EXT4-fs (loop0): mounted filesystem without journal. Quota mode: writeback. ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.0.1118/9953 is trying to acquire lock: ffff0000f69352c8 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_map_blocks+0x278/0x1778 fs/ext4/inode.c:604 but task is already holding lock: ffff0000d2e42208 (&s->s_dquot.dqio_sem){++++}-{3:3}, at: v2_read_dquot+0x4c/0x118 fs/quota/quota_v2.c:335 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+0x120/0x4d8 fs/quota/dquot.c:463 ext4_acquire_dquot+0x270/0x428 fs/ext4/super.c:6831 dqget+0x654/0xcc4 fs/quota/dquot.c:988 __dquot_initialize+0x2fc/0xacc fs/quota/dquot.c:1517 dquot_initialize+0x24/0x34 fs/quota/dquot.c:1579 ext4_mkdir+0x150/0xa1c fs/ext4/namei.c:3059 vfs_mkdir+0x314/0x4d4 fs/namei.c:4114 do_mkdirat+0x1b8/0x3ec fs/namei.c:4139 __do_sys_mkdirat fs/namei.c:4154 [inline] __se_sys_mkdirat fs/namei.c:4152 [inline] __arm64_sys_mkdirat+0x90/0xa8 fs/namei.c:4152 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x58/0x130 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+0x190/0x1f60 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+0x50/0x1c4 fs/quota/dquot.c:507 ext4_write_dquot+0x1b4/0x31c fs/ext4/super.c:6811 ext4_mark_dquot_dirty+0xe8/0x140 fs/ext4/super.c:6888 mark_dquot_dirty fs/quota/dquot.c:372 [inline] mark_all_dquot_dirty+0x108/0x424 fs/quota/dquot.c:412 __dquot_alloc_space+0x560/0xce0 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+0xd48/0x4338 fs/ext4/mballoc.c:5738 ext4_ext_map_blocks+0x1394/0x56f4 fs/ext4/extents.c:4340 ext4_map_blocks+0x860/0x1778 fs/ext4/inode.c:679 _ext4_get_block+0x19c/0x4d8 fs/ext4/inode.c:822 ext4_get_block+0x4c/0x60 fs/ext4/inode.c:839 ext4_block_write_begin+0x50c/0x10e4 fs/ext4/inode.c:1124 ext4_write_begin+0x5f4/0x131c fs/ext4/ext4_jbd2.h:-1 ext4_da_write_begin+0x348/0x990 fs/ext4/inode.c:3000 generic_perform_write+0x234/0x4f4 mm/filemap.c:3862 ext4_buffered_write_iter+0x2c4/0x528 fs/ext4/file.c:285 ext4_file_write_iter+0x18c/0x1574 fs/ext4/file.c:-1 call_write_iter include/linux/fs.h:2265 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x3ec/0x7f0 fs/read_write.c:584 ksys_write+0x12c/0x224 fs/read_write.c:637 __do_sys_write fs/read_write.c:649 [inline] __se_sys_write fs/read_write.c:646 [inline] __arm64_sys_write+0x7c/0x90 fs/read_write.c:646 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x58/0x130 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:3090 [inline] check_prevs_add kernel/locking/lockdep.c:3209 [inline] validate_chain kernel/locking/lockdep.c:3825 [inline] __lock_acquire+0x2880/0x6800 kernel/locking/lockdep.c:5049 lock_acquire+0x20c/0x63c kernel/locking/lockdep.c:5662 down_read+0x64/0x300 kernel/locking/rwsem.c:1520 ext4_map_blocks+0x278/0x1778 fs/ext4/inode.c:604 ext4_getblk+0x178/0x664 fs/ext4/inode.c:890 ext4_bread+0x3c/0x1a8 fs/ext4/inode.c:946 ext4_quota_read+0x160/0x350 fs/ext4/super.c:7176 read_blk fs/quota/quota_tree.c:61 [inline] find_tree_dqentry+0x174/0xc04 fs/quota/quota_tree.c:671 find_dqentry fs/quota/quota_tree.c:716 [inline] qtree_read_dquot+0x49c/0x774 fs/quota/quota_tree.c:736 v2_read_dquot+0xbc/0x118 fs/quota/quota_v2.c:336 dquot_acquire+0x120/0x4d8 fs/quota/dquot.c:463 ext4_acquire_dquot+0x270/0x428 fs/ext4/super.c:6831 dqget+0x654/0xcc4 fs/quota/dquot.c:988 __dquot_initialize+0x2fc/0xacc fs/quota/dquot.c:1517 dquot_initialize+0x24/0x34 fs/quota/dquot.c:1579 ext4_setattr+0x22c/0x150c fs/ext4/inode.c:5497 notify_change+0xb0c/0xdcc fs/attr.c:499 chown_common+0x420/0x594 fs/open.c:736 vfs_fchown fs/open.c:804 [inline] ksys_fchown+0xe0/0x158 fs/open.c:815 __do_sys_fchown fs/open.c:823 [inline] __se_sys_fchown fs/open.c:821 [inline] __arm64_sys_fchown+0x7c/0x94 fs/open.c:821 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x58/0x130 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 *** 4 locks held by syz.0.1118/9953: #0: ffff0000d2e42460 (sb_writers#3){.+.+}-{0:0}, at: mnt_want_write_file+0x64/0x1e8 fs/namespace.c:446 #1: ffff0000f6930400 (&type->i_mutex_dir_key#3){++++}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline] #1: ffff0000f6930400 (&type->i_mutex_dir_key#3){++++}-{3:3}, at: chown_common+0x2b8/0x594 fs/open.c:726 #2: ffff0000f6972268 (&dquot->dq_lock){+.+.}-{3:3}, at: dquot_acquire+0x60/0x4d8 fs/quota/dquot.c:460 #3: ffff0000d2e42208 (&s->s_dquot.dqio_sem){++++}-{3:3}, at: v2_read_dquot+0x4c/0x118 fs/quota/quota_v2.c:335 stack backtrace: CPU: 0 PID: 9953 Comm: syz.0.1118 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/03/2025 Call trace: dump_backtrace+0x1c0/0x1ec 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+0x2880/0x6800 kernel/locking/lockdep.c:5049 lock_acquire+0x20c/0x63c kernel/locking/lockdep.c:5662 down_read+0x64/0x300 kernel/locking/rwsem.c:1520 ext4_map_blocks+0x278/0x1778 fs/ext4/inode.c:604 ext4_getblk+0x178/0x664 fs/ext4/inode.c:890 ext4_bread+0x3c/0x1a8 fs/ext4/inode.c:946 ext4_quota_read+0x160/0x350 fs/ext4/super.c:7176 read_blk fs/quota/quota_tree.c:61 [inline] find_tree_dqentry+0x174/0xc04 fs/quota/quota_tree.c:671 find_dqentry fs/quota/quota_tree.c:716 [inline] qtree_read_dquot+0x49c/0x774 fs/quota/quota_tree.c:736 v2_read_dquot+0xbc/0x118 fs/quota/quota_v2.c:336 dquot_acquire+0x120/0x4d8 fs/quota/dquot.c:463 ext4_acquire_dquot+0x270/0x428 fs/ext4/super.c:6831 dqget+0x654/0xcc4 fs/quota/dquot.c:988 __dquot_initialize+0x2fc/0xacc fs/quota/dquot.c:1517 dquot_initialize+0x24/0x34 fs/quota/dquot.c:1579 ext4_setattr+0x22c/0x150c fs/ext4/inode.c:5497 notify_change+0xb0c/0xdcc fs/attr.c:499 chown_common+0x420/0x594 fs/open.c:736 vfs_fchown fs/open.c:804 [inline] ksys_fchown+0xe0/0x158 fs/open.c:815 __do_sys_fchown fs/open.c:823 [inline] __se_sys_fchown fs/open.c:821 [inline] __arm64_sys_fchown+0x7c/0x94 fs/open.c:821 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x58/0x130 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