EXT4-fs (loop2): Quota format mount options ignored when QUOTA feature is enabled
EXT4-fs (loop2): inline encryption not supported
EXT4-fs (loop2): feature flags set on rev 0 fs, running e2fsck is recommended
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.2.1365/8923 is trying to acquire lock:
ffff88807317d238 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_map_blocks+0x33c/0x1b30 fs/ext4/inode.c:600

but task is already holding lock:
ffff888020584208 (&s->s_dquot.dqio_sem){++++}-{3:3}, at: v2_read_dquot+0x4a/0x110 fs/quota/quota_v2.c:332

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+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+0x2d9/0x4a0 fs/ext4/super.c:6232
       dqget+0x72b/0xc30 fs/quota/dquot.c:1010
       __dquot_initialize+0x3c3/0xcd0 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+0x11db/0x2fa0 fs/namei.c:3747
       do_filp_open+0x1e2/0x410 fs/namei.c:3777
       do_sys_openat2+0x150/0x4b0 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

-> #1 (&dquot->dq_lock){+.+.}-{3:3}:
       __mutex_lock_common+0x1e3/0x2400 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+0x5d0/0xe20 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+0xfb1/0x4820 fs/ext4/mballoc.c:5750
       ext4_ext_map_blocks+0x18ab/0x65e0 fs/ext4/extents.c:4357
       ext4_map_blocks+0x98e/0x1b30 fs/ext4/inode.c:675
       ext4_alloc_file_blocks+0x378/0xb60 fs/ext4/extents.c:4544
       ext4_zero_range+0x4d4/0xde0 fs/ext4/extents.c:4661
       ext4_fallocate+0x538/0x1ed0 fs/ext4/extents.c:4796
       vfs_fallocate+0x587/0x6f0 fs/open.c:308
       ksys_fallocate fs/open.c:331 [inline]
       __do_sys_fallocate fs/open.c:339 [inline]
       __se_sys_fallocate fs/open.c:337 [inline]
       __x64_sys_fallocate+0xbd/0x100 fs/open.c:337
       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 (&ei->i_data_sem/2){++++}-{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+0x2c42/0x7d10 kernel/locking/lockdep.c:5012
       lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623
       down_read+0x44/0x2e0 kernel/locking/rwsem.c:1498
       ext4_map_blocks+0x33c/0x1b30 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_read+0x1b3/0x3a0 fs/ext4/super.c:6577
       read_blk fs/quota/quota_tree.c:55 [inline]
       find_tree_dqentry+0x188/0xb30 fs/quota/quota_tree.c:617
       find_tree_dqentry+0x3eb/0xb30 fs/quota/quota_tree.c:635
       find_tree_dqentry+0x3eb/0xb30 fs/quota/quota_tree.c:635
       find_tree_dqentry+0x3eb/0xb30 fs/quota/quota_tree.c:635
       find_dqentry fs/quota/quota_tree.c:647 [inline]
       qtree_read_dquot+0x13c/0x680 fs/quota/quota_tree.c:667
       v2_read_dquot+0xc0/0x110 fs/quota/quota_v2.c:333
       dquot_acquire+0x152/0x520 fs/quota/dquot.c:488
       ext4_acquire_dquot+0x2d9/0x4a0 fs/ext4/super.c:6232
       dqget+0x72b/0xc30 fs/quota/dquot.c:1010
       __dquot_initialize+0x333/0xcd0 fs/quota/dquot.c:1539
       ext4_process_orphan+0x54/0x300 fs/ext4/orphan.c:327
       ext4_orphan_cleanup+0xad2/0x1320 fs/ext4/orphan.c:472
       ext4_fill_super+0x8d6e/0x94f0 fs/ext4/super.c:5006
       mount_bdev+0x287/0x3c0 fs/super.c:1400
       legacy_get_tree+0xe6/0x180 fs/fs_context.c:611
       vfs_get_tree+0x88/0x270 fs/super.c:1530
       do_new_mount+0x24a/0xa40 fs/namespace.c:3034
       do_mount fs/namespace.c:3377 [inline]
       __do_sys_mount fs/namespace.c:3585 [inline]
       __se_sys_mount+0x2e3/0x3d0 fs/namespace.c:3562
       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:
  &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 ***

3 locks held by syz.2.1365/8923:
 #0: ffff8880205840e0 (&type->s_umount_key#28/1){+.+.}-{3:3}, at: alloc_super+0x201/0x950 fs/super.c:229
 #1: ffff8880731f2428 (&dquot->dq_lock){+.+.}-{3:3}, at: dquot_acquire+0x63/0x520 fs/quota/dquot.c:485
 #2: ffff888020584208 (&s->s_dquot.dqio_sem){++++}-{3:3}, at: v2_read_dquot+0x4a/0x110 fs/quota/quota_v2.c:332

stack backtrace:
CPU: 0 PID: 8923 Comm: syz.2.1365 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
 <TASK>
 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+0x2c42/0x7d10 kernel/locking/lockdep.c:5012
 lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623
 down_read+0x44/0x2e0 kernel/locking/rwsem.c:1498
 ext4_map_blocks+0x33c/0x1b30 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_read+0x1b3/0x3a0 fs/ext4/super.c:6577
 read_blk fs/quota/quota_tree.c:55 [inline]
 find_tree_dqentry+0x188/0xb30 fs/quota/quota_tree.c:617
 find_tree_dqentry+0x3eb/0xb30 fs/quota/quota_tree.c:635
 find_tree_dqentry+0x3eb/0xb30 fs/quota/quota_tree.c:635
 find_tree_dqentry+0x3eb/0xb30 fs/quota/quota_tree.c:635
 find_dqentry fs/quota/quota_tree.c:647 [inline]
 qtree_read_dquot+0x13c/0x680 fs/quota/quota_tree.c:667
 v2_read_dquot+0xc0/0x110 fs/quota/quota_v2.c:333
 dquot_acquire+0x152/0x520 fs/quota/dquot.c:488
 ext4_acquire_dquot+0x2d9/0x4a0 fs/ext4/super.c:6232
 dqget+0x72b/0xc30 fs/quota/dquot.c:1010
 __dquot_initialize+0x333/0xcd0 fs/quota/dquot.c:1539
 ext4_process_orphan+0x54/0x300 fs/ext4/orphan.c:327
 ext4_orphan_cleanup+0xad2/0x1320 fs/ext4/orphan.c:472
 ext4_fill_super+0x8d6e/0x94f0 fs/ext4/super.c:5006
 mount_bdev+0x287/0x3c0 fs/super.c:1400
 legacy_get_tree+0xe6/0x180 fs/fs_context.c:611
 vfs_get_tree+0x88/0x270 fs/super.c:1530
 do_new_mount+0x24a/0xa40 fs/namespace.c:3034
 do_mount fs/namespace.c:3377 [inline]
 __do_sys_mount fs/namespace.c:3585 [inline]
 __se_sys_mount+0x2e3/0x3d0 fs/namespace.c:3562
 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: 0033:0x7f00598860ca
Code: 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 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:00007f0057adde58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f0057addee0 RCX: 00007f00598860ca
RDX: 0000200000000040 RSI: 0000200000000000 RDI: 00007f0057addea0
RBP: 0000200000000040 R08: 00007f0057addee0 R09: 0000000002010000
R10: 0000000002010000 R11: 0000000000000246 R12: 0000200000000000
R13: 00007f0057addea0 R14: 0000000000000550 R15: 0000200000000140
 </TASK>
EXT4-fs warning (device loop2): ext4_update_dynamic_rev:1062: updating to rev 1 because of new feature flag, running e2fsck is recommended
EXT4-fs error (device loop2): ext4_validate_block_bitmap:438: comm syz.2.1365: bg 0: block 248: padding at end of block bitmap is not set
Quota error (device loop2): write_blk: dquota write failed
Quota error (device loop2): qtree_write_dquot: Error -28 occurred while creating quota
EXT4-fs error (device loop2): ext4_acquire_dquot:6236: comm syz.2.1365: Failed to acquire dquot type 1
EXT4-fs (loop2): 1 truncate cleaned up
EXT4-fs (loop2): mounted filesystem without journal. Opts: jqfmt=vfsold,inlinecrypt,nombcache,,errors=continue. Quota mode: writeback.