====================================================== WARNING: possible circular locking dependency detected 6.1.0-rc5-syzkaller-00008-ge01d50cbd6ee #0 Not tainted ------------------------------------------------------ syz-executor589/3733 is trying to acquire lock: ffff88807658c650 (sb_internal#2){.+.+}-{0:0}, at: btrfs_dirty_inode+0xcc/0x1c0 fs/btrfs/inode.c:6085 but task is already holding lock: ffff88807d23acd8 (&mm->mmap_lock#2){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline] ffff88807d23acd8 (&mm->mmap_lock#2){++++}-{3:3}, at: vm_mmap_pgoff+0x14d/0x2b0 mm/util.c:518 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #5 (&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 -> #4 (btrfs-root-00){++++}-{3:3}: 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 ptrace_notify+0x29a/0x340 kernel/signal.c:2354 ptrace_report_syscall include/linux/ptrace.h:420 [inline] ptrace_report_syscall_exit include/linux/ptrace.h:482 [inline] syscall_exit_work+0x8c/0xe0 kernel/entry/common.c:251 syscall_exit_to_user_mode_prepare+0x63/0xc0 kernel/entry/common.c:278 __syscall_exit_to_user_mode_work kernel/entry/common.c:283 [inline] syscall_exit_to_user_mode+0xa/0x60 kernel/entry/common.c:296 do_syscall_64+0x49/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x63/0xcd -> #3 (&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 -> #2 (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 -> #1 (btrfs_trans_num_writers){++++}-{0:0}: lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5668 join_transaction+0x17a/0xe60 fs/btrfs/transaction.c:298 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 -> #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+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 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+0x5cb/0x1180 fs/btrfs/transaction.c:652 btrfs_dirty_inode+0xcc/0x1c0 fs/btrfs/inode.c:6085 inode_update_time fs/inode.c:1871 [inline] touch_atime+0x315/0x630 fs/inode.c:1944 file_accessed include/linux/fs.h:2521 [inline] btrfs_file_mmap+0xbb/0x120 fs/btrfs/file.c:2333 call_mmap include/linux/fs.h:2196 [inline] mmap_region+0xfe6/0x1e20 mm/mmap.c:2625 do_mmap+0x8d9/0xf30 mm/mmap.c:1412 vm_mmap_pgoff+0x19e/0x2b0 mm/util.c:520 ksys_mmap_pgoff+0x48c/0x6d0 mm/mmap.c:1458 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: sb_internal#2 --> btrfs-root-00 --> &mm->mmap_lock#2 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&mm->mmap_lock#2); lock(btrfs-root-00); lock(&mm->mmap_lock#2); lock(sb_internal#2); *** DEADLOCK *** 2 locks held by syz-executor589/3733: #0: ffff88807d23acd8 (&mm->mmap_lock#2){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline] #0: ffff88807d23acd8 (&mm->mmap_lock#2){++++}-{3:3}, at: vm_mmap_pgoff+0x14d/0x2b0 mm/util.c:518 #1: ffff88807658c460 (sb_writers#9){.+.+}-{0:0}, at: file_accessed include/linux/fs.h:2521 [inline] #1: ffff88807658c460 (sb_writers#9){.+.+}-{0:0}, at: btrfs_file_mmap+0xbb/0x120 fs/btrfs/file.c:2333 stack backtrace: CPU: 0 PID: 3733 Comm: syz-executor589 Not tainted 6.1.0-rc5-syzkaller-00008-ge01d50cbd6ee #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 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+0x5cb/0x1180 fs/btrfs/transaction.c:652 btrfs_dirty_inode+0xcc/0x1c0 fs/btrfs/inode.c:6085 inode_update_time fs/inode.c:1871 [inline] touch_atime+0x315/0x630 fs/inode.c:1944 file_accessed include/linux/fs.h:2521 [inline] btrfs_file_mmap+0xbb/0x120 fs/btrfs/file.c:2333 call_mmap include/linux/fs.h:2196 [inline] mmap_region+0xfe6/0x1e20 mm/mmap.c:2625 do_mmap+0x8d9/0xf30 mm/mmap.c:1412 vm_mmap_pgoff+0x19e/0x2b0 mm/util.c:520 ksys_mmap_pgoff+0x48c/0x6d0 mm/mmap.c:1458 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: 0033:0x7f714153d709 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffda0941a38 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007f7141585938 RCX: 00007f714153d709 RDX: 0000000000000001 RSI: 0000000000400000 RDI: 0000000020000000 RBP: 00007f7141585850 R08: 0000000000000006 R09: 0000000000000000 R10: 0000000000010012 R11: 0000000000000246 R12: 00007f7141585708 R13: 00007f71415856a0 R14: 00007ffda0941a80 R15: 0000000000000006