====================================================== WARNING: possible circular locking dependency detected 6.1.0-rc6-syzkaller-00176-g08ad43d554ba #0 Not tainted ------------------------------------------------------ syz-executor539/3633 is trying to acquire lock: ffff8880217524d8 (btrfs-root-00){.+.+}-{3:3}, at: __btrfs_tree_read_lock fs/btrfs/locking.c:134 [inline] ffff8880217524d8 (btrfs-root-00){.+.+}-{3:3}, at: btrfs_tree_read_lock fs/btrfs/locking.c:140 [inline] ffff8880217524d8 (btrfs-root-00){.+.+}-{3:3}, at: btrfs_read_lock_root_node+0x2b4/0x400 fs/btrfs/locking.c:279 but task is already holding lock: ffff88807cebccc0 (&fs_info->reloc_mutex){+.+.}-{3:3}, at: btrfs_commit_transaction+0x13e8/0x3760 fs/btrfs/transaction.c:2316 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #5 (&fs_info->reloc_mutex){+.+.}-{3:3}: lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5668 __mutex_lock_common+0x1bd/0x26e0 kernel/locking/mutex.c:603 __mutex_lock kernel/locking/mutex.c:747 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:799 btrfs_record_root_in_trans+0x153/0x180 fs/btrfs/transaction.c:484 start_transaction+0x3af/0x1180 fs/btrfs/transaction.c:721 btrfs_create_common+0x2c6/0x420 fs/btrfs/inode.c:6633 lookup_open fs/namei.c:3413 [inline] open_last_lookups fs/namei.c:3481 [inline] path_openat+0x12d0/0x2df0 fs/namei.c:3710 do_filp_open+0x264/0x4f0 fs/namei.c:3740 do_sys_openat2+0x124/0x4e0 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+0x221/0x270 fs/open.c:1330 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd -> #4 (btrfs_trans_num_extwriters){++++}-{0:0}: lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5668 join_transaction+0x19f/0xe60 fs/btrfs/transaction.c:299 start_transaction+0x6fb/0x1180 fs/btrfs/transaction.c:658 btrfs_create_common+0x2c6/0x420 fs/btrfs/inode.c:6633 lookup_open fs/namei.c:3413 [inline] open_last_lookups fs/namei.c:3481 [inline] path_openat+0x12d0/0x2df0 fs/namei.c:3710 do_filp_open+0x264/0x4f0 fs/namei.c:3740 do_sys_openat2+0x124/0x4e0 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+0x221/0x270 fs/open.c:1330 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd -> #3 (btrfs_trans_num_writers){++++}-{0:0}: reacquire_held_locks+0x386/0x650 kernel/locking/lockdep.c:5193 __lock_release kernel/locking/lockdep.c:5382 [inline] lock_release+0x2e2/0x820 kernel/locking/lockdep.c:5688 percpu_up_read include/linux/percpu-rwsem.h:99 [inline] __sb_end_write include/linux/fs.h:1821 [inline] sb_end_intwrite+0x1e/0x1a0 include/linux/fs.h:1877 __btrfs_end_transaction+0x388/0x790 fs/btrfs/transaction.c:995 btrfs_dirty_inode+0x177/0x1c0 fs/btrfs/inode.c:6099 inode_update_time fs/inode.c:1871 [inline] __file_update_time fs/inode.c:2088 [inline] file_update_time+0x3df/0x5d0 fs/inode.c:2119 btrfs_page_mkwrite+0x3a8/0xc80 fs/btrfs/inode.c:8431 do_page_mkwrite+0x19e/0x5e0 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 mm/memory.c:5097 [inline] handle_mm_fault+0x1c63/0x3630 mm/memory.c:5218 do_user_addr_fault+0x69b/0xcb0 arch/x86/mm/fault.c:1428 handle_page_fault arch/x86/mm/fault.c:1519 [inline] exc_page_fault+0x7a/0x110 arch/x86/mm/fault.c:1575 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:570 -> #2 (sb_pagefaults){.+.+}-{0:0}: lock_acquire+0x182/0x3c0 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_pagefault include/linux/fs.h:1930 [inline] btrfs_page_mkwrite+0x1ea/0xc80 fs/btrfs/inode.c:8415 do_page_mkwrite+0x19e/0x5e0 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 mm/memory.c:5097 [inline] handle_mm_fault+0x1c63/0x3630 mm/memory.c:5218 do_user_addr_fault+0x69b/0xcb0 arch/x86/mm/fault.c:1428 handle_page_fault arch/x86/mm/fault.c:1519 [inline] exc_page_fault+0x7a/0x110 arch/x86/mm/fault.c:1575 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:570 -> #1 (&mm->mmap_lock#2){++++}-{3:3}: lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5668 __might_fault+0xb2/0x110 mm/memory.c:5646 _copy_to_user+0x26/0x130 lib/usercopy.c:29 copy_to_user include/linux/uaccess.h:169 [inline] btrfs_ioctl_get_subvol_rootref+0x8cf/0xa90 fs/btrfs/ioctl.c:3203 btrfs_ioctl+0xb7c/0xc10 fs/btrfs/ioctl.c:5556 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl+0xfb/0x170 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd -> #0 (btrfs-root-00){.+.+}-{3:3}: check_prev_add kernel/locking/lockdep.c:3097 [inline] check_prevs_add kernel/locking/lockdep.c:3216 [inline] validate_chain+0x1898/0x6ae0 kernel/locking/lockdep.c:3831 __lock_acquire+0x1292/0x1f60 kernel/locking/lockdep.c:5055 lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5668 down_read_nested+0x3c/0x50 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+0x2b4/0x400 fs/btrfs/locking.c:279 btrfs_search_slot_get_root fs/btrfs/ctree.c:1665 [inline] btrfs_search_slot+0x495/0x2fe0 fs/btrfs/ctree.c:1985 btrfs_update_root+0xf0/0xc60 fs/btrfs/root-tree.c:132 commit_fs_roots+0x4d3/0x710 fs/btrfs/transaction.c:1441 btrfs_commit_transaction+0x147f/0x3760 fs/btrfs/transaction.c:2353 sync_filesystem+0x1bc/0x220 fs/sync.c:66 generic_shutdown_super+0x6b/0x310 fs/super.c:474 kill_anon_super+0x36/0x60 fs/super.c:1086 btrfs_kill_super+0x3d/0x50 fs/btrfs/super.c:2441 deactivate_locked_super+0xa7/0xf0 fs/super.c:332 cleanup_mnt+0x494/0x520 fs/namespace.c:1186 task_work_run+0x243/0x300 kernel/task_work.c:179 exit_task_work include/linux/task_work.h:38 [inline] do_exit+0x664/0x2070 kernel/exit.c:820 do_group_exit+0x1fd/0x2b0 kernel/exit.c:950 __do_sys_exit_group kernel/exit.c:961 [inline] __se_sys_exit_group kernel/exit.c:959 [inline] __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:959 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd other info that might help us debug this: Chain exists of: btrfs-root-00 --> btrfs_trans_num_extwriters --> &fs_info->reloc_mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&fs_info->reloc_mutex); lock(btrfs_trans_num_extwriters); lock(&fs_info->reloc_mutex); lock(btrfs-root-00); *** DEADLOCK *** 5 locks held by syz-executor539/3633: #0: ffff8880733280e0 (&type->s_umount_key#44){+.+.}-{3:3}, at: deactivate_super+0x96/0xd0 fs/super.c:362 #1: ffff88807cebe3f0 (btrfs_trans_completed){.+.+}-{0:0}, at: btrfs_commit_transaction+0x130f/0x3760 fs/btrfs/transaction.c:2295 #2: ffff88807cebe3c8 (btrfs_trans_super_committed){.+.+}-{0:0}, at: btrfs_commit_transaction+0x133e/0x3760 fs/btrfs/transaction.c:2296 #3: ffff88807cebe3a0 (btrfs_trans_unblocked){.+.+}-{0:0}, at: btrfs_commit_transaction+0x136d/0x3760 fs/btrfs/transaction.c:2297 #4: ffff88807cebccc0 (&fs_info->reloc_mutex){+.+.}-{3:3}, at: btrfs_commit_transaction+0x13e8/0x3760 fs/btrfs/transaction.c:2316 stack backtrace: CPU: 1 PID: 3633 Comm: syz-executor539 Not tainted 6.1.0-rc6-syzkaller-00176-g08ad43d554ba #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+0x1b1/0x28e lib/dump_stack.c:106 check_noncircular+0x2cc/0x390 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+0x1898/0x6ae0 kernel/locking/lockdep.c:3831 __lock_acquire+0x1292/0x1f60 kernel/locking/lockdep.c:5055 lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5668 down_read_nested+0x3c/0x50 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+0x2b4/0x400 fs/btrfs/locking.c:279 btrfs_search_slot_get_root fs/btrfs/ctree.c:1665 [inline] btrfs_search_slot+0x495/0x2fe0 fs/btrfs/ctree.c:1985 btrfs_update_root+0xf0/0xc60 fs/btrfs/root-tree.c:132 commit_fs_roots+0x4d3/0x710 fs/btrfs/transaction.c:1441 btrfs_commit_transaction+0x147f/0x3760 fs/btrfs/transaction.c:2353 sync_filesystem+0x1bc/0x220 fs/sync.c:66 generic_shutdown_super+0x6b/0x310 fs/super.c:474 kill_anon_super+0x36/0x60 fs/super.c:1086 btrfs_kill_super+0x3d/0x50 fs/btrfs/super.c:2441 deactivate_locked_super+0xa7/0xf0 fs/super.c:332 cleanup_mnt+0x494/0x520 fs/namespace.c:1186 task_work_run+0x243/0x300 kernel/task_work.c:179 exit_task_work include/linux/task_work.h:38 [inline] do_exit+0x664/0x2070 kernel/exit.c:820 do_group_exit+0x1fd/0x2b0 kernel/exit.c:950 __do_sys_exit_group kernel/exit.c:961 [inline] __se_sys_exit_group kernel/exit.c:959 [inline] __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:959 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7fef8b4ec279 Code: Unable to access opcode bytes at 0x7fef8b4ec24f. RSP: 002b:00007ffebca0a078 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00007fef8b566350 RCX: 00007fef8b4ec279 RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000001 RBP: 0000000000000001 R08: ffffffffffffffc0 R09: 00007fef8b560e40 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fef8b566350 R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000001