e2fsck is recommended EXT4-fs error (device loop7): ext4_validate_block_bitmap:438: comm syz.7.711: bg 0: block 248: padding at end of block bitmap is not set Quota error (device loop7): write_blk: dquota write failed Quota error (device loop7): qtree_write_dquot: Error -28 occurred while creating quota EXT4-fs error (device loop7): ext4_acquire_dquot:6236: comm syz.7.711: Failed to acquire dquot type 1