syzbot

======================================================
WARNING: possible circular locking dependency detected
6.1.129-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor304/4649 is trying to acquire lock:
ffff88807004cce8 (&dquot->dq_lock){+.+.}-{3:3}, at: dquot_commit+0x57/0x510 fs/quota/dquot.c:507

but task is already holding lock:
ffff8880700734b0 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_map_blocks+0x955/0x1cb0 fs/ext4/inode.c:671

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&ei->i_data_sem/2){++++}-{3:3}:
       lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
       down_read+0xad/0xa30 kernel/locking/rwsem.c:1520
       ext4_map_blocks+0x379/0x1cb0 fs/ext4/inode.c:603
       ext4_getblk+0x1eb/0x7c0 fs/ext4/inode.c:889
       ext4_bread+0x2a/0x170 fs/ext4/inode.c:945
       ext4_quota_read+0x1ae/0x2d0 fs/ext4/super.c:7119
       read_blk fs/quota/quota_tree.c:61 [inline]
       find_tree_dqentry+0x1db/0x1020 fs/quota/quota_tree.c:671
       find_tree_dqentry+0x6eb/0x1020 fs/quota/quota_tree.c:698
       find_tree_dqentry+0x6eb/0x1020 fs/quota/quota_tree.c:698
       find_tree_dqentry+0x6eb/0x1020 fs/quota/quota_tree.c:698
       find_dqentry fs/quota/quota_tree.c:716 [inline]
       qtree_read_dquot+0x546/0x7f0 fs/quota/quota_tree.c:736
       v2_read_dquot+0xbe/0x100 fs/quota/quota_v2.c:336
       dquot_acquire+0x188/0x680 fs/quota/dquot.c:463
       ext4_acquire_dquot+0x2eb/0x4a0 fs/ext4/super.c:6791
       dqget+0x762/0xe90 fs/quota/dquot.c:988
       __dquot_initialize+0x45e/0xea0 fs/quota/dquot.c:1517
       ext4_process_orphan+0x57/0x2d0 fs/ext4/orphan.c:329
       ext4_orphan_cleanup+0xb70/0x1400 fs/ext4/orphan.c:474
       __ext4_fill_super fs/ext4/super.c:5523 [inline]
       ext4_fill_super+0x84b2/0x89e0 fs/ext4/super.c:5654
       get_tree_bdev+0x3fe/0x620 fs/super.c:1366
       vfs_get_tree+0x88/0x270 fs/super.c:1573
       do_new_mount+0x2ba/0xb40 fs/namespace.c:3056
       do_mount fs/namespace.c:3399 [inline]
       __do_sys_mount fs/namespace.c:3607 [inline]
       __se_sys_mount+0x2d5/0x3c0 fs/namespace.c:3584
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #1 (&s->s_dquot.dqio_sem){++++}-{3:3}:
       lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
       down_read+0xad/0xa30 kernel/locking/rwsem.c:1520
       v2_read_dquot+0x4a/0x100 fs/quota/quota_v2.c:335
       dquot_acquire+0x188/0x680 fs/quota/dquot.c:463
       ext4_acquire_dquot+0x2eb/0x4a0 fs/ext4/super.c:6791
       dqget+0x762/0xe90 fs/quota/dquot.c:988
       __dquot_initialize+0x45e/0xea0 fs/quota/dquot.c:1517
       ext4_process_orphan+0x57/0x2d0 fs/ext4/orphan.c:329
       ext4_orphan_cleanup+0xb70/0x1400 fs/ext4/orphan.c:474
       __ext4_fill_super fs/ext4/super.c:5523 [inline]
       ext4_fill_super+0x84b2/0x89e0 fs/ext4/super.c:5654
       get_tree_bdev+0x3fe/0x620 fs/super.c:1366
       vfs_get_tree+0x88/0x270 fs/super.c:1573
       do_new_mount+0x2ba/0xb40 fs/namespace.c:3056
       do_mount fs/namespace.c:3399 [inline]
       __do_sys_mount fs/namespace.c:3607 [inline]
       __se_sys_mount+0x2d5/0x3c0 fs/namespace.c:3584
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #0 (&dquot->dq_lock){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3090 [inline]
       check_prevs_add kernel/locking/lockdep.c:3209 [inline]
       validate_chain+0x1661/0x5950 kernel/locking/lockdep.c:3825
       __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049
       lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       __mutex_lock+0x132/0xd80 kernel/locking/mutex.c:747
       dquot_commit+0x57/0x510 fs/quota/dquot.c:507
       ext4_write_dquot+0x1fd/0x360 fs/ext4/super.c:6771
       mark_dquot_dirty fs/quota/dquot.c:372 [inline]
       mark_all_dquot_dirty+0xf7/0x400 fs/quota/dquot.c:412
       __dquot_alloc_space+0xb68/0x10e0 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+0x1302/0x4b80 fs/ext4/mballoc.c:5727
       ext4_ext_map_blocks+0x1c1c/0x7ab0 fs/ext4/extents.c:4339
       ext4_map_blocks+0xa2b/0x1cb0 fs/ext4/inode.c:678
       ext4_getblk+0x1eb/0x7c0 fs/ext4/inode.c:889
       ext4_bread+0x2a/0x170 fs/ext4/inode.c:945
       ext4_append+0x31f/0x5c0 fs/ext4/namei.c:83
       ext4_init_new_dir+0x33f/0x620 fs/ext4/namei.c:3030
       ext4_mkdir+0x4f2/0xce0 fs/ext4/namei.c:3076
       vfs_mkdir+0x3b6/0x590 fs/namei.c:4106
       do_mkdirat+0x225/0x360 fs/namei.c:4131
       __do_sys_mkdir fs/namei.c:4151 [inline]
       __se_sys_mkdir fs/namei.c:4149 [inline]
       __x64_sys_mkdir+0x6a/0x80 fs/namei.c:4149
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

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-executor304/4649:
 #0: ffff888028a2a460 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x3b/0x80 fs/namespace.c:393
 #1: ffff888075697258 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:793 [inline]
 #1: ffff888075697258 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: filename_create+0x25c/0x530 fs/namei.c:3876
 #2: ffff8880700734b0 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_map_blocks+0x955/0x1cb0 fs/ext4/inode.c:671
 #3: ffffffff8d479a28 (dquot_srcu){....}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #3: ffffffff8d479a28 (dquot_srcu){....}-{0:0}, at: srcu_read_lock include/linux/srcu.h:165 [inline]
 #3: ffffffff8d479a28 (dquot_srcu){....}-{0:0}, at: __dquot_alloc_space+0x1d6/0x10e0 fs/quota/dquot.c:1716

stack backtrace:
CPU: 0 PID: 4649 Comm: syz-executor304 Not tainted 6.1.129-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 check_noncircular+0x2fa/0x3b0 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+0x1661/0x5950 kernel/locking/lockdep.c:3825
 __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049
 lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
 __mutex_lock_common kernel/locking/mutex.c:603 [inline]
 __mutex_lock+0x132/0xd80 kernel/locking/mutex.c:747
 dquot_commit+0x57/0x510 fs/quota/dquot.c:507
 ext4_write_dquot+0x1fd/0x360 fs/ext4/super.c:6771
 mark_dquot_dirty fs/quota/dquot.c:372 [inline]
 mark_all_dquot_dirty+0xf7/0x400 fs/quota/dquot.c:412
 __dquot_alloc_space+0xb68/0x10e0 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+0x1302/0x4b80 fs/ext4/mballoc.c:5727
 ext4_ext_map_blocks+0x1c1c/0x7ab0 fs/ext4/extents.c:4339
 ext4_map_blocks+0xa2b/0x1cb0 fs/ext4/inode.c:678
 ext4_getblk+0x1eb/0x7c0 fs/ext4/inode.c:889
 ext4_bread+0x2a/0x170 fs/ext4/inode.c:945
 ext4_append+0x31f/0x5c0 fs/ext4/namei.c:83
 ext4_init_new_dir+0x33f/0x620 fs/ext4/namei.c:3030
 ext4_mkdir+0x4f2/0xce0 fs/ext4/namei.c:3076
 vfs_mkdir+0x3b6/0x590 fs/namei.c:4106
 do_mkdirat+0x225/0x360 fs/namei.c:4131
 __do_sys_mkdir fs/namei.c:4151 [inline]
 __se_sys_mkdir fs/namei.c:4149 [inline]
 __x64_sys_mkdir+0x6a/0x80 fs/namei.c:4149
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fc5efc7b4d9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 21 18 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe15fe4178 EFLAGS: 00000246 ORIG_RAX: 0000000000000053
RAX: ffffffffffffffda RBX: 00004000000000c0 RCX: 00007fc5efc7b4d9
RDX: 00007fc5efc7a670 RSI: 0000000000000000 RDI: 0000400000000280
RBP: 7261637369646f6e R08: 0000000000000552 R09: 00007ffe15fe41b0
R10: 00007ffe15fe4040 R11: 0000000000000246 R12: 00007ffe15fe419c
R13: 0000000000000027 R14: 0000400000000084 R15: 00007ffe15fe41d0
 </TASK>
EXT4-fs error (device loop0): ext4_do_update_inode:5224: inode #2: comm syz-executor304: corrupted inode contents
EXT4-fs error (device loop0): ext4_dirty_inode:6089: inode #2: comm syz-executor304: mark_inode_dirty error
EXT4-fs error (device loop0): ext4_do_update_inode:5224: inode #2: comm syz-executor304: corrupted inode contents
EXT4-fs error (device loop0): __ext4_ext_dirty:202: inode #2: comm syz-executor304: mark_inode_dirty error