====================================================== WARNING: possible circular locking dependency detected 6.1.0-rc5-syzkaller-32269-g9500fc6e9e60 #0 Not tainted ------------------------------------------------------ syz-executor.4/30618 is trying to acquire lock: ffff0000d3bca650 (sb_internal#2){.+.+}-{0:0}, at: btrfs_join_transaction+0x30/0x40 fs/btrfs/transaction.c:764 but task is already holding lock: ffff0000d3bca558 (sb_pagefaults#2){.+.+}-{0:0}, at: do_page_mkwrite+0x74/0x288 mm/memory.c:2978 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #5 (sb_pagefaults#2){.+.+}-{0:0}: percpu_down_read include/linux/percpu-rwsem.h:51 [inline] __sb_start_write include/linux/fs.h:1826 [inline] sb_start_pagefault include/linux/fs.h:1930 [inline] btrfs_page_mkwrite+0xb4/0x6fc fs/btrfs/inode.c:8415 do_page_mkwrite+0x74/0x288 mm/memory.c:2978 do_shared_fault mm/memory.c:4619 [inline] do_fault+0x274/0x550 mm/memory.c:4687 handle_pte_fault mm/memory.c:4955 [inline] __handle_mm_fault mm/memory.c:5097 [inline] handle_mm_fault+0x78c/0xa48 mm/memory.c:5218 __do_page_fault arch/arm64/mm/fault.c:512 [inline] do_page_fault+0x428/0x79c arch/arm64/mm/fault.c:612 do_translation_fault+0x78/0x194 arch/arm64/mm/fault.c:695 do_mem_abort+0x54/0x130 arch/arm64/mm/fault.c:831 el0_da+0x70/0x16c arch/arm64/kernel/entry-common.c:515 el0t_64_sync_handler+0xcc/0xf0 arch/arm64/kernel/entry-common.c:658 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:584 -> #4 (&mm->mmap_lock){++++}-{3:3}: __might_fault+0x7c/0xb4 mm/memory.c:5646 _copy_to_user include/linux/uaccess.h:143 [inline] copy_to_user include/linux/uaccess.h:169 [inline] btrfs_ioctl_get_subvol_rootref+0x3a8/0x4bc fs/btrfs/ioctl.c:3203 btrfs_ioctl+0xa08/0xa64 fs/btrfs/ioctl.c:5556 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+0xd0/0x140 fs/ioctl.c:856 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall arch/arm64/kernel/syscall.c:52 [inline] el0_svc_common+0x138/0x220 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x48/0x164 arch/arm64/kernel/syscall.c:206 el0_svc+0x58/0x150 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:584 -> #3 (btrfs-root-00){++++}-{3:3}: down_read_nested+0x64/0x84 kernel/locking/rwsem.c:1634 __btrfs_tree_read_lock fs/btrfs/locking.c:134 [inline] btrfs_tree_read_lock fs/btrfs/locking.c:140 [inline] btrfs_read_lock_root_node+0x13c/0x1c0 fs/btrfs/locking.c:279 btrfs_search_slot_get_root+0x8c/0x374 fs/btrfs/ctree.c:1665 btrfs_search_slot+0x1dc/0x107c fs/btrfs/ctree.c:1985 btrfs_del_root+0x50/0xd0 fs/btrfs/root-tree.c:317 btrfs_clear_free_space_tree+0x268/0x49c fs/btrfs/free-space-tree.c:1273 btrfs_start_pre_rw_mount+0x128/0x380 fs/btrfs/disk-io.c:3210 open_ctree+0xb70/0xdc8 fs/btrfs/disk-io.c:3792 btrfs_fill_super+0xc0/0x174 fs/btrfs/super.c:1461 btrfs_mount_root+0x4a4/0x558 fs/btrfs/super.c:1829 legacy_get_tree+0x30/0x74 fs/fs_context.c:610 vfs_get_tree+0x40/0x140 fs/super.c:1531 fc_mount fs/namespace.c:1043 [inline] vfs_kern_mount+0xe0/0x140 fs/namespace.c:1073 btrfs_mount+0x20c/0x5e8 fs/btrfs/super.c:1889 legacy_get_tree+0x30/0x74 fs/fs_context.c:610 vfs_get_tree+0x40/0x140 fs/super.c:1531 do_new_mount+0x1dc/0x4e4 fs/namespace.c:3040 path_mount+0x358/0x890 fs/namespace.c:3370 do_mount fs/namespace.c:3383 [inline] __do_sys_mount fs/namespace.c:3591 [inline] __se_sys_mount fs/namespace.c:3568 [inline] __arm64_sys_mount+0x2c4/0x3c4 fs/namespace.c:3568 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall arch/arm64/kernel/syscall.c:52 [inline] el0_svc_common+0x138/0x220 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x48/0x164 arch/arm64/kernel/syscall.c:206 el0_svc+0x58/0x150 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:584 -> #2 (btrfs_trans_num_extwriters){++++}-{0:0}: join_transaction+0x10c/0x65c fs/btrfs/transaction.c:299 start_transaction+0x460/0x944 fs/btrfs/transaction.c:658 btrfs_join_transaction+0x30/0x40 fs/btrfs/transaction.c:764 btrfs_commit_super+0x64/0xa0 fs/btrfs/disk-io.c:4496 close_ctree+0x1dc/0x60c fs/btrfs/disk-io.c:4653 btrfs_put_super+0x20/0x30 fs/btrfs/super.c:394 generic_shutdown_super+0x94/0x198 fs/super.c:492 kill_anon_super+0x24/0x44 fs/super.c:1086 btrfs_kill_super+0x24/0x3c fs/btrfs/super.c:2441 deactivate_locked_super+0x70/0xe8 fs/super.c:332 deactivate_super+0xd0/0xd4 fs/super.c:363 cleanup_mnt+0x184/0x1c0 fs/namespace.c:1186 __cleanup_mnt+0x20/0x30 fs/namespace.c:1193 task_work_run+0x100/0x148 kernel/task_work.c:179 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] do_notify_resume+0x174/0x1f0 arch/arm64/kernel/signal.c:1127 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+0x9c/0x150 arch/arm64/kernel/entry-common.c:638 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:584 -> #1 (btrfs_trans_num_writers){++++}-{0:0}: join_transaction+0xe8/0x65c fs/btrfs/transaction.c:298 start_transaction+0x460/0x944 fs/btrfs/transaction.c:658 btrfs_join_transaction+0x30/0x40 fs/btrfs/transaction.c:764 btrfs_commit_super+0x64/0xa0 fs/btrfs/disk-io.c:4496 close_ctree+0x1dc/0x60c fs/btrfs/disk-io.c:4653 btrfs_put_super+0x20/0x30 fs/btrfs/super.c:394 generic_shutdown_super+0x94/0x198 fs/super.c:492 kill_anon_super+0x24/0x44 fs/super.c:1086 btrfs_kill_super+0x24/0x3c fs/btrfs/super.c:2441 deactivate_locked_super+0x70/0xe8 fs/super.c:332 deactivate_super+0xd0/0xd4 fs/super.c:363 cleanup_mnt+0x184/0x1c0 fs/namespace.c:1186 __cleanup_mnt+0x20/0x30 fs/namespace.c:1193 task_work_run+0x100/0x148 kernel/task_work.c:179 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] do_notify_resume+0x174/0x1f0 arch/arm64/kernel/signal.c:1127 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+0x9c/0x150 arch/arm64/kernel/entry-common.c:638 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:584 -> #0 (sb_internal#2){.+.+}-{0:0}: check_prev_add kernel/locking/lockdep.c:3097 [inline] check_prevs_add kernel/locking/lockdep.c:3216 [inline] validate_chain kernel/locking/lockdep.c:3831 [inline] __lock_acquire+0x1530/0x3084 kernel/locking/lockdep.c:5055 lock_acquire+0x100/0x1f8 kernel/locking/lockdep.c:5668 percpu_down_read include/linux/percpu-rwsem.h:51 [inline] __sb_start_write include/linux/fs.h:1826 [inline] sb_start_intwrite include/linux/fs.h:1948 [inline] start_transaction+0x360/0x944 fs/btrfs/transaction.c:652 btrfs_join_transaction+0x30/0x40 fs/btrfs/transaction.c:764 btrfs_dirty_inode+0x4c/0x13c fs/btrfs/inode.c:6085 btrfs_update_time+0x120/0x138 fs/btrfs/inode.c:6127 inode_update_time fs/inode.c:1871 [inline] __file_update_time fs/inode.c:2088 [inline] file_update_time+0x194/0x2c0 fs/inode.c:2119 btrfs_page_mkwrite+0x204/0x6fc fs/btrfs/inode.c:8431 do_page_mkwrite+0x74/0x288 mm/memory.c:2978 do_shared_fault mm/memory.c:4619 [inline] do_fault+0x274/0x550 mm/memory.c:4687 handle_pte_fault mm/memory.c:4955 [inline] __handle_mm_fault mm/memory.c:5097 [inline] handle_mm_fault+0x78c/0xa48 mm/memory.c:5218 __do_page_fault arch/arm64/mm/fault.c:512 [inline] do_page_fault+0x428/0x79c arch/arm64/mm/fault.c:612 do_translation_fault+0x78/0x194 arch/arm64/mm/fault.c:695 do_mem_abort+0x54/0x130 arch/arm64/mm/fault.c:831 el0_da+0x70/0x16c arch/arm64/kernel/entry-common.c:515 el0t_64_sync_handler+0xcc/0xf0 arch/arm64/kernel/entry-common.c:658 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:584 other info that might help us debug this: Chain exists of: sb_internal#2 --> &mm->mmap_lock --> sb_pagefaults#2 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(sb_pagefaults#2); lock(&mm->mmap_lock); lock(sb_pagefaults#2); lock(sb_internal#2); *** DEADLOCK *** 2 locks held by syz-executor.4/30618: #0: ffff0000c0e15648 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_lock include/linux/mmap_lock.h:117 [inline] #0: ffff0000c0e15648 (&mm->mmap_lock){++++}-{3:3}, at: do_page_fault+0x3c8/0x79c arch/arm64/mm/fault.c:597 #1: ffff0000d3bca558 (sb_pagefaults#2){.+.+}-{0:0}, at: do_page_mkwrite+0x74/0x288 mm/memory.c:2978 stack backtrace: CPU: 0 PID: 30618 Comm: syz-executor.4 Not tainted 6.1.0-rc5-syzkaller-32269-g9500fc6e9e60 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/30/2022 Call trace: dump_backtrace+0x1c4/0x1f0 arch/arm64/kernel/stacktrace.c:156 show_stack+0x2c/0x54 arch/arm64/kernel/stacktrace.c:163 __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x104/0x16c lib/dump_stack.c:106 dump_stack+0x1c/0x58 lib/dump_stack.c:113 print_circular_bug+0x2c4/0x2c8 kernel/locking/lockdep.c:2055 check_noncircular+0x14c/0x154 kernel/locking/lockdep.c:2177 check_prev_add kernel/locking/lockdep.c:3097 [inline] check_prevs_add kernel/locking/lockdep.c:3216 [inline] validate_chain kernel/locking/lockdep.c:3831 [inline] __lock_acquire+0x1530/0x3084 kernel/locking/lockdep.c:5055 lock_acquire+0x100/0x1f8 kernel/locking/lockdep.c:5668 percpu_down_read include/linux/percpu-rwsem.h:51 [inline] __sb_start_write include/linux/fs.h:1826 [inline] sb_start_intwrite include/linux/fs.h:1948 [inline] start_transaction+0x360/0x944 fs/btrfs/transaction.c:652 btrfs_join_transaction+0x30/0x40 fs/btrfs/transaction.c:764 btrfs_dirty_inode+0x4c/0x13c fs/btrfs/inode.c:6085 btrfs_update_time+0x120/0x138 fs/btrfs/inode.c:6127 inode_update_time fs/inode.c:1871 [inline] __file_update_time fs/inode.c:2088 [inline] file_update_time+0x194/0x2c0 fs/inode.c:2119 btrfs_page_mkwrite+0x204/0x6fc fs/btrfs/inode.c:8431 do_page_mkwrite+0x74/0x288 mm/memory.c:2978 do_shared_fault mm/memory.c:4619 [inline] do_fault+0x274/0x550 mm/memory.c:4687 handle_pte_fault mm/memory.c:4955 [inline] __handle_mm_fault mm/memory.c:5097 [inline] handle_mm_fault+0x78c/0xa48 mm/memory.c:5218 __do_page_fault arch/arm64/mm/fault.c:512 [inline] do_page_fault+0x428/0x79c arch/arm64/mm/fault.c:612 do_translation_fault+0x78/0x194 arch/arm64/mm/fault.c:695 do_mem_abort+0x54/0x130 arch/arm64/mm/fault.c:831 el0_da+0x70/0x16c arch/arm64/kernel/entry-common.c:515 el0t_64_sync_handler+0xcc/0xf0 arch/arm64/kernel/entry-common.c:658 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:584