======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz-executor/4335 is trying to acquire lock:
ffff0000f5a3b4b0 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_map_blocks+0x270/0x160c fs/ext4/inode.c:606

but task is already holding lock:
ffff0000cc42c208 (&s->s_dquot.dqio_sem){++++}-{3:3}, at: v2_write_dquot+0x114/0x180 fs/quota/quota_v2.c:357

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+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+0x2e4/0xb30 fs/quota/dquot.c:1539
       dquot_initialize+0x24/0x34 fs/quota/dquot.c:1601
       ext4_create+0x9c/0x410 fs/ext4/namei.c:2876
       lookup_open fs/namei.c:3490 [inline]
       open_last_lookups fs/namei.c:3558 [inline]
       path_openat+0xda8/0x27a0 fs/namei.c:3788
       do_filp_open+0x198/0x38c fs/namei.c:3818
       do_sys_openat2+0x134/0x3fc fs/open.c:1320
       do_sys_open fs/open.c:1336 [inline]
       __do_sys_openat fs/open.c:1352 [inline]
       __se_sys_openat fs/open.c:1347 [inline]
       __arm64_sys_openat+0x11c/0x150 fs/open.c:1347
       __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 (&dquot->dq_lock){+.+.}-{3:3}:
       __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_free_space+0x768/0xaa4 fs/quota/dquot.c:1964
       dquot_free_space_nodirty include/linux/quotaops.h:372 [inline]
       dquot_free_space include/linux/quotaops.h:377 [inline]
       dquot_free_block include/linux/quotaops.h:388 [inline]
       ext4_mb_clear_bb fs/ext4/mballoc.c:6153 [inline]
       ext4_free_blocks+0x18dc/0x2468 fs/ext4/mballoc.c:6283
       ext4_remove_blocks fs/ext4/extents.c:2523 [inline]
       ext4_ext_rm_leaf fs/ext4/extents.c:2707 [inline]
       ext4_ext_remove_space+0x1978/0x3b98 fs/ext4/extents.c:2955
       ext4_ext_truncate+0x170/0x218 fs/ext4/extents.c:4491
       ext4_truncate+0xa00/0x1090 fs/ext4/inode.c:4302
       ext4_evict_inode+0xbd0/0x1264 fs/ext4/inode.c:288
       evict+0x3d8/0x824 fs/inode.c:705
       iput_final fs/inode.c:1834 [inline]
       iput+0x728/0x7e8 fs/inode.c:1860
       do_unlinkat+0x35c/0x504 fs/namei.c:4405
       __do_sys_unlinkat fs/namei.c:4441 [inline]
       __se_sys_unlinkat fs/namei.c:4434 [inline]
       __arm64_sys_unlinkat+0xe0/0xfc fs/namei.c:4434
       __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 (&ei->i_data_sem/2){++++}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3095 [inline]
       check_prevs_add kernel/locking/lockdep.c:3214 [inline]
       validate_chain kernel/locking/lockdep.c:3830 [inline]
       __lock_acquire+0x2808/0x6634 kernel/locking/lockdep.c:5063
       lock_acquire+0x20c/0x638 kernel/locking/lockdep.c:5676
       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_write+0x200/0x544 fs/ext4/super.c:7228
       write_blk fs/quota/quota_tree.c:70 [inline]
       get_free_dqblk+0x27c/0x570 fs/quota/quota_tree.c:136
       do_insert_tree+0x1ec/0xc68 fs/quota/quota_tree.c:347
       do_insert_tree+0x7dc/0xc68 fs/quota/quota_tree.c:402
       do_insert_tree+0x7dc/0xc68 fs/quota/quota_tree.c:402
       do_insert_tree+0x7dc/0xc68 fs/quota/quota_tree.c:402
       dq_insert_tree fs/quota/quota_tree.c:432 [inline]
       qtree_write_dquot+0x3d4/0x4e4 fs/quota/quota_tree.c:451
       v2_write_dquot+0xf0/0x180 fs/quota/quota_v2.c:361
       dquot_acquire+0x280/0x4b8 fs/quota/dquot.c:497
       ext4_acquire_dquot+0x270/0x420 fs/ext4/super.c:6837
       dqget+0x638/0xa98 fs/quota/dquot.c:1010
       __dquot_initialize+0x2e4/0xb30 fs/quota/dquot.c:1539
       dquot_initialize+0x24/0x34 fs/quota/dquot.c:1601
       ext4_unlink+0x18c/0x714 fs/ext4/namei.c:3366
       vfs_unlink+0x2e0/0x4f4 fs/namei.c:4330
       do_unlinkat+0x318/0x504 fs/namei.c:4398
       __do_sys_unlinkat fs/namei.c:4441 [inline]
       __se_sys_unlinkat fs/namei.c:4434 [inline]
       __arm64_sys_unlinkat+0xe0/0xfc fs/namei.c:4434
       __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:
  &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 ***

5 locks held by syz-executor/4335:
 #0: ffff0000cc42c460 (sb_writers#3){.+.+}-{0:0}, at: mnt_want_write+0x44/0x9c fs/namespace.c:402
 #1: ffff0000f5a38e08 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:793 [inline]
 #1: ffff0000f5a38e08 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: do_unlinkat+0x184/0x504 fs/namei.c:4381
 #2: ffff0000f58f8e08 (&sb->s_type->i_mutex_key#10){++++}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
 #2: ffff0000f58f8e08 (&sb->s_type->i_mutex_key#10){++++}-{3:3}, at: vfs_unlink+0xd0/0x4f4 fs/namei.c:4319
 #3: ffff0000e10d8428 (&dquot->dq_lock){+.+.}-{3:3}, at: dquot_acquire+0x60/0x4b8 fs/quota/dquot.c:485
 #4: ffff0000cc42c208 (&s->s_dquot.dqio_sem){++++}-{3:3}, at: v2_write_dquot+0x114/0x180 fs/quota/quota_v2.c:357

stack backtrace:
CPU: 0 PID: 4335 Comm: syz-executor Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/02/2026
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:3095 [inline]
 check_prevs_add kernel/locking/lockdep.c:3214 [inline]
 validate_chain kernel/locking/lockdep.c:3830 [inline]
 __lock_acquire+0x2808/0x6634 kernel/locking/lockdep.c:5063
 lock_acquire+0x20c/0x638 kernel/locking/lockdep.c:5676
 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_write+0x200/0x544 fs/ext4/super.c:7228
 write_blk fs/quota/quota_tree.c:70 [inline]
 get_free_dqblk+0x27c/0x570 fs/quota/quota_tree.c:136
 do_insert_tree+0x1ec/0xc68 fs/quota/quota_tree.c:347
 do_insert_tree+0x7dc/0xc68 fs/quota/quota_tree.c:402
 do_insert_tree+0x7dc/0xc68 fs/quota/quota_tree.c:402
 do_insert_tree+0x7dc/0xc68 fs/quota/quota_tree.c:402
 dq_insert_tree fs/quota/quota_tree.c:432 [inline]
 qtree_write_dquot+0x3d4/0x4e4 fs/quota/quota_tree.c:451
 v2_write_dquot+0xf0/0x180 fs/quota/quota_v2.c:361
 dquot_acquire+0x280/0x4b8 fs/quota/dquot.c:497
 ext4_acquire_dquot+0x270/0x420 fs/ext4/super.c:6837
 dqget+0x638/0xa98 fs/quota/dquot.c:1010
 __dquot_initialize+0x2e4/0xb30 fs/quota/dquot.c:1539
 dquot_initialize+0x24/0x34 fs/quota/dquot.c:1601
 ext4_unlink+0x18c/0x714 fs/ext4/namei.c:3366
 vfs_unlink+0x2e0/0x4f4 fs/namei.c:4330
 do_unlinkat+0x318/0x504 fs/namei.c:4398
 __do_sys_unlinkat fs/namei.c:4441 [inline]
 __se_sys_unlinkat fs/namei.c:4434 [inline]
 __arm64_sys_unlinkat+0xe0/0xfc fs/namei.c:4434
 __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
EXT4-fs (loop0): unmounting filesystem.