loop6: detected capacity change from 0 to 512 EXT4-fs (loop6): mounted filesystem without journal. Quota mode: writeback. ====================================================== WARNING: possible circular locking dependency detected 6.1.142-syzkaller #0 Not tainted ------------------------------------------------------ syz.6.1033/10599 is trying to acquire lock: ffff0000f58cd228 (&dquot->dq_lock){+.+.}-{3:3}, at: dquot_commit+0x50/0x1c4 fs/quota/dquot.c:507 but task is already holding lock: ffff0001030bdcd0 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_map_blocks+0x7c4/0x1770 fs/ext4/inode.c:672 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_write+0x5c/0x88 kernel/locking/rwsem.c:1573 ext4_map_blocks+0x7c4/0x1770 fs/ext4/inode.c:672 ext4_getblk+0x170/0x654 fs/ext4/inode.c:890 ext4_bread+0x3c/0x1b0 fs/ext4/inode.c:946 ext4_quota_write+0x228/0x51c fs/ext4/super.c:7201 write_blk fs/quota/quota_tree.c:70 [inline] find_free_dqentry+0x548/0xa68 fs/quota/quota_tree.c:318 do_insert_tree+0x578/0xc38 fs/quota/quota_tree.c:400 do_insert_tree+0x794/0xc38 fs/quota/quota_tree.c:402 do_insert_tree+0x794/0xc38 fs/quota/quota_tree.c:402 do_insert_tree+0x794/0xc38 fs/quota/quota_tree.c:402 dq_insert_tree fs/quota/quota_tree.c:432 [inline] qtree_write_dquot+0x3bc/0x4c8 fs/quota/quota_tree.c:451 v2_write_dquot+0xf0/0x180 fs/quota/quota_v2.c:361 dquot_acquire+0x2a8/0x4e0 fs/quota/dquot.c:472 ext4_acquire_dquot+0x270/0x428 fs/ext4/super.c:6810 dqget+0x654/0xccc fs/quota/dquot.c:988 __dquot_initialize+0x2d4/0xa80 fs/quota/dquot.c:1517 dquot_initialize+0x24/0x34 fs/quota/dquot.c:1579 ext4_process_orphan+0x5c/0x2b4 fs/ext4/orphan.c:329 ext4_orphan_cleanup+0x908/0x104c fs/ext4/orphan.c:474 __ext4_fill_super fs/ext4/super.c:5535 [inline] ext4_fill_super+0x62f8/0x6788 fs/ext4/super.c:5666 get_tree_bdev+0x358/0x544 fs/super.c:1366 ext4_get_tree+0x28/0x38 fs/ext4/super.c:5696 vfs_get_tree+0x90/0x274 fs/super.c:1573 do_new_mount+0x228/0x810 fs/namespace.c:3058 path_mount+0x5b4/0xe78 fs/namespace.c:3388 do_mount fs/namespace.c:3401 [inline] __do_sys_mount fs/namespace.c:3609 [inline] __se_sys_mount fs/namespace.c:3586 [inline] __arm64_sys_mount+0x49c/0x584 fs/namespace.c:3586 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x138 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+0x64/0x304 kernel/locking/rwsem.c:1520 v2_read_dquot+0x4c/0x118 fs/quota/quota_v2.c:335 dquot_acquire+0x120/0x4e0 fs/quota/dquot.c:463 ext4_acquire_dquot+0x270/0x428 fs/ext4/super.c:6810 dqget+0x654/0xccc fs/quota/dquot.c:988 __dquot_initialize+0x2d4/0xa80 fs/quota/dquot.c:1517 dquot_initialize+0x24/0x34 fs/quota/dquot.c:1579 ext4_process_orphan+0x5c/0x2b4 fs/ext4/orphan.c:329 ext4_orphan_cleanup+0x908/0x104c fs/ext4/orphan.c:474 __ext4_fill_super fs/ext4/super.c:5535 [inline] ext4_fill_super+0x62f8/0x6788 fs/ext4/super.c:5666 get_tree_bdev+0x358/0x544 fs/super.c:1366 ext4_get_tree+0x28/0x38 fs/ext4/super.c:5696 vfs_get_tree+0x90/0x274 fs/super.c:1573 do_new_mount+0x228/0x810 fs/namespace.c:3058 path_mount+0x5b4/0xe78 fs/namespace.c:3388 do_mount fs/namespace.c:3401 [inline] __do_sys_mount fs/namespace.c:3609 [inline] __se_sys_mount fs/namespace.c:3586 [inline] __arm64_sys_mount+0x49c/0x584 fs/namespace.c:3586 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x138 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+0x293c/0x6544 kernel/locking/lockdep.c:5049 lock_acquire+0x20c/0x644 kernel/locking/lockdep.c:5662 __mutex_lock_common+0x190/0x1f38 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:6790 ext4_mark_dquot_dirty+0xe8/0x140 fs/ext4/super.c:6867 mark_dquot_dirty fs/quota/dquot.c:372 [inline] mark_all_dquot_dirty+0x108/0x424 fs/quota/dquot.c:412 __dquot_alloc_space+0x560/0xce8 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+0xd30/0x435c fs/ext4/mballoc.c:5727 ext4_ext_map_blocks+0x1018/0x559c fs/ext4/extents.c:4340 ext4_map_blocks+0x860/0x1770 fs/ext4/inode.c:679 _ext4_get_block+0x194/0x4c8 fs/ext4/inode.c:822 ext4_get_block+0x4c/0x60 fs/ext4/inode.c:839 ext4_block_write_begin+0x508/0x10f8 fs/ext4/inode.c:1124 ext4_write_begin+0x5ec/0x133c fs/ext4/ext4_jbd2.h:-1 ext4_da_write_begin+0x360/0x9d8 fs/ext4/inode.c:3000 generic_perform_write+0x230/0x4b0 mm/filemap.c:3846 ext4_buffered_write_iter+0x2c4/0x530 fs/ext4/file.c:285 ext4_file_write_iter+0x188/0x152c 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+0x5ac/0x7c4 fs/read_write.c:584 ksys_pwrite64 fs/read_write.c:699 [inline] __do_sys_pwrite64 fs/read_write.c:709 [inline] __se_sys_pwrite64 fs/read_write.c:706 [inline] __arm64_sys_pwrite64+0x170/0x200 fs/read_write.c:706 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x138 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 *** 4 locks held by syz.6.1033/10599: #0: ffff000104968460 (sb_writers#3){.+.+}-{0:0}, at: vfs_write+0x23c/0x7c4 fs/read_write.c:580 #1: ffff0001030bde48 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline] #1: ffff0001030bde48 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: ext4_buffered_write_iter+0x98/0x530 fs/ext4/file.c:279 #2: ffff0001030bdcd0 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_map_blocks+0x7c4/0x1770 fs/ext4/inode.c:672 #3: ffff80001538d648 (dquot_srcu){....}-{0:0}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:349 stack backtrace: CPU: 0 PID: 10599 Comm: syz.6.1033 Not tainted 6.1.142-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Call trace: dump_backtrace+0x1c8/0x1f4 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+0xf8/0x160 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+0x240/0x2d4 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+0x293c/0x6544 kernel/locking/lockdep.c:5049 lock_acquire+0x20c/0x644 kernel/locking/lockdep.c:5662 __mutex_lock_common+0x190/0x1f38 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:6790 ext4_mark_dquot_dirty+0xe8/0x140 fs/ext4/super.c:6867 mark_dquot_dirty fs/quota/dquot.c:372 [inline] mark_all_dquot_dirty+0x108/0x424 fs/quota/dquot.c:412 __dquot_alloc_space+0x560/0xce8 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+0xd30/0x435c fs/ext4/mballoc.c:5727 ext4_ext_map_blocks+0x1018/0x559c fs/ext4/extents.c:4340 ext4_map_blocks+0x860/0x1770 fs/ext4/inode.c:679 _ext4_get_block+0x194/0x4c8 fs/ext4/inode.c:822 ext4_get_block+0x4c/0x60 fs/ext4/inode.c:839 ext4_block_write_begin+0x508/0x10f8 fs/ext4/inode.c:1124 ext4_write_begin+0x5ec/0x133c fs/ext4/ext4_jbd2.h:-1 ext4_da_write_begin+0x360/0x9d8 fs/ext4/inode.c:3000 generic_perform_write+0x230/0x4b0 mm/filemap.c:3846 ext4_buffered_write_iter+0x2c4/0x530 fs/ext4/file.c:285 ext4_file_write_iter+0x188/0x152c 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+0x5ac/0x7c4 fs/read_write.c:584 ksys_pwrite64 fs/read_write.c:699 [inline] __do_sys_pwrite64 fs/read_write.c:709 [inline] __se_sys_pwrite64 fs/read_write.c:706 [inline] __arm64_sys_pwrite64+0x170/0x200 fs/read_write.c:706 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x138 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