======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.7.723/7488 is trying to acquire lock:
ffff0000e2ab65e8 (&dquot->dq_lock){+.+.}-{3:3}, at: dquot_commit+0x54/0x1c8 fs/quota/dquot.c:532

but task is already holding lock:
ffff0000e29420a0 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_map_blocks+0x720/0x160c fs/ext4/inode.c:674

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+0x64/0x300 kernel/locking/rwsem.c:1520
       ext4_map_blocks+0x270/0x160c fs/ext4/inode.c:606
       ext4_getblk+0x178/0x680 fs/ext4/inode.c:892
       ext4_bread+0x3c/0x1a8 fs/ext4/inode.c:948
       ext4_quota_read+0x160/0x358 fs/ext4/super.c:7182
       read_blk fs/quota/quota_tree.c:61 [inline]
       find_tree_dqentry+0x178/0xc2c fs/quota/quota_tree.c:671
       find_tree_dqentry+0x4fc/0xc2c fs/quota/quota_tree.c:698
       find_tree_dqentry+0x4fc/0xc2c fs/quota/quota_tree.c:698
       find_tree_dqentry+0x4fc/0xc2c fs/quota/quota_tree.c:698
       find_dqentry fs/quota/quota_tree.c:716 [inline]
       qtree_read_dquot+0x45c/0x748 fs/quota/quota_tree.c:736
       v2_read_dquot+0xbc/0x118 fs/quota/quota_v2.c:336
       dquot_acquire+0x108/0x4b8 fs/quota/dquot.c:488
       ext4_acquire_dquot+0x270/0x420 fs/ext4/super.c:6837
       dqget+0x638/0xa98 fs/quota/dquot.c:1010
       __dquot_initialize+0x280/0xb30 fs/quota/dquot.c:1539
       dquot_initialize+0x24/0x34 fs/quota/dquot.c:1601
       ext4_process_orphan+0x5c/0x2c0 fs/ext4/orphan.c:327
       ext4_orphan_cleanup+0x964/0x1090 fs/ext4/orphan.c:472
       __ext4_fill_super fs/ext4/super.c:5574 [inline]
       ext4_fill_super+0x5af8/0x63bc fs/ext4/super.c:5693
       get_tree_bdev+0x35c/0x54c fs/super.c:1366
       ext4_get_tree+0x28/0x38 fs/ext4/super.c:5723
       vfs_get_tree+0x90/0x278 fs/super.c:1573
       do_new_mount+0x228/0x804 fs/namespace.c:3078
       path_mount+0x5ac/0xe6c fs/namespace.c:3408
       do_mount fs/namespace.c:3421 [inline]
       __do_sys_mount fs/namespace.c:3629 [inline]
       __se_sys_mount fs/namespace.c:3606 [inline]
       __arm64_sys_mount+0x4a0/0x5a0 fs/namespace.c:3606
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140
       do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204
       el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
       el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
       el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

-> #1 (&s->s_dquot.dqio_sem){++++}-{3:3}:
       down_read+0x64/0x300 kernel/locking/rwsem.c:1520
       v2_read_dquot+0x4c/0x118 fs/quota/quota_v2.c:335
       dquot_acquire+0x108/0x4b8 fs/quota/dquot.c:488
       ext4_acquire_dquot+0x270/0x420 fs/ext4/super.c:6837
       dqget+0x638/0xa98 fs/quota/dquot.c:1010
       __dquot_initialize+0x280/0xb30 fs/quota/dquot.c:1539
       dquot_initialize+0x24/0x34 fs/quota/dquot.c:1601
       ext4_process_orphan+0x5c/0x2c0 fs/ext4/orphan.c:327
       ext4_orphan_cleanup+0x964/0x1090 fs/ext4/orphan.c:472
       __ext4_fill_super fs/ext4/super.c:5574 [inline]
       ext4_fill_super+0x5af8/0x63bc fs/ext4/super.c:5693
       get_tree_bdev+0x35c/0x54c fs/super.c:1366
       ext4_get_tree+0x28/0x38 fs/ext4/super.c:5723
       vfs_get_tree+0x90/0x278 fs/super.c:1573
       do_new_mount+0x228/0x804 fs/namespace.c:3078
       path_mount+0x5ac/0xe6c fs/namespace.c:3408
       do_mount fs/namespace.c:3421 [inline]
       __do_sys_mount fs/namespace.c:3629 [inline]
       __se_sys_mount fs/namespace.c:3606 [inline]
       __arm64_sys_mount+0x4a0/0x5a0 fs/namespace.c:3606
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140
       do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204
       el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
       el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
       el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

-> #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+0x27c8/0x6610 kernel/locking/lockdep.c:5049
       lock_acquire+0x20c/0x638 kernel/locking/lockdep.c:5662
       __mutex_lock_common+0x1a0/0x1f3c kernel/locking/mutex.c:603
       __mutex_lock kernel/locking/mutex.c:747 [inline]
       mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799
       dquot_commit+0x54/0x1c8 fs/quota/dquot.c:532
       ext4_write_dquot+0x1b4/0x320 fs/ext4/super.c:6817
       ext4_mark_dquot_dirty+0xe8/0x150 fs/ext4/super.c:6894
       mark_dquot_dirty fs/quota/dquot.c:397 [inline]
       mark_all_dquot_dirty+0x108/0x424 fs/quota/dquot.c:437
       __dquot_alloc_space+0x564/0xcfc fs/quota/dquot.c:1774
       dquot_alloc_space_nodirty include/linux/quotaops.h:293 [inline]
       dquot_alloc_space include/linux/quotaops.h:306 [inline]
       dquot_alloc_block include/linux/quotaops.h:330 [inline]
       ext4_mb_new_blocks+0xd40/0x4244 fs/ext4/mballoc.c:5740
       ext4_ext_map_blocks+0x1330/0x563c fs/ext4/extents.c:4361
       ext4_map_blocks+0x7b0/0x160c fs/ext4/inode.c:681
       ext4_getblk+0x178/0x680 fs/ext4/inode.c:892
       ext4_bread+0x3c/0x1a8 fs/ext4/inode.c:948
       ext4_append+0x23c/0x488 fs/ext4/namei.c:83
       ext4_init_new_dir+0x270/0x4f0 fs/ext4/namei.c:3030
       ext4_mkdir+0x3b8/0xa28 fs/ext4/namei.c:3076
       vfs_mkdir+0x314/0x4d8 fs/namei.c:4114
       ovl_do_mkdir fs/overlayfs/overlayfs.h:186 [inline]
       ovl_mkdir_real+0xa8/0x204 fs/overlayfs/dir.c:146
       ovl_workdir_create+0x2c8/0x66c fs/overlayfs/super.c:799
       ovl_make_workdir fs/overlayfs/super.c:1389 [inline]
       ovl_get_workdir+0x31c/0x1084 fs/overlayfs/super.c:1539
       ovl_fill_super+0x17d0/0x3938 fs/overlayfs/super.c:2095
       mount_nodev+0x68/0x108 fs/super.c:1489
       ovl_mount+0x3c/0x50 fs/overlayfs/super.c:2186
       legacy_get_tree+0xd8/0x174 fs/fs_context.c:632
       vfs_get_tree+0x90/0x278 fs/super.c:1573
       do_new_mount+0x228/0x804 fs/namespace.c:3078
       path_mount+0x5ac/0xe6c fs/namespace.c:3408
       do_mount fs/namespace.c:3421 [inline]
       __do_sys_mount fs/namespace.c:3629 [inline]
       __se_sys_mount fs/namespace.c:3606 [inline]
       __arm64_sys_mount+0x4a0/0x5a0 fs/namespace.c:3606
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140
       do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204
       el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
       el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
       el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

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 ***

5 locks held by syz.7.723/7488:
 #0: ffff0000ff1740e0 (&type->s_umount_key#60/1){+.+.}-{3:3}, at: alloc_super+0x1a0/0x840 fs/super.c:228
 #1: ffff0000edcc6460 (sb_writers#3){.+.+}-{0:0}, at: mnt_want_write+0x44/0x9c fs/namespace.c:402
 #2: ffff0000e2941810 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:793 [inline]
 #2: ffff0000e2941810 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: ovl_workdir_create+0x128/0x66c fs/overlayfs/super.c:771
 #3: ffff0000e29420a0 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_map_blocks+0x720/0x160c fs/ext4/inode.c:674
 #4: ffff80001563c968 (dquot_srcu){....}-{0:0}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:349

stack backtrace:
CPU: 0 PID: 7488 Comm: syz.7.723 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/02/2026
Call trace:
 dump_backtrace+0x1c4/0x1f0 arch/arm64/kernel/stacktrace.c:158
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165
 __dump_stack+0x30/0x40 lib/dump_stack.c:88
 dump_stack_lvl+0xf4/0x15c lib/dump_stack.c:106
 dump_stack+0x1c/0x5c lib/dump_stack.c:113
 print_circular_bug+0x148/0x1b0 kernel/locking/lockdep.c:2048
 check_noncircular+0x264/0x2f8 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+0x27c8/0x6610 kernel/locking/lockdep.c:5049
 lock_acquire+0x20c/0x638 kernel/locking/lockdep.c:5662
 __mutex_lock_common+0x1a0/0x1f3c kernel/locking/mutex.c:603
 __mutex_lock kernel/locking/mutex.c:747 [inline]
 mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799
 dquot_commit+0x54/0x1c8 fs/quota/dquot.c:532
 ext4_write_dquot+0x1b4/0x320 fs/ext4/super.c:6817
 ext4_mark_dquot_dirty+0xe8/0x150 fs/ext4/super.c:6894
 mark_dquot_dirty fs/quota/dquot.c:397 [inline]
 mark_all_dquot_dirty+0x108/0x424 fs/quota/dquot.c:437
 __dquot_alloc_space+0x564/0xcfc fs/quota/dquot.c:1774
 dquot_alloc_space_nodirty include/linux/quotaops.h:293 [inline]
 dquot_alloc_space include/linux/quotaops.h:306 [inline]
 dquot_alloc_block include/linux/quotaops.h:330 [inline]
 ext4_mb_new_blocks+0xd40/0x4244 fs/ext4/mballoc.c:5740
 ext4_ext_map_blocks+0x1330/0x563c fs/ext4/extents.c:4361
 ext4_map_blocks+0x7b0/0x160c fs/ext4/inode.c:681
 ext4_getblk+0x178/0x680 fs/ext4/inode.c:892
 ext4_bread+0x3c/0x1a8 fs/ext4/inode.c:948
 ext4_append+0x23c/0x488 fs/ext4/namei.c:83
 ext4_init_new_dir+0x270/0x4f0 fs/ext4/namei.c:3030
 ext4_mkdir+0x3b8/0xa28 fs/ext4/namei.c:3076
 vfs_mkdir+0x314/0x4d8 fs/namei.c:4114
 ovl_do_mkdir fs/overlayfs/overlayfs.h:186 [inline]
 ovl_mkdir_real+0xa8/0x204 fs/overlayfs/dir.c:146
 ovl_workdir_create+0x2c8/0x66c fs/overlayfs/super.c:799
 ovl_make_workdir fs/overlayfs/super.c:1389 [inline]
 ovl_get_workdir+0x31c/0x1084 fs/overlayfs/super.c:1539
 ovl_fill_super+0x17d0/0x3938 fs/overlayfs/super.c:2095
 mount_nodev+0x68/0x108 fs/super.c:1489
 ovl_mount+0x3c/0x50 fs/overlayfs/super.c:2186
 legacy_get_tree+0xd8/0x174 fs/fs_context.c:632
 vfs_get_tree+0x90/0x278 fs/super.c:1573
 do_new_mount+0x228/0x804 fs/namespace.c:3078
 path_mount+0x5ac/0xe6c fs/namespace.c:3408
 do_mount fs/namespace.c:3421 [inline]
 __do_sys_mount fs/namespace.c:3629 [inline]
 __se_sys_mount fs/namespace.c:3606 [inline]
 __arm64_sys_mount+0x4a0/0x5a0 fs/namespace.c:3606
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585