======================================================
WARNING: possible circular locking dependency detected
6.1.141-syzkaller #0 Not tainted
------------------------------------------------------
syz.3.359/6576 is trying to acquire lock:
ffff888074f8e428 (&dquot->dq_lock){+.+.}-{3:3}, at: dquot_commit+0x5a/0x410 fs/quota/dquot.c:507

but task is already holding lock:
ffff888072b29698 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_map_blocks+0x903/0x1b60 fs/ext4/inode.c:672

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+0x42/0x2d0 kernel/locking/rwsem.c:1520
       ext4_map_blocks+0x316/0x1b60 fs/ext4/inode.c:604
       ext4_getblk+0x1ab/0x6d0 fs/ext4/inode.c:890
       ext4_bread+0x26/0x170 fs/ext4/inode.c:946
       ext4_quota_read+0x180/0x380 fs/ext4/super.c:7155
       read_blk fs/quota/quota_tree.c:61 [inline]
       find_tree_dqentry+0x1cd/0xf30 fs/quota/quota_tree.c:671
       find_tree_dqentry+0x6b0/0xf30 fs/quota/quota_tree.c:698
       find_tree_dqentry+0x6b0/0xf30 fs/quota/quota_tree.c:698
       find_tree_dqentry+0x6b0/0xf30 fs/quota/quota_tree.c:698
       find_dqentry fs/quota/quota_tree.c:716 [inline]
       qtree_read_dquot+0x558/0x7f0 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:6810
       dqget+0x778/0xeb0 fs/quota/dquot.c:988
       __dquot_initialize+0x328/0xcb0 fs/quota/dquot.c:1517
       ext4_process_orphan+0x54/0x300 fs/ext4/orphan.c:329
       ext4_orphan_cleanup+0xbd3/0x1400 fs/ext4/orphan.c:474
       __ext4_fill_super fs/ext4/super.c:5535 [inline]
       ext4_fill_super+0x7b78/0x8110 fs/ext4/super.c:5666
       get_tree_bdev+0x3f1/0x610 fs/super.c:1366
       vfs_get_tree+0x88/0x270 fs/super.c:1573
       do_new_mount+0x24a/0xa40 fs/namespace.c:3054
       do_mount fs/namespace.c:3397 [inline]
       __do_sys_mount fs/namespace.c:3605 [inline]
       __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:3582
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #1 (&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:6810
       dqget+0x778/0xeb0 fs/quota/dquot.c:988
       __dquot_initialize+0x3b6/0xcb0 fs/quota/dquot.c:1517
       ext4_mknod+0x91/0x4a0 fs/ext4/namei.c:2911
       vfs_mknod+0x424/0x4c0 fs/namei.c:3985
       unix_bind_bsd net/unix/af_unix.c:1207 [inline]
       unix_bind+0x5bd/0xec0 net/unix/af_unix.c:1300
       __sys_bind+0x2f4/0x3f0 net/socket.c:1811
       __do_sys_bind net/socket.c:1822 [inline]
       __se_sys_bind net/socket.c:1820 [inline]
       __x64_sys_bind+0x76/0x80 net/socket.c:1820
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x4c/0xa0 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 kernel/locking/lockdep.c:3825 [inline]
       __lock_acquire+0x2cf8/0x7c50 kernel/locking/lockdep.c:5049
       lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       __mutex_lock+0x120/0xaf0 kernel/locking/mutex.c:747
       dquot_commit+0x5a/0x410 fs/quota/dquot.c:507
       ext4_write_dquot+0x1f0/0x360 fs/ext4/super.c:6790
       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+0xf74/0x4720 fs/ext4/mballoc.c:5727
       ext4_ext_map_blocks+0x143c/0x66d0 fs/ext4/extents.c:4339
       ext4_map_blocks+0x9d1/0x1b60 fs/ext4/inode.c:679
       ext4_getblk+0x1ab/0x6d0 fs/ext4/inode.c:890
       ext4_bread+0x26/0x170 fs/ext4/inode.c:946
       ext4_append+0x2c3/0x560 fs/ext4/namei.c:83
       ext4_add_entry+0x8f0/0xd90 fs/ext4/namei.c:2511
       ext4_add_nondir+0x93/0x270 fs/ext4/namei.c:2845
       ext4_create+0x2e0/0x460 fs/ext4/namei.c:2891
       lookup_open fs/namei.c:3482 [inline]
       open_last_lookups fs/namei.c:3550 [inline]
       path_openat+0x1187/0x2e70 fs/namei.c:3780
       do_filp_open+0x1c1/0x3c0 fs/namei.c:3810
       do_sys_openat2+0x142/0x490 fs/open.c:1318
       do_sys_open fs/open.c:1334 [inline]
       __do_sys_openat fs/open.c:1350 [inline]
       __se_sys_openat fs/open.c:1345 [inline]
       __x64_sys_openat+0x135/0x160 fs/open.c:1345
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x4c/0xa0 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.3.359/6576:
 #0: ffff888077266460 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:393
 #1: ffff888072b29810 (&type->i_mutex_dir_key#3){++++}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
 #1: ffff888072b29810 (&type->i_mutex_dir_key#3){++++}-{3:3}, at: open_last_lookups fs/namei.c:3547 [inline]
 #1: ffff888072b29810 (&type->i_mutex_dir_key#3){++++}-{3:3}, at: path_openat+0x7c2/0x2e70 fs/namei.c:3780
 #2: ffff888072b29698 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_map_blocks+0x903/0x1b60 fs/ext4/inode.c:672
 #3: ffffffff8ca74d08 (dquot_srcu){....}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #3: ffffffff8ca74d08 (dquot_srcu){....}-{0:0}, at: srcu_read_lock include/linux/srcu.h:165 [inline]
 #3: ffffffff8ca74d08 (dquot_srcu){....}-{0:0}, at: __dquot_alloc_space+0x173/0xe60 fs/quota/dquot.c:1716

stack backtrace:
CPU: 1 PID: 6576 Comm: syz.3.359 Not tainted 6.1.141-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106
 check_noncircular+0x274/0x310 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+0x2cf8/0x7c50 kernel/locking/lockdep.c:5049
 lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662
 __mutex_lock_common kernel/locking/mutex.c:603 [inline]
 __mutex_lock+0x120/0xaf0 kernel/locking/mutex.c:747
 dquot_commit+0x5a/0x410 fs/quota/dquot.c:507
 ext4_write_dquot+0x1f0/0x360 fs/ext4/super.c:6790
 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+0xf74/0x4720 fs/ext4/mballoc.c:5727
 ext4_ext_map_blocks+0x143c/0x66d0 fs/ext4/extents.c:4339
 ext4_map_blocks+0x9d1/0x1b60 fs/ext4/inode.c:679
 ext4_getblk+0x1ab/0x6d0 fs/ext4/inode.c:890
 ext4_bread+0x26/0x170 fs/ext4/inode.c:946
 ext4_append+0x2c3/0x560 fs/ext4/namei.c:83
 ext4_add_entry+0x8f0/0xd90 fs/ext4/namei.c:2511
 ext4_add_nondir+0x93/0x270 fs/ext4/namei.c:2845
 ext4_create+0x2e0/0x460 fs/ext4/namei.c:2891
 lookup_open fs/namei.c:3482 [inline]
 open_last_lookups fs/namei.c:3550 [inline]
 path_openat+0x1187/0x2e70 fs/namei.c:3780
 do_filp_open+0x1c1/0x3c0 fs/namei.c:3810
 do_sys_openat2+0x142/0x490 fs/open.c:1318
 do_sys_open fs/open.c:1334 [inline]
 __do_sys_openat fs/open.c:1350 [inline]
 __se_sys_openat fs/open.c:1345 [inline]
 __x64_sys_openat+0x135/0x160 fs/open.c:1345
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f247e98e929
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f247f882038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f247ebb6160 RCX: 00007f247e98e929
RDX: 000000000000275a RSI: 0000200000000140 RDI: ffffffffffffff9c
RBP: 00007f247ea10b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f247ebb6160 R15: 00007ffda5537508
 </TASK>
EXT4-fs error (device loop3): ext4_do_update_inode:5253: inode #2: comm syz.3.359: corrupted inode contents
EXT4-fs error (device loop3): ext4_dirty_inode:6118: inode #2: comm syz.3.359: mark_inode_dirty error
EXT4-fs error (device loop3): ext4_do_update_inode:5253: inode #2: comm syz.3.359: corrupted inode contents
EXT4-fs error (device loop3): __ext4_ext_dirty:202: inode #2: comm syz.3.359: mark_inode_dirty error