====================================================== WARNING: possible circular locking dependency detected 6.1.140-syzkaller #0 Not tainted ------------------------------------------------------ syz.4.546/7060 is trying to acquire lock: ffff0000f102c650 (sb_internal#3){.+.+}-{0:0}, at: btrfs_join_transaction+0x30/0x40 fs/btrfs/transaction.c:780 but task is already holding lock: ffff0000f102c558 (sb_pagefaults#4){.+.+}-{0:0}, at: do_page_mkwrite+0x13c/0x358 mm/memory.c:3011 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #7 (sb_pagefaults#4){.+.+}-{0:0}: percpu_down_read include/linux/percpu-rwsem.h:51 [inline] __sb_start_write include/linux/fs.h:1891 [inline] sb_start_pagefault include/linux/fs.h:1995 [inline] btrfs_page_mkwrite+0x194/0xb78 fs/btrfs/inode.c:8583 do_page_mkwrite+0x13c/0x358 mm/memory.c:3011 do_shared_fault mm/memory.c:4696 [inline] do_fault mm/memory.c:4764 [inline] handle_pte_fault mm/memory.c:5031 [inline] __handle_mm_fault mm/memory.c:5173 [inline] handle_mm_fault+0x121c/0x2fd4 mm/memory.c:5294 __do_page_fault arch/arm64/mm/fault.c:499 [inline] do_page_fault+0x310/0x99c arch/arm64/mm/fault.c:583 do_translation_fault+0x94/0xc8 arch/arm64/mm/fault.c:667 do_mem_abort+0x70/0x194 arch/arm64/mm/fault.c:803 el1_abort+0x3c/0x5c arch/arm64/kernel/entry-common.c:367 el1h_64_sync_handler+0x80/0xcc arch/arm64/kernel/entry-common.c:427 el1h_64_sync+0x64/0x68 arch/arm64/kernel/entry.S:580 __arch_copy_to_user+0x190/0x234 arch/arm64/lib/copy_template.S:158 copy_page_to_iter+0x228/0x354 lib/iov_iter.c:725 copy_folio_to_iter include/linux/uio.h:172 [inline] filemap_read+0x17b0/0x1fd8 mm/filemap.c:2819 btrfs_file_read_iter+0x240/0x5d0 fs/btrfs/file.c:3840 call_read_iter include/linux/fs.h:2259 [inline] new_sync_read fs/read_write.c:389 [inline] vfs_read+0x5ac/0x7c4 fs/read_write.c:470 ksys_read+0x120/0x210 fs/read_write.c:613 __do_sys_read fs/read_write.c:623 [inline] __se_sys_read fs/read_write.c:621 [inline] __arm64_sys_read+0x7c/0x90 fs/read_write.c:621 __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 -> #6 (&mm->mmap_lock){++++}-{3:3}: __might_fault+0xc4/0x124 mm/memory.c:5852 filldir64+0x2cc/0x8fc fs/readdir.c:335 dir_emit include/linux/fs.h:3695 [inline] call_filldir fs/ext4/dir.c:547 [inline] ext4_dx_readdir fs/ext4/dir.c:623 [inline] ext4_readdir+0x2758/0x2f34 fs/ext4/dir.c:145 iterate_dir+0x1f0/0x4cc fs/readdir.c:-1 __do_sys_getdents64 fs/readdir.c:369 [inline] __se_sys_getdents64 fs/readdir.c:354 [inline] __arm64_sys_getdents64+0x11c/0x318 fs/readdir.c:354 __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 -> #5 (&type->i_mutex_dir_key#3){++++}-{3:3}: down_read+0x64/0x304 kernel/locking/rwsem.c:1520 inode_lock_shared include/linux/fs.h:768 [inline] lookup_slow+0x4c/0x80 fs/namei.c:1706 walk_component+0x270/0x364 fs/namei.c:1998 lookup_last fs/namei.c:2455 [inline] path_lookupat+0x13c/0x3d0 fs/namei.c:2479 filename_lookup+0x190/0x42c fs/namei.c:2508 kern_path+0x48/0x6c fs/namei.c:2606 is_same_device fs/btrfs/volumes.c:695 [inline] device_list_add+0x1208/0x1be0 fs/btrfs/volumes.c:928 btrfs_scan_one_device+0x364/0x570 fs/btrfs/volumes.c:1461 btrfs_control_ioctl+0x13c/0x33c fs/btrfs/super.c:2518 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl fs/ioctl.c:856 [inline] __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:856 __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 -> #4 (&fs_devs->device_list_mutex){+.+.}-{3:3}: __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 btrfs_run_dev_stats+0xf0/0xd00 fs/btrfs/volumes.c:8058 commit_cowonly_roots+0x16c/0x714 fs/btrfs/transaction.c:1297 btrfs_commit_transaction+0x10bc/0x29f0 fs/btrfs/transaction.c:2427 btrfs_sync_fs+0x530/0xa30 fs/btrfs/super.c:1535 sync_filesystem+0x1a0/0x218 fs/sync.c:66 generic_shutdown_super+0x70/0x324 fs/super.c:474 kill_anon_super+0x4c/0x80 fs/super.c:1128 btrfs_kill_super+0x40/0x58 fs/btrfs/super.c:2448 deactivate_locked_super+0xac/0x124 fs/super.c:332 deactivate_super+0xe8/0x108 fs/super.c:363 cleanup_mnt+0x37c/0x404 fs/namespace.c:1186 __cleanup_mnt+0x20/0x30 fs/namespace.c:1193 task_work_run+0x1ec/0x270 kernel/task_work.c:203 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] do_notify_resume+0x1f70/0x2b0c arch/arm64/kernel/signal.c:1137 prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:137 [inline] exit_to_user_mode arch/arm64/kernel/entry-common.c:142 [inline] el0_svc+0x98/0x138 arch/arm64/kernel/entry-common.c:638 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585 -> #3 (&fs_info->reloc_mutex){+.+.}-{3:3}: __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 btrfs_record_root_in_trans fs/btrfs/transaction.c:488 [inline] start_transaction+0x434/0x104c fs/btrfs/transaction.c:730 btrfs_start_transaction+0x34/0x44 fs/btrfs/transaction.c:766 btrfs_create_common+0x13c/0x224 fs/btrfs/inode.c:6782 btrfs_create+0x104/0x128 fs/btrfs/inode.c:6828 lookup_open fs/namei.c:3482 [inline] open_last_lookups fs/namei.c:3550 [inline] path_openat+0x112c/0x2680 fs/namei.c:3780 do_filp_open+0x174/0x344 fs/namei.c:3810 do_sys_openat2+0x128/0x3d8 fs/open.c:1318 do_sys_open fs/open.c:1334 [inline] __do_sys_openat fs/open.c:1350 [inline] __se_sys_openat fs/open.c:1345 [inline] __arm64_sys_openat+0x120/0x154 fs/open.c:1345 __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 -> #2 (btrfs_trans_num_extwriters){++++}-{0:0}: join_transaction+0x180/0xb6c fs/btrfs/transaction.c:303 start_transaction+0x854/0x104c fs/btrfs/transaction.c:667 btrfs_start_transaction+0x34/0x44 fs/btrfs/transaction.c:766 btrfs_create_common+0x13c/0x224 fs/btrfs/inode.c:6782 btrfs_create+0x104/0x128 fs/btrfs/inode.c:6828 lookup_open fs/namei.c:3482 [inline] open_last_lookups fs/namei.c:3550 [inline] path_openat+0x112c/0x2680 fs/namei.c:3780 do_filp_open+0x174/0x344 fs/namei.c:3810 do_sys_openat2+0x128/0x3d8 fs/open.c:1318 do_sys_open fs/open.c:1334 [inline] __do_sys_openat fs/open.c:1350 [inline] __se_sys_openat fs/open.c:1345 [inline] __arm64_sys_openat+0x120/0x154 fs/open.c:1345 __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 (btrfs_trans_num_writers){++++}-{0:0}: join_transaction+0x154/0xb6c fs/btrfs/transaction.c:302 start_transaction+0x854/0x104c fs/btrfs/transaction.c:667 btrfs_start_transaction+0x34/0x44 fs/btrfs/transaction.c:766 btrfs_create_common+0x13c/0x224 fs/btrfs/inode.c:6782 btrfs_create+0x104/0x128 fs/btrfs/inode.c:6828 lookup_open fs/namei.c:3482 [inline] open_last_lookups fs/namei.c:3550 [inline] path_openat+0x112c/0x2680 fs/namei.c:3780 do_filp_open+0x174/0x344 fs/namei.c:3810 do_sys_openat2+0x128/0x3d8 fs/open.c:1318 do_sys_open fs/open.c:1334 [inline] __do_sys_openat fs/open.c:1350 [inline] __se_sys_openat fs/open.c:1345 [inline] __arm64_sys_openat+0x120/0x154 fs/open.c:1345 __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 (sb_internal#3){.+.+}-{0:0}: 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 percpu_down_read include/linux/percpu-rwsem.h:51 [inline] __sb_start_write include/linux/fs.h:1891 [inline] sb_start_intwrite include/linux/fs.h:2013 [inline] start_transaction+0x5c4/0x104c fs/btrfs/transaction.c:661 btrfs_join_transaction+0x30/0x40 fs/btrfs/transaction.c:780 btrfs_dirty_inode+0xb4/0x1c0 fs/btrfs/inode.c:6274 btrfs_update_time+0x170/0x18c fs/btrfs/inode.c:6316 inode_update_time fs/inode.c:1958 [inline] __file_update_time+0xc0/0x220 fs/inode.c:2147 file_update_time+0x26c/0x2e0 fs/inode.c:2178 btrfs_page_mkwrite+0x394/0xb78 fs/btrfs/inode.c:8599 do_page_mkwrite+0x13c/0x358 mm/memory.c:3011 do_shared_fault mm/memory.c:4696 [inline] do_fault mm/memory.c:4764 [inline] handle_pte_fault mm/memory.c:5031 [inline] __handle_mm_fault mm/memory.c:5173 [inline] handle_mm_fault+0x121c/0x2fd4 mm/memory.c:5294 __do_page_fault arch/arm64/mm/fault.c:499 [inline] do_page_fault+0x310/0x99c arch/arm64/mm/fault.c:583 do_translation_fault+0x94/0xc8 arch/arm64/mm/fault.c:667 do_mem_abort+0x70/0x194 arch/arm64/mm/fault.c:803 el1_abort+0x3c/0x5c arch/arm64/kernel/entry-common.c:367 el1h_64_sync_handler+0x80/0xcc arch/arm64/kernel/entry-common.c:427 el1h_64_sync+0x64/0x68 arch/arm64/kernel/entry.S:580 __arch_copy_to_user+0x190/0x234 arch/arm64/lib/copy_template.S:158 copy_page_to_iter+0x228/0x354 lib/iov_iter.c:725 copy_folio_to_iter include/linux/uio.h:172 [inline] filemap_read+0x17b0/0x1fd8 mm/filemap.c:2819 btrfs_file_read_iter+0x240/0x5d0 fs/btrfs/file.c:3840 call_read_iter include/linux/fs.h:2259 [inline] new_sync_read fs/read_write.c:389 [inline] vfs_read+0x5ac/0x7c4 fs/read_write.c:470 ksys_read+0x120/0x210 fs/read_write.c:613 __do_sys_read fs/read_write.c:623 [inline] __se_sys_read fs/read_write.c:621 [inline] __arm64_sys_read+0x7c/0x90 fs/read_write.c:621 __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: sb_internal#3 --> &mm->mmap_lock --> sb_pagefaults#4 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(sb_pagefaults#4); lock(&mm->mmap_lock); lock(sb_pagefaults#4); lock(sb_internal#3); *** DEADLOCK *** 3 locks held by syz.4.546/7060: #0: ffff0000d530e868 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x114/0x16c fs/file.c:1040 #1: ffff0000d6147948 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline] #1: ffff0000d6147948 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5322 [inline] #1: ffff0000d6147948 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x38/0x2e8 mm/memory.c:5384 #2: ffff0000f102c558 (sb_pagefaults#4){.+.+}-{0:0}, at: do_page_mkwrite+0x13c/0x358 mm/memory.c:3011 stack backtrace: CPU: 1 PID: 7060 Comm: syz.4.546 Not tainted 6.1.140-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 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 percpu_down_read include/linux/percpu-rwsem.h:51 [inline] __sb_start_write include/linux/fs.h:1891 [inline] sb_start_intwrite include/linux/fs.h:2013 [inline] start_transaction+0x5c4/0x104c fs/btrfs/transaction.c:661 btrfs_join_transaction+0x30/0x40 fs/btrfs/transaction.c:780 btrfs_dirty_inode+0xb4/0x1c0 fs/btrfs/inode.c:6274 btrfs_update_time+0x170/0x18c fs/btrfs/inode.c:6316 inode_update_time fs/inode.c:1958 [inline] __file_update_time+0xc0/0x220 fs/inode.c:2147 file_update_time+0x26c/0x2e0 fs/inode.c:2178 btrfs_page_mkwrite+0x394/0xb78 fs/btrfs/inode.c:8599 do_page_mkwrite+0x13c/0x358 mm/memory.c:3011 do_shared_fault mm/memory.c:4696 [inline] do_fault mm/memory.c:4764 [inline] handle_pte_fault mm/memory.c:5031 [inline] __handle_mm_fault mm/memory.c:5173 [inline] handle_mm_fault+0x121c/0x2fd4 mm/memory.c:5294 __do_page_fault arch/arm64/mm/fault.c:499 [inline] do_page_fault+0x310/0x99c arch/arm64/mm/fault.c:583 do_translation_fault+0x94/0xc8 arch/arm64/mm/fault.c:667 do_mem_abort+0x70/0x194 arch/arm64/mm/fault.c:803 el1_abort+0x3c/0x5c arch/arm64/kernel/entry-common.c:367 el1h_64_sync_handler+0x80/0xcc arch/arm64/kernel/entry-common.c:427 el1h_64_sync+0x64/0x68 arch/arm64/kernel/entry.S:580 __arch_copy_to_user+0x190/0x234 arch/arm64/lib/copy_template.S:158 copy_page_to_iter+0x228/0x354 lib/iov_iter.c:725 copy_folio_to_iter include/linux/uio.h:172 [inline] filemap_read+0x17b0/0x1fd8 mm/filemap.c:2819 btrfs_file_read_iter+0x240/0x5d0 fs/btrfs/file.c:3840 call_read_iter include/linux/fs.h:2259 [inline] new_sync_read fs/read_write.c:389 [inline] vfs_read+0x5ac/0x7c4 fs/read_write.c:470 ksys_read+0x120/0x210 fs/read_write.c:613 __do_sys_read fs/read_write.c:623 [inline] __se_sys_read fs/read_write.c:621 [inline] __arm64_sys_read+0x7c/0x90 fs/read_write.c:621 __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