====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.7.2088/11921 is trying to acquire lock: ffff8880743bf068 (&dquot->dq_lock){+.+.}-{3:3}, at: dquot_commit+0x5a/0x410 fs/quota/dquot.c:532 but task is already holding lock: ffff88805ce0b450 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_map_blocks+0x8c4/0x1a50 fs/ext4/inode.c:668 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&ei->i_data_sem/2){++++}-{3:3}: 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_write+0x237/0x580 fs/ext4/super.c:6623 write_blk fs/quota/quota_tree.c:64 [inline] get_free_dqblk+0x38a/0x7a0 fs/quota/quota_tree.c:125 do_insert_tree+0x21b/0x19c0 fs/quota/quota_tree.c:335 do_insert_tree+0x5c4/0x19c0 fs/quota/quota_tree.c:366 do_insert_tree+0x5c4/0x19c0 fs/quota/quota_tree.c:366 do_insert_tree+0x5c4/0x19c0 fs/quota/quota_tree.c:366 dq_insert_tree fs/quota/quota_tree.c:392 [inline] qtree_write_dquot+0x354/0x4a0 fs/quota/quota_tree.c:411 v2_write_dquot+0x108/0x190 fs/quota/quota_v2.c:358 dquot_acquire+0x2d5/0x520 fs/quota/dquot.c:497 ext4_acquire_dquot+0x2e3/0x4a0 fs/ext4/super.c:6232 dqget+0x713/0xbb0 fs/quota/dquot.c:1010 dquot_transfer+0x1eb/0x470 fs/quota/dquot.c:2168 ext4_setattr+0x743/0x1b70 fs/ext4/inode.c:5477 notify_change+0xbc6/0xee0 fs/attr.c:505 chown_common+0x4cc/0x680 fs/open.c:680 vfs_fchown fs/open.c:748 [inline] ksys_fchown+0xe2/0x150 fs/open.c:759 __do_sys_fchown fs/open.c:767 [inline] __se_sys_fchown fs/open.c:765 [inline] __x64_sys_fchown+0x76/0x80 fs/open.c:765 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 ( &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_create+0x92/0x470 fs/ext4/namei.c:2876 lookup_open fs/namei.c:3470 [inline] open_last_lookups fs/namei.c:3540 [inline] path_openat+0x120a/0x2fb0 fs/namei.c:3747 do_filp_open+0x1df/0x400 fs/namei.c:3777 do_sys_openat2+0x14b/0x500 fs/open.c:1255 do_sys_open fs/open.c:1271 [inline] __do_sys_openat fs/open.c:1287 [inline] __se_sys_openat fs/open.c:1282 [inline] __x64_sys_openat+0x135/0x160 fs/open.c:1282 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 (&dquot->dq_lock){+.+.}-{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 __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_alloc_branch fs/ext4/indirect.c:340 [inline] ext4_ind_map_blocks+0xf0a/0x2250 fs/ext4/indirect.c:635 ext4_map_blocks+0x929/0x1a50 fs/ext4/inode.c:677 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 do_mkdirat+0x1dd/0x5c0 fs/namei.c:4098 __do_sys_mkdir fs/namei.c:4118 [inline] __se_sys_mkdir fs/namei.c:4116 [inline] __x64_sys_mkdir+0x6a/0x80 fs/namei.c:4116 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: &dquot->dq_lock --> &s->s_dquot.dqio_sem --> &ei->i_data_sem/2 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&ei->i_data_sem/2); lock(&s->s_dquot.dqio_sem); lock(&ei->i_data_sem/2); lock(&dquot->dq_lock); *** DEADLOCK *** 4 locks held by syz.7.2088/11921: #0: ffff88807c638460 (sb_writers#5){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:386 #1: ffff88805ce0c9b8 (&type->i_mutex_dir_key#4/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:822 [inline] #1: ffff88805ce0c9b8 (&type->i_mutex_dir_key#4/1){+.+.}-{3:3}, at: filename_create+0x20b/0x450 fs/namei.c:3843 #2: ffff88805ce0b450 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_map_blocks+0x8c4/0x1a50 fs/ext4/inode.c:668 #3: ffffffff8c441798 (dquot_srcu){....}-{0:0}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:312 stack backtrace: CPU: 0 PID: 11921 Comm: syz.7.2088 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 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 __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_alloc_branch fs/ext4/indirect.c:340 [inline] ext4_ind_map_blocks+0xf0a/0x2250 fs/ext4/indirect.c:635 ext4_map_blocks+0x929/0x1a50 fs/ext4/inode.c:677 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 do_mkdirat+0x1dd/0x5c0 fs/namei.c:4098 __do_sys_mkdir fs/namei.c:4118 [inline] __se_sys_mkdir fs/namei.c:4116 [inline] __x64_sys_mkdir+0x6a/0x80 fs/namei.c:4116 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: 0033:0x7f05d4172e99 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:00007f05d23cb028 EFLAGS: 00000246 ORIG_RAX: 0000000000000053 RAX: ffffffffffffffda RBX: 00007f05d43fafa0 RCX: 00007f05d4172e99 RDX: 0000000000000000 RSI: 000000000000010d RDI: 0000200000000080 RBP: 00007f05d4208eaf R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f05d43fb038 R14: 00007f05d43fafa0 R15: 00007fffd8400c58