====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz-executor/4338 is trying to acquire lock: ffff0000f6371698 ( &ei->i_data_sem /2 ){++++}-{3:3} , at: ext4_map_blocks+0x270/0x160c fs/ext4/inode.c:606 but task is already holding lock: ffff0000d2f48208 (&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:491 ext4_acquire_dquot+0x270/0x420 fs/ext4/super.c:6844 dqget+0x638/0xa98 fs/quota/dquot.c:1013 __dquot_initialize+0x280/0xb30 fs/quota/dquot.c:1542 dquot_initialize+0x24/0x34 fs/quota/dquot.c:1604 ext4_process_orphan+0x5c/0x2c0 fs/ext4/orphan.c:327 ext4_orphan_cleanup+0xabc/0x1204 fs/ext4/orphan.c:472 __ext4_fill_super fs/ext4/super.c:5578 [inline] ext4_fill_super+0x5a30/0x63dc fs/ext4/super.c:5700 get_tree_bdev+0x35c/0x54c fs/super.c:1377 ext4_get_tree+0x28/0x38 fs/ext4/super.c:5730 vfs_get_tree+0x90/0x278 fs/super.c:1584 do_new_mount+0x228/0x818 fs/namespace.c:3104 path_mount+0x5ac/0xe6c fs/namespace.c:3462 do_mount fs/namespace.c:3475 [inline] __do_sys_mount fs/namespace.c:3683 [inline] __se_sys_mount fs/namespace.c:3660 [inline] __arm64_sys_mount+0x4a0/0x5a0 fs/namespace.c:3660 __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+0x58/0x12c 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:589 -> #1 (&dquot->dq_lock){+.+.}-{3:3}: __mutex_lock_common+0x1a0/0x1f88 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:535 ext4_write_dquot+0x1b4/0x320 fs/ext4/super.c:6824 ext4_mark_dquot_dirty+0xe8/0x150 fs/ext4/super.c:6901 mark_dquot_dirty fs/quota/dquot.c:400 [inline] mark_all_dquot_dirty+0x108/0x424 fs/quota/dquot.c:440 __dquot_free_space+0x768/0xaa4 fs/quota/dquot.c:1967 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:6168 [inline] ext4_free_blocks+0x18dc/0x2468 fs/ext4/mballoc.c:6298 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:4499 ext4_truncate+0xa00/0x1090 fs/ext4/inode.c:4305 ext4_evict_inode+0xbd0/0x1264 fs/ext4/inode.c:288 evict+0x3d8/0x81c fs/inode.c:703 iput_final fs/inode.c:1832 [inline] iput+0x728/0x7e8 fs/inode.c:1858 d_delete_notify include/linux/fsnotify.h:267 [inline] vfs_rmdir+0x32c/0x438 fs/namei.c:4259 do_rmdir+0x244/0x524 fs/namei.c:4307 __do_sys_unlinkat fs/namei.c:4487 [inline] __se_sys_unlinkat fs/namei.c:4481 [inline] __arm64_sys_unlinkat+0xcc/0xfc fs/namei.c:4481 __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+0x58/0x12c 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:589 -> #0 (&ei->i_data_sem/2){++++}-{3:3}: check_prev_add kernel/locking/lockdep.c:3162 [inline] check_prevs_add kernel/locking/lockdep.c:3281 [inline] validate_chain kernel/locking/lockdep.c:3897 [inline] __lock_acquire+0x3504/0x7280 kernel/locking/lockdep.c:5171 lock_acquire+0x210/0x63c kernel/locking/lockdep.c:5790 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:7223 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:500 ext4_acquire_dquot+0x270/0x420 fs/ext4/super.c:6844 dqget+0x638/0xa98 fs/quota/dquot.c:1013 __dquot_initialize+0x2e4/0xb30 fs/quota/dquot.c:1542 dquot_initialize+0x24/0x34 fs/quota/dquot.c:1604 ext4_unlink+0x18c/0x714 fs/ext4/namei.c:3368 vfs_unlink+0x2e0/0x4f4 fs/namei.c:4377 do_unlinkat+0x318/0x504 fs/namei.c:4445 __do_sys_unlinkat fs/namei.c:4488 [inline] __se_sys_unlinkat fs/namei.c:4481 [inline] __arm64_sys_unlinkat+0xe0/0xfc fs/namei.c:4481 __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+0x58/0x12c 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:589 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); rlock(&ei->i_data_sem/2); *** DEADLOCK *** 5 locks held by syz-executor/4338: #0: ffff0000d2f48460 (sb_writers#3){.+.+}-{0:0}, at: mnt_want_write+0x44/0x9c fs/namespace.c:402 #1: ffff0000f6375e48 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:799 [inline] #1: ffff0000f6375e48 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: do_unlinkat+0x184/0x504 fs/namei.c:4428 #2: ffff0000fa25c030 (&sb->s_type->i_mutex_key#10){++++}-{3:3}, at: inode_lock include/linux/fs.h:764 [inline] #2: ffff0000fa25c030 (&sb->s_type->i_mutex_key#10){++++}-{3:3}, at: vfs_unlink+0xd0/0x4f4 fs/namei.c:4366 #3: ffff0000f63500a8 (&dquot->dq_lock){+.+.}-{3:3}, at: dquot_acquire+0x60/0x4b8 fs/quota/dquot.c:488 #4: ffff0000d2f48208 (&s->s_dquot.dqio_sem){++++}-{3:3}, at: v2_write_dquot+0x114/0x180 fs/quota/quota_v2.c:357 stack backtrace: CPU: 0 PID: 4338 Comm: syz-executor Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/31/2026 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:2088 check_noncircular+0x290/0x370 kernel/locking/lockdep.c:2215 check_prev_add kernel/locking/lockdep.c:3162 [inline] check_prevs_add kernel/locking/lockdep.c:3281 [inline] validate_chain kernel/locking/lockdep.c:3897 [inline] __lock_acquire+0x3504/0x7280 kernel/locking/lockdep.c:5171 lock_acquire+0x210/0x63c kernel/locking/lockdep.c:5790 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:7223 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:500 ext4_acquire_dquot+0x270/0x420 fs/ext4/super.c:6844 dqget+0x638/0xa98 fs/quota/dquot.c:1013 __dquot_initialize+0x2e4/0xb30 fs/quota/dquot.c:1542 dquot_initialize+0x24/0x34 fs/quota/dquot.c:1604 ext4_unlink+0x18c/0x714 fs/ext4/namei.c:3368 vfs_unlink+0x2e0/0x4f4 fs/namei.c:4377 do_unlinkat+0x318/0x504 fs/namei.c:4445 __do_sys_unlinkat fs/namei.c:4488 [inline] __se_sys_unlinkat fs/namei.c:4481 [inline] __arm64_sys_unlinkat+0xe0/0xfc fs/namei.c:4481 __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+0x58/0x12c 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:589 EXT4-fs (loop3): unmounting filesystem.