====================================================== WARNING: possible circular locking dependency detected 6.1.0-rc5-syzkaller-00326-g77c51ba552a1 #0 Not tainted ------------------------------------------------------ syz-executor.4/12574 is trying to acquire lock: ffff88807ea82650 (sb_internal#2){.+.+}-{0:0}, at: btrfs_dirty_inode+0xf4/0x250 fs/btrfs/inode.c:6085 but task is already holding lock: ffff88807ea82558 (sb_pagefaults#3){.+.+}-{0:0}, at: do_page_mkwrite+0x19b/0x680 mm/memory.c:2978 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #6 (sb_pagefaults#3){.+.+}-{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+0x1b5/0x1140 fs/btrfs/inode.c:8415 do_page_mkwrite+0x19b/0x680 mm/memory.c:2978 do_shared_fault mm/memory.c:4619 [inline] do_fault mm/memory.c:4687 [inline] handle_pte_fault mm/memory.c:4955 [inline] __handle_mm_fault+0x2280/0x3a40 mm/memory.c:5097 handle_mm_fault+0x1cc/0x780 mm/memory.c:5218 do_user_addr_fault+0x475/0x1210 arch/x86/mm/fault.c:1428 handle_page_fault arch/x86/mm/fault.c:1519 [inline] exc_page_fault+0x98/0x170 arch/x86/mm/fault.c:1575 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:570 -> #5 (&mm->mmap_lock#2){++++}-{3:3}: __might_fault mm/memory.c:5646 [inline] __might_fault+0x10c/0x180 mm/memory.c:5639 _copy_to_user+0x29/0x150 lib/usercopy.c:29 copy_to_user include/linux/uaccess.h:169 [inline] btrfs_ioctl_get_subvol_rootref+0x74e/0xad0 fs/btrfs/ioctl.c:3203 btrfs_ioctl+0x2de6/0x5be0 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] __x64_sys_ioctl+0x197/0x210 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd -> #4 (btrfs-root-00){++++}-{3:3}: down_write_nested+0x98/0x220 kernel/locking/rwsem.c:1672 __btrfs_tree_lock+0x32/0x3d0 fs/btrfs/locking.c:196 btrfs_tree_lock fs/btrfs/locking.c:203 [inline] btrfs_lock_root_node+0x61/0x90 fs/btrfs/locking.c:256 commit_cowonly_roots+0x13c/0xa10 fs/btrfs/transaction.c:1266 btrfs_commit_transaction+0xb93/0x36e0 fs/btrfs/transaction.c:2376 btrfs_commit_super+0xc5/0x100 fs/btrfs/disk-io.c:4499 close_ctree+0x39c/0xdc7 fs/btrfs/disk-io.c:4653 generic_shutdown_super+0x158/0x410 fs/super.c:492 kill_anon_super+0x3a/0x60 fs/super.c:1086 btrfs_kill_super+0x3c/0x50 fs/btrfs/super.c:2441 deactivate_locked_super+0x98/0x160 fs/super.c:332 deactivate_super+0xb1/0xd0 fs/super.c:363 cleanup_mnt+0x2ae/0x3d0 fs/namespace.c:1186 task_work_run+0x16f/0x270 kernel/task_work.c:179 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop kernel/entry/common.c:171 [inline] exit_to_user_mode_prepare+0x23c/0x250 kernel/entry/common.c:203 __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline] syscall_exit_to_user_mode+0x1d/0x50 kernel/entry/common.c:296 do_syscall_64+0x46/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x63/0xcd -> #3 (&fs_info->reloc_mutex){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x12f/0x1360 kernel/locking/mutex.c:747 btrfs_record_root_in_trans+0x13d/0x1b0 fs/btrfs/transaction.c:484 start_transaction+0x295/0x1470 fs/btrfs/transaction.c:721 btrfs_create_common+0x1aa/0x260 fs/btrfs/inode.c:6633 btrfs_create+0x116/0x160 fs/btrfs/inode.c:6679 lookup_open.isra.0+0xf05/0x12a0 fs/namei.c:3413 open_last_lookups fs/namei.c:3481 [inline] path_openat+0x996/0x2860 fs/namei.c:3710 do_filp_open+0x1ba/0x410 fs/namei.c:3740 do_sys_openat2+0x16d/0x4c0 fs/open.c:1310 do_sys_open fs/open.c:1326 [inline] __do_sys_open fs/open.c:1334 [inline] __se_sys_open fs/open.c:1330 [inline] __x64_sys_open+0x11d/0x1c0 fs/open.c:1330 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd -> #2 (btrfs_trans_num_extwriters){++++}-{0:0}: join_transaction+0x1b3/0x10f0 fs/btrfs/transaction.c:299 start_transaction+0x407/0x1470 fs/btrfs/transaction.c:658 btrfs_commit_super+0x9d/0x100 fs/btrfs/disk-io.c:4496 close_ctree+0x39c/0xdc7 fs/btrfs/disk-io.c:4653 generic_shutdown_super+0x158/0x410 fs/super.c:492 kill_anon_super+0x3a/0x60 fs/super.c:1086 btrfs_kill_super+0x3c/0x50 fs/btrfs/super.c:2441 deactivate_locked_super+0x98/0x160 fs/super.c:332 deactivate_super+0xb1/0xd0 fs/super.c:363 cleanup_mnt+0x2ae/0x3d0 fs/namespace.c:1186 task_work_run+0x16f/0x270 kernel/task_work.c:179 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop kernel/entry/common.c:171 [inline] exit_to_user_mode_prepare+0x23c/0x250 kernel/entry/common.c:203 __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline] syscall_exit_to_user_mode+0x1d/0x50 kernel/entry/common.c:296 do_syscall_64+0x46/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x63/0xcd -> #1 (btrfs_trans_num_writers){++++}-{0:0}: join_transaction+0x18e/0x10f0 fs/btrfs/transaction.c:298 start_transaction+0x407/0x1470 fs/btrfs/transaction.c:658 btrfs_commit_super+0x9d/0x100 fs/btrfs/disk-io.c:4496 close_ctree+0x39c/0xdc7 fs/btrfs/disk-io.c:4653 generic_shutdown_super+0x158/0x410 fs/super.c:492 kill_anon_super+0x3a/0x60 fs/super.c:1086 btrfs_kill_super+0x3c/0x50 fs/btrfs/super.c:2441 deactivate_locked_super+0x98/0x160 fs/super.c:332 deactivate_super+0xb1/0xd0 fs/super.c:363 cleanup_mnt+0x2ae/0x3d0 fs/namespace.c:1186 task_work_run+0x16f/0x270 kernel/task_work.c:179 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop kernel/entry/common.c:171 [inline] exit_to_user_mode_prepare+0x23c/0x250 kernel/entry/common.c:203 __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline] syscall_exit_to_user_mode+0x1d/0x50 kernel/entry/common.c:296 do_syscall_64+0x46/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x63/0xcd -> #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+0x2a43/0x56d0 kernel/locking/lockdep.c:5055 lock_acquire kernel/locking/lockdep.c:5668 [inline] lock_acquire+0x1e3/0x630 kernel/locking/lockdep.c:5633 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+0x878/0x1470 fs/btrfs/transaction.c:652 btrfs_dirty_inode+0xf4/0x250 fs/btrfs/inode.c:6085 btrfs_update_time+0x25a/0x2c0 fs/btrfs/inode.c:6127 inode_update_time fs/inode.c:1871 [inline] __file_update_time fs/inode.c:2088 [inline] file_update_time+0x1fb/0x270 fs/inode.c:2119 btrfs_page_mkwrite+0x4f1/0x1140 fs/btrfs/inode.c:8431 do_page_mkwrite+0x19b/0x680 mm/memory.c:2978 do_shared_fault mm/memory.c:4619 [inline] do_fault mm/memory.c:4687 [inline] handle_pte_fault mm/memory.c:4955 [inline] __handle_mm_fault+0x2280/0x3a40 mm/memory.c:5097 handle_mm_fault+0x1cc/0x780 mm/memory.c:5218 do_user_addr_fault+0x475/0x1210 arch/x86/mm/fault.c:1428 handle_page_fault arch/x86/mm/fault.c:1519 [inline] exc_page_fault+0x98/0x170 arch/x86/mm/fault.c:1575 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:570 other info that might help us debug this: Chain exists of: sb_internal#2 --> &mm->mmap_lock#2 --> sb_pagefaults#3 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(sb_pagefaults#3); lock(&mm->mmap_lock#2); lock(sb_pagefaults#3); lock(sb_internal#2); *** DEADLOCK *** 2 locks held by syz-executor.4/12574: #0: ffff88807c937558 (&mm->mmap_lock#2){++++}-{3:3}, at: mmap_read_lock include/linux/mmap_lock.h:117 [inline] #0: ffff88807c937558 (&mm->mmap_lock#2){++++}-{3:3}, at: do_user_addr_fault+0xa51/0x1210 arch/x86/mm/fault.c:1379 #1: ffff88807ea82558 (sb_pagefaults#3){.+.+}-{0:0}, at: do_page_mkwrite+0x19b/0x680 mm/memory.c:2978 stack backtrace: CPU: 1 PID: 12574 Comm: syz-executor.4 Not tainted 6.1.0-rc5-syzkaller-00326-g77c51ba552a1 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd1/0x138 lib/dump_stack.c:106 check_noncircular+0x25f/0x2e0 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+0x2a43/0x56d0 kernel/locking/lockdep.c:5055 lock_acquire kernel/locking/lockdep.c:5668 [inline] lock_acquire+0x1e3/0x630 kernel/locking/lockdep.c:5633 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+0x878/0x1470 fs/btrfs/transaction.c:652 btrfs_dirty_inode+0xf4/0x250 fs/btrfs/inode.c:6085 btrfs_update_time+0x25a/0x2c0 fs/btrfs/inode.c:6127 inode_update_time fs/inode.c:1871 [inline] __file_update_time fs/inode.c:2088 [inline] file_update_time+0x1fb/0x270 fs/inode.c:2119 btrfs_page_mkwrite+0x4f1/0x1140 fs/btrfs/inode.c:8431 do_page_mkwrite+0x19b/0x680 mm/memory.c:2978 do_shared_fault mm/memory.c:4619 [inline] do_fault mm/memory.c:4687 [inline] handle_pte_fault mm/memory.c:4955 [inline] __handle_mm_fault+0x2280/0x3a40 mm/memory.c:5097 handle_mm_fault+0x1cc/0x780 mm/memory.c:5218 do_user_addr_fault+0x475/0x1210 arch/x86/mm/fault.c:1428 handle_page_fault arch/x86/mm/fault.c:1519 [inline] exc_page_fault+0x98/0x170 arch/x86/mm/fault.c:1575 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:570 RIP: 0033:0x7fdf2c22b1b9 Code: 48 8b 04 24 48 85 c0 74 17 48 8b 54 24 18 48 0f ca 48 89 54 24 18 48 83 f8 01 0f 85 9b 02 00 00 48 8b 44 24 10 48 8b 54 24 18 <48> 89 10 e9 c2 fd ff ff 48 8b 44 24 10 0f b7 10 48 8b 04 24 48 85 RSP: 002b:00007ffeaf364a40 EFLAGS: 00010246 RAX: 0000000020000100 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000020000000 RSI: 0000000000000000 RDI: 0000555555e9c2e8 RBP: 00007ffeaf364b38 R08: 0000000000000000 R09: 0000000000000000 R10: 00007fdf2be131a8 R11: 0000000000000246 R12: 000000000007de2a R13: 00007ffeaf364b60 R14: 00007fdf2c3abf80 R15: 0000000000000032