EXT4-fs (loop0): mounted filesystem without journal. Quota mode: writeback. ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.0.1084/9118 is trying to acquire lock: ffff888070f6e6d8 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_map_blocks+0x323/0x1b70 fs/ext4/inode.c:606 but task is already holding lock: ffff88805157e208 (&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:463 ext4_acquire_dquot+0x2d9/0x4a0 fs/ext4/super.c:6837 dqget+0x778/0xeb0 fs/quota/dquot.c:988 __dquot_initialize+0x3c3/0xcd0 fs/quota/dquot.c:1517 ext4_mkdir+0x1a5/0xce0 fs/ext4/namei.c:3059 vfs_mkdir+0x387/0x570 fs/namei.c:4114 do_mkdirat+0x1d8/0x440 fs/namei.c:4139 __do_sys_mkdirat fs/namei.c:4154 [inline] __se_sys_mkdirat fs/namei.c:4152 [inline] __x64_sys_mkdirat+0x85/0x90 fs/namei.c:4152 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/0xaf0 kernel/locking/mutex.c:747 dquot_commit+0x5a/0x410 fs/quota/dquot.c:507 ext4_write_dquot+0x1f0/0x360 fs/ext4/super.c:6817 mark_dquot_dirty fs/quota/dquot.c:372 [inline] mark_all_dquot_dirty+0xf9/0x400 fs/quota/dquot.c:412 __dquot_alloc_space+0x5fc/0xe60 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+0xfc4/0x4610 fs/ext4/mballoc.c:5740 ext4_ext_map_blocks+0x195b/0x6810 fs/ext4/extents.c:4346 ext4_map_blocks+0x9de/0x1b70 fs/ext4/inode.c:681 ext4_getblk+0x1cc/0x6f0 fs/ext4/inode.c:892 ext4_bread+0x26/0x170 fs/ext4/inode.c:948 ext4_append+0x2be/0x560 fs/ext4/namei.c:83 ext4_init_new_dir+0x2b8/0x570 fs/ext4/namei.c:3030 ext4_mkdir+0x4fb/0xce0 fs/ext4/namei.c:3076 vfs_mkdir+0x387/0x570 fs/namei.c:4114 do_mkdirat+0x1d8/0x440 fs/namei.c:4139 __do_sys_mkdirat fs/namei.c:4154 [inline] __se_sys_mkdirat fs/namei.c:4152 [inline] __x64_sys_mkdirat+0x85/0x90 fs/namei.c:4152 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:3090 [inline] check_prevs_add kernel/locking/lockdep.c:3209 [inline] validate_chain kernel/locking/lockdep.c:3825 [inline] __lock_acquire+0x2d07/0x7d10 kernel/locking/lockdep.c:5049 lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5662 down_read+0x42/0x2d0 kernel/locking/rwsem.c:1520 ext4_map_blocks+0x323/0x1b70 fs/ext4/inode.c:606 ext4_getblk+0x1cc/0x6f0 fs/ext4/inode.c:892 ext4_bread+0x26/0x170 fs/ext4/inode.c:948 ext4_quota_read+0x180/0x380 fs/ext4/super.c:7182 read_blk fs/quota/quota_tree.c:61 [inline] find_tree_dqentry+0x1cd/0xf30 fs/quota/quota_tree.c:671 find_dqentry fs/quota/quota_tree.c:716 [inline] qtree_read_dquot+0x57b/0x820 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:463 ext4_acquire_dquot+0x2d9/0x4a0 fs/ext4/super.c:6837 dqget+0x778/0xeb0 fs/quota/dquot.c:988 __dquot_initialize+0x3c3/0xcd0 fs/quota/dquot.c:1517 ext4_mkdir+0x1a5/0xce0 fs/ext4/namei.c:3059 vfs_mkdir+0x387/0x570 fs/namei.c:4114 do_mkdirat+0x1d8/0x440 fs/namei.c:4139 __do_sys_mkdirat fs/namei.c:4154 [inline] __se_sys_mkdirat fs/namei.c:4152 [inline] __x64_sys_mkdirat+0x85/0x90 fs/namei.c:4152 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 ---- ---- 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.0.1084/9118: #0: ffff88805157e460 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:402 #1: ffff888070f6d440 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:793 [inline] #1: ffff888070f6d440 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: filename_create+0x208/0x470 fs/namei.c:3884 #2: ffff888070e7a0a8 (&dquot->dq_lock){+.+.}-{3:3}, at: dquot_acquire+0x63/0x520 fs/quota/dquot.c:460 #3: ffff88805157e208 (&s->s_dquot.dqio_sem){++++}-{3:3}, at: v2_read_dquot+0x4a/0x110 fs/quota/quota_v2.c:335 stack backtrace: CPU: 0 PID: 9118 Comm: syz.0.1084 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 Call Trace: dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106 check_noncircular+0x296/0x330 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+0x2d07/0x7d10 kernel/locking/lockdep.c:5049 lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5662 down_read+0x42/0x2d0 kernel/locking/rwsem.c:1520 ext4_map_blocks+0x323/0x1b70 fs/ext4/inode.c:606 ext4_getblk+0x1cc/0x6f0 fs/ext4/inode.c:892 ext4_bread+0x26/0x170 fs/ext4/inode.c:948 ext4_quota_read+0x180/0x380 fs/ext4/super.c:7182 read_blk fs/quota/quota_tree.c:61 [inline] find_tree_dqentry+0x1cd/0xf30 fs/quota/quota_tree.c:671 find_dqentry fs/quota/quota_tree.c:716 [inline] qtree_read_dquot+0x57b/0x820 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:463 ext4_acquire_dquot+0x2d9/0x4a0 fs/ext4/super.c:6837 dqget+0x778/0xeb0 fs/quota/dquot.c:988 __dquot_initialize+0x3c3/0xcd0 fs/quota/dquot.c:1517 ext4_mkdir+0x1a5/0xce0 fs/ext4/namei.c:3059 vfs_mkdir+0x387/0x570 fs/namei.c:4114 do_mkdirat+0x1d8/0x440 fs/namei.c:4139 __do_sys_mkdirat fs/namei.c:4154 [inline] __se_sys_mkdirat fs/namei.c:4152 [inline] __x64_sys_mkdirat+0x85/0x90 fs/namei.c:4152 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: 0033:0x7ffb5579bc47 Code: 00 66 90 48 89 f2 b9 00 01 00 00 48 89 fe bf 9c ff ff ff e9 db f7 ff ff 66 2e 0f 1f 84 00 00 00 00 00 90 b8 02 01 00 00 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:00007ffb566dae58 EFLAGS: 00000246 ORIG_RAX: 0000000000000102 RAX: ffffffffffffffda RBX: 00007ffb566daee0 RCX: 00007ffb5579bc47 RDX: 00000000000001ff RSI: 00002000000000c0 RDI: 00000000ffffff9c RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00002000000000c0 R13: 00007ffb566daea0 R14: 0000000000000000 R15: 0000000000000000