BTRFS info (device loop7): force clearing of disk cache BTRFS info (device loop7): enabling auto defrag BTRFS info (device loop7): max_inline set to 0 ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.7.419/9286 is trying to acquire lock: ffff0000c1844188 (&root->kernfs_rwsem){++++}-{4:4}, at: kernfs_add_one+0x48/0x60c fs/kernfs/dir.c:791 but task is already holding lock: ffff0000cf4fd998 (&fs_info->qgroup_ioctl_lock){+.+.}-{4:4}, at: btrfs_quota_enable+0x1cc/0x2438 fs/btrfs/qgroup.c:1018 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #5 (&fs_info->qgroup_ioctl_lock){+.+.}-{4:4}: __mutex_lock_common+0x1d0/0x2678 kernel/locking/mutex.c:598 __mutex_lock kernel/locking/mutex.c:760 [inline] mutex_lock_nested+0x2c/0x38 kernel/locking/mutex.c:812 btrfs_create_qgroup+0x60/0x46c fs/btrfs/qgroup.c:1668 create_pending_snapshot+0x6c4/0x2d6c fs/btrfs/transaction.c:1732 create_pending_snapshots+0x150/0x198 fs/btrfs/transaction.c:1924 btrfs_commit_transaction+0x1000/0x2ce4 fs/btrfs/transaction.c:2412 create_snapshot+0x588/0x9fc fs/btrfs/ioctl.c:782 btrfs_mksubvol+0x43c/0x5a4 fs/btrfs/ioctl.c:934 btrfs_mksnapshot+0xb4/0x140 fs/btrfs/ioctl.c:978 __btrfs_ioctl_snap_create+0x404/0x5b8 fs/btrfs/ioctl.c:1242 btrfs_ioctl_snap_create+0x138/0x178 fs/btrfs/ioctl.c:1269 btrfs_ioctl+0x4b0/0xc3c fs/btrfs/ioctl.c:-1 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __arm64_sys_ioctl+0x14c/0x1c4 fs/ioctl.c:583 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x5c/0x254 arch/arm64/kernel/entry-common.c:724 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:743 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596 -> #4 (&fs_info->reloc_mutex){+.+.}-{4:4}: __mutex_lock_common+0x1d0/0x2678 kernel/locking/mutex.c:598 __mutex_lock kernel/locking/mutex.c:760 [inline] mutex_lock_nested+0x2c/0x38 kernel/locking/mutex.c:812 btrfs_record_root_in_trans fs/btrfs/transaction.c:503 [inline] start_transaction+0x480/0x155c fs/btrfs/transaction.c:779 btrfs_start_transaction+0x34/0x44 fs/btrfs/transaction.c:816 btrfs_create_common+0x120/0x208 fs/btrfs/inode.c:6786 btrfs_create+0x104/0x128 fs/btrfs/inode.c:6832 lookup_open fs/namei.c:3796 [inline] open_last_lookups fs/namei.c:3895 [inline] path_openat+0x12d8/0x2c40 fs/namei.c:4131 do_filp_open+0x18c/0x36c fs/namei.c:4161 do_sys_openat2+0x11c/0x1b4 fs/open.c:1437 do_sys_open fs/open.c:1452 [inline] __do_sys_openat fs/open.c:1468 [inline] __se_sys_openat fs/open.c:1463 [inline] __arm64_sys_openat+0x120/0x158 fs/open.c:1463 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x5c/0x254 arch/arm64/kernel/entry-common.c:724 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:743 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596 -> #3 (btrfs_trans_num_extwriters){++++}-{0:0}: join_transaction+0x190/0xb5c fs/btrfs/transaction.c:321 start_transaction+0x778/0x155c fs/btrfs/transaction.c:705 btrfs_start_transaction+0x34/0x44 fs/btrfs/transaction.c:816 btrfs_rebuild_free_space_tree+0xac/0x6c0 fs/btrfs/free-space-tree.c:1340 btrfs_start_pre_rw_mount+0xed8/0x1728 fs/btrfs/disk-io.c:3062 open_ctree+0x24cc/0x358c fs/btrfs/disk-io.c:3619 btrfs_fill_super fs/btrfs/super.c:987 [inline] btrfs_get_tree_super fs/btrfs/super.c:1951 [inline] btrfs_get_tree_subvol fs/btrfs/super.c:2094 [inline] btrfs_get_tree+0xd94/0x15dc fs/btrfs/super.c:2128 vfs_get_tree+0x90/0x28c fs/super.c:1751 fc_mount fs/namespace.c:1208 [inline] do_new_mount_fc fs/namespace.c:3651 [inline] do_new_mount+0x284/0x944 fs/namespace.c:3727 path_mount+0x5b4/0xdfc fs/namespace.c:4037 do_mount fs/namespace.c:4050 [inline] __do_sys_mount fs/namespace.c:4238 [inline] __se_sys_mount fs/namespace.c:4215 [inline] __arm64_sys_mount+0x3e8/0x468 fs/namespace.c:4215 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x5c/0x254 arch/arm64/kernel/entry-common.c:724 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:743 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596 -> #2 (btrfs_trans_num_writers){++++}-{0:0}: __lock_release kernel/locking/lockdep.c:5574 [inline] lock_release+0x198/0x39c kernel/locking/lockdep.c:5889 percpu_up_read include/linux/percpu-rwsem.h:112 [inline] __sb_end_write include/linux/fs.h:1911 [inline] sb_end_intwrite+0x3c/0x348 include/linux/fs.h:2028 __btrfs_end_transaction+0x1f4/0x5f4 fs/btrfs/transaction.c:1076 btrfs_end_transaction+0x24/0x34 fs/btrfs/transaction.c:1110 btrfs_dirty_inode+0x140/0x190 fs/btrfs/inode.c:6286 btrfs_update_time+0xa0/0xd0 fs/btrfs/inode.c:6306 inode_update_time fs/inode.c:2117 [inline] __file_update_time fs/inode.c:2345 [inline] file_update_time+0x2a4/0x3c0 fs/inode.c:2375 btrfs_page_mkwrite+0x580/0x1714 fs/btrfs/file.c:1915 do_page_mkwrite+0x138/0x2b8 mm/memory.c:3489 wp_page_shared mm/memory.c:3890 [inline] do_wp_page+0x1d30/0x4158 mm/memory.c:4109 handle_pte_fault mm/memory.c:6250 [inline] __handle_mm_fault+0xd78/0x4798 mm/memory.c:6366 handle_mm_fault+0x274/0x7fc mm/memory.c:6535 do_page_fault+0x548/0x13ec arch/arm64/mm/fault.c:700 do_mem_abort+0x70/0x194 arch/arm64/mm/fault.c:933 el1_abort+0x40/0x64 arch/arm64/kernel/entry-common.c:303 el1h_64_sync_handler+0x50/0xfc arch/arm64/kernel/entry-common.c:437 el1h_64_sync+0x6c/0x70 arch/arm64/kernel/entry.S:591 __uaccess_mask_ptr arch/arm64/include/asm/uaccess.h:169 [inline] filldir64+0x2d0/0x6bc fs/readdir.c:377 dir_emit_dot include/linux/fs.h:3990 [inline] dir_emit_dots include/linux/fs.h:4001 [inline] kernfs_fop_readdir+0x15c/0x79c fs/kernfs/dir.c:1889 iterate_dir+0x2dc/0x478 fs/readdir.c:108 __do_sys_getdents64 fs/readdir.c:410 [inline] __se_sys_getdents64 fs/readdir.c:396 [inline] __arm64_sys_getdents64+0x110/0x2fc fs/readdir.c:396 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x5c/0x254 arch/arm64/kernel/entry-common.c:724 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:743 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596 -> #1 (sb_pagefaults#5){.+.+}-{0:0}: percpu_down_read_internal include/linux/percpu-rwsem.h:53 [inline] percpu_down_read_freezable include/linux/percpu-rwsem.h:83 [inline] __sb_start_write include/linux/fs.h:1916 [inline] sb_start_pagefault include/linux/fs.h:2081 [inline] btrfs_page_mkwrite+0x284/0x1714 fs/btrfs/file.c:1874 do_page_mkwrite+0x138/0x2b8 mm/memory.c:3489 wp_page_shared mm/memory.c:3890 [inline] do_wp_page+0x1d30/0x4158 mm/memory.c:4109 handle_pte_fault mm/memory.c:6250 [inline] __handle_mm_fault+0xd78/0x4798 mm/memory.c:6366 handle_mm_fault+0x274/0x7fc mm/memory.c:6535 do_page_fault+0x548/0x13ec arch/arm64/mm/fault.c:700 do_mem_abort+0x70/0x194 arch/arm64/mm/fault.c:933 el1_abort+0x40/0x64 arch/arm64/kernel/entry-common.c:303 el1h_64_sync_handler+0x50/0xfc arch/arm64/kernel/entry-common.c:437 el1h_64_sync+0x6c/0x70 arch/arm64/kernel/entry.S:591 __uaccess_mask_ptr arch/arm64/include/asm/uaccess.h:169 [inline] filldir64+0x2ec/0x6bc fs/readdir.c:379 dir_emit include/linux/fs.h:3986 [inline] kernfs_fop_readdir+0x498/0x79c fs/kernfs/dir.c:1910 iterate_dir+0x2dc/0x478 fs/readdir.c:108 __do_sys_getdents64 fs/readdir.c:410 [inline] __se_sys_getdents64 fs/readdir.c:396 [inline] __arm64_sys_getdents64+0x110/0x2fc fs/readdir.c:396 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x5c/0x254 arch/arm64/kernel/entry-common.c:724 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:743 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596 -> #0 (&root->kernfs_rwsem){++++}-{4:4}: check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x1774/0x30a4 kernel/locking/lockdep.c:5237 lock_acquire+0x14c/0x2e0 kernel/locking/lockdep.c:5868 down_write+0x50/0xc0 kernel/locking/rwsem.c:1590 kernfs_add_one+0x48/0x60c fs/kernfs/dir.c:791 kernfs_create_dir_ns+0xd4/0x12c fs/kernfs/dir.c:1093 sysfs_create_dir_ns+0x114/0x24c fs/sysfs/dir.c:59 create_dir lib/kobject.c:73 [inline] kobject_add_internal+0x5a8/0xb20 lib/kobject.c:240 kobject_add_varg lib/kobject.c:374 [inline] kobject_init_and_add+0x118/0x17c lib/kobject.c:457 btrfs_sysfs_add_qgroups+0x110/0x268 fs/btrfs/sysfs.c:2645 btrfs_quota_enable+0x210/0x2438 fs/btrfs/qgroup.c:1022 btrfs_ioctl_quota_ctl+0x178/0x1bc fs/btrfs/ioctl.c:3667 btrfs_ioctl+0x86c/0xc3c fs/btrfs/ioctl.c:5333 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __arm64_sys_ioctl+0x14c/0x1c4 fs/ioctl.c:583 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x5c/0x254 arch/arm64/kernel/entry-common.c:724 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:743 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596 other info that might help us debug this: Chain exists of: &root->kernfs_rwsem --> &fs_info->reloc_mutex --> &fs_info->qgroup_ioctl_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&fs_info->qgroup_ioctl_lock); lock(&fs_info->reloc_mutex); lock(&fs_info->qgroup_ioctl_lock); lock(&root->kernfs_rwsem); *** DEADLOCK *** 3 locks held by syz.7.419/9286: #0: ffff0000c5ddc420 (sb_writers#17){.+.+}-{0:0}, at: mnt_want_write_file+0x64/0x1e8 fs/namespace.c:552 #1: ffff0000cf4fcc60 (&fs_info->subvol_sem){++++}-{4:4}, at: btrfs_ioctl_quota_ctl+0x16c/0x1bc fs/btrfs/ioctl.c:3666 #2: ffff0000cf4fd998 (&fs_info->qgroup_ioctl_lock){+.+.}-{4:4}, at: btrfs_quota_enable+0x1cc/0x2438 fs/btrfs/qgroup.c:1018 stack backtrace: CPU: 1 UID: 0 PID: 9286 Comm: syz.7.419 Not tainted syzkaller #0 PREEMPT Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/03/2025 Call trace: show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:499 (C) __dump_stack+0x30/0x40 lib/dump_stack.c:94 dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120 dump_stack+0x1c/0x28 lib/dump_stack.c:129 print_circular_bug+0x324/0x32c kernel/locking/lockdep.c:2043 check_noncircular+0x154/0x174 kernel/locking/lockdep.c:2175 check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x1774/0x30a4 kernel/locking/lockdep.c:5237 lock_acquire+0x14c/0x2e0 kernel/locking/lockdep.c:5868 down_write+0x50/0xc0 kernel/locking/rwsem.c:1590 kernfs_add_one+0x48/0x60c fs/kernfs/dir.c:791 kernfs_create_dir_ns+0xd4/0x12c fs/kernfs/dir.c:1093 sysfs_create_dir_ns+0x114/0x24c fs/sysfs/dir.c:59 create_dir lib/kobject.c:73 [inline] kobject_add_internal+0x5a8/0xb20 lib/kobject.c:240 kobject_add_varg lib/kobject.c:374 [inline] kobject_init_and_add+0x118/0x17c lib/kobject.c:457 btrfs_sysfs_add_qgroups+0x110/0x268 fs/btrfs/sysfs.c:2645 btrfs_quota_enable+0x210/0x2438 fs/btrfs/qgroup.c:1022 btrfs_ioctl_quota_ctl+0x178/0x1bc fs/btrfs/ioctl.c:3667 btrfs_ioctl+0x86c/0xc3c fs/btrfs/ioctl.c:5333 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __arm64_sys_ioctl+0x14c/0x1c4 fs/ioctl.c:583 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x5c/0x254 arch/arm64/kernel/entry-common.c:724 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:743 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596