====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.0.1029/8519 is trying to acquire lock: ffff888053be8c90 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_map_blocks+0x338/0x1a90 fs/ext4/inode.c:606 but task is already holding lock: ffff888054b08208 (&s->s_dquot.dqio_sem){++++}-{3:3}, at: v2_read_dquot+0x4a/0x110 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+0x42/0x2d0 kernel/locking/rwsem.c:1520 v2_read_dquot+0x4a/0x110 fs/quota/quota_v2.c:335 dquot_acquire+0x152/0x520 fs/quota/dquot.c:491 ext4_acquire_dquot+0x2e3/0x4a0 fs/ext4/super.c:6844 dqget+0x713/0xbb0 fs/quota/dquot.c:1013 __dquot_initialize+0x3a9/0xd00 fs/quota/dquot.c:1542 ext4_mknod+0x97/0x480 fs/ext4/namei.c:2913 vfs_mknod+0x430/0x4c0 fs/namei.c:4040 do_mknodat+0x356/0x4d0 fs/namei.c:-1 __do_sys_mknodat fs/namei.c:4118 [inline] __se_sys_mknodat fs/namei.c:4115 [inline] __x64_sys_mknodat+0xa5/0xc0 fs/namei.c:4115 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 -> #1 (&dquot->dq_lock){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x12d/0xb40 kernel/locking/mutex.c:747 dquot_commit+0x5a/0x410 fs/quota/dquot.c:535 ext4_write_dquot+0x1f0/0x360 fs/ext4/super.c:6824 mark_dquot_dirty fs/quota/dquot.c:400 [inline] mark_all_dquot_dirty+0xf9/0x400 fs/quota/dquot.c:440 __dquot_alloc_space+0x5f6/0xe50 fs/quota/dquot.c:1777 dquot_alloc_space_nodirty include/linux/quotaops.h:293 [inline] dquot_alloc_space include/linux/quotaops.h:306 [inline] dquot_alloc_block include/linux/quotaops.h:330 [inline] ext4_mb_new_blocks+0xf55/0x44d0 fs/ext4/mballoc.c:5755 ext4_ext_map_blocks+0x184a/0x6680 fs/ext4/extents.c:4369 ext4_map_blocks+0x9d7/0x1a90 fs/ext4/inode.c:681 ext4_getblk+0x1c5/0x720 fs/ext4/inode.c:892 ext4_bread+0x26/0x170 fs/ext4/inode.c:948 ext4_append+0x2bb/0x560 fs/ext4/namei.c:83 ext4_add_entry+0x8eb/0xda0 fs/ext4/namei.c:2513 ext4_add_nondir+0x93/0x270 fs/ext4/namei.c:2847 ext4_mknod+0x2df/0x480 fs/ext4/namei.c:2927 vfs_mknod+0x430/0x4c0 fs/namei.c:4040 do_mknodat+0x356/0x4d0 fs/namei.c:-1 __do_sys_mknodat fs/namei.c:4118 [inline] __se_sys_mknodat fs/namei.c:4115 [inline] __x64_sys_mknodat+0xa5/0xc0 fs/namei.c:4115 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 -> #0 (&ei->i_data_sem/2){++++}-{3:3}: check_prev_add kernel/locking/lockdep.c:3162 [inline] check_prevs_add kernel/locking/lockdep.c:3281 [inline] validate_chain kernel/locking/lockdep.c:3897 [inline] __lock_acquire+0x3a03/0x7ea0 kernel/locking/lockdep.c:5171 lock_acquire+0x1bc/0x4a0 kernel/locking/lockdep.c:5790 down_read+0x42/0x2d0 kernel/locking/rwsem.c:1520 ext4_map_blocks+0x338/0x1a90 fs/ext4/inode.c:606 ext4_getblk+0x1c5/0x720 fs/ext4/inode.c:892 ext4_bread+0x26/0x170 fs/ext4/inode.c:948 ext4_quota_read+0x17f/0x380 fs/ext4/super.c:7177 read_blk fs/quota/quota_tree.c:61 [inline] find_tree_dqentry+0x1cc/0xf40 fs/quota/quota_tree.c:671 find_tree_dqentry+0x6ac/0xf40 fs/quota/quota_tree.c:698 find_tree_dqentry+0x6ac/0xf40 fs/quota/quota_tree.c:698 find_tree_dqentry+0x6ac/0xf40 fs/quota/quota_tree.c:698 find_dqentry fs/quota/quota_tree.c:716 [inline] qtree_read_dquot+0x59a/0x880 fs/quota/quota_tree.c:736 v2_read_dquot+0xc0/0x110 fs/quota/quota_v2.c:336 dquot_acquire+0x152/0x520 fs/quota/dquot.c:491 ext4_acquire_dquot+0x2e3/0x4a0 fs/ext4/super.c:6844 dqget+0x713/0xbb0 fs/quota/dquot.c:1013 __dquot_initialize+0x324/0xd00 fs/quota/dquot.c:1542 ext4_mkdir+0x198/0xc90 fs/ext4/namei.c:3061 vfs_mkdir+0x386/0x570 fs/namei.c:4161 do_mkdirat+0x1d8/0x440 fs/namei.c:4186 __do_sys_mkdirat fs/namei.c:4201 [inline] __se_sys_mkdirat fs/namei.c:4199 [inline] __x64_sys_mkdirat+0x85/0x90 fs/namei.c:4199 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/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: &ei->i_data_sem/2 --> &dquot->dq_lock --> &s->s_dquot.dqio_sem Possible unsafe locking scenario: CPU0 CPU1 ---- ---- rlock(&s->s_dquot.dqio_sem); lock(&dquot->dq_lock); lock(&s->s_dquot.dqio_sem); rlock(&ei->i_data_sem/2); *** DEADLOCK *** 4 locks held by syz.0.1029/8519: #0: ffff888054b08460 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:402 #1: ffff88804c9f5e48 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:799 [inline] #1: ffff88804c9f5e48 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: filename_create+0x20b/0x450 fs/namei.c:3931 #2: ffff8880538e0968 (&dquot->dq_lock){+.+.}-{3:3}, at: dquot_acquire+0x63/0x520 fs/quota/dquot.c:488 #3: ffff888054b08208 (&s->s_dquot.dqio_sem){++++}-{3:3}, at: v2_read_dquot+0x4a/0x110 fs/quota/quota_v2.c:335 stack backtrace: CPU: 0 PID: 8519 Comm: syz.0.1029 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/06/2026 Call Trace: dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106 check_noncircular+0x2f8/0x400 kernel/locking/lockdep.c:2215 check_prev_add kernel/locking/lockdep.c:3162 [inline] check_prevs_add kernel/locking/lockdep.c:3281 [inline] validate_chain kernel/locking/lockdep.c:3897 [inline] __lock_acquire+0x3a03/0x7ea0 kernel/locking/lockdep.c:5171 lock_acquire+0x1bc/0x4a0 kernel/locking/lockdep.c:5790 down_read+0x42/0x2d0 kernel/locking/rwsem.c:1520 ext4_map_blocks+0x338/0x1a90 fs/ext4/inode.c:606 ext4_getblk+0x1c5/0x720 fs/ext4/inode.c:892 ext4_bread+0x26/0x170 fs/ext4/inode.c:948 ext4_quota_read+0x17f/0x380 fs/ext4/super.c:7177 read_blk fs/quota/quota_tree.c:61 [inline] find_tree_dqentry+0x1cc/0xf40 fs/quota/quota_tree.c:671 find_tree_dqentry+0x6ac/0xf40 fs/quota/quota_tree.c:698 find_tree_dqentry+0x6ac/0xf40 fs/quota/quota_tree.c:698 find_tree_dqentry+0x6ac/0xf40 fs/quota/quota_tree.c:698 find_dqentry fs/quota/quota_tree.c:716 [inline] qtree_read_dquot+0x59a/0x880 fs/quota/quota_tree.c:736 v2_read_dquot+0xc0/0x110 fs/quota/quota_v2.c:336 dquot_acquire+0x152/0x520 fs/quota/dquot.c:491 ext4_acquire_dquot+0x2e3/0x4a0 fs/ext4/super.c:6844 dqget+0x713/0xbb0 fs/quota/dquot.c:1013 __dquot_initialize+0x324/0xd00 fs/quota/dquot.c:1542 ext4_mkdir+0x198/0xc90 fs/ext4/namei.c:3061 vfs_mkdir+0x386/0x570 fs/namei.c:4161 do_mkdirat+0x1d8/0x440 fs/namei.c:4186 __do_sys_mkdirat fs/namei.c:4201 [inline] __se_sys_mkdirat fs/namei.c:4199 [inline] __x64_sys_mkdirat+0x85/0x90 fs/namei.c:4199 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f171199fb19 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:00007f17128a3028 EFLAGS: 00000246 ORIG_RAX: 0000000000000102 RAX: ffffffffffffffda RBX: 00007f1711c26270 RCX: 00007f171199fb19 RDX: 00000000000001ff RSI: 0000200000007280 RDI: ffffffffffffff9c RBP: 00007f1711a37b70 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f1711c26308 R14: 00007f1711c26270 R15: 00007ffcc3f1df48 Quota error (device loop0): write_blk: dquota write failed Quota error (device loop0): qtree_write_dquot: Error -28 occurred while creating quota EXT4-fs error (device loop0): ext4_acquire_dquot:6848: comm syz.0.1029: Failed to acquire dquot type 1