====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz-executor324/6058 is trying to acquire lock: ffff888024d4e3e8 (&sb->s_type->i_mutex_key#10){++++}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline] ffff888024d4e3e8 (&sb->s_type->i_mutex_key#10){++++}-{4:4}, at: set_blocksize+0x1e6/0x440 block/bdev.c:202 but task is already holding lock: ffff888027eb26a8 (btrfs_trans_num_extwriters){.+.+}-{0:0}, at: join_transaction+0x6b2/0xd40 fs/btrfs/transaction.c:331 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (btrfs_trans_num_extwriters){.+.+}-{0:0}: join_transaction+0x18a/0xd40 fs/btrfs/transaction.c:356 start_transaction+0x731/0x1830 fs/btrfs/transaction.c:770 btrfs_create_common+0x15c/0x310 fs/btrfs/inode.c:6991 lookup_open+0xedc/0x1970 fs/namei.c:4569 open_last_lookups fs/namei.c:4768 [inline] path_openat+0x70c/0x20f0 fs/namei.c:5007 do_file_open+0x23e/0x4a0 fs/namei.c:5039 do_sys_openat2+0x115/0x200 fs/open.c:1442 do_sys_open fs/open.c:1448 [inline] __do_sys_openat fs/open.c:1464 [inline] __se_sys_openat fs/open.c:1459 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1459 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #2 (btrfs_trans_num_writers){.+.+}-{0:0}: __lock_release kernel/locking/lockdep.c:5627 [inline] lock_release+0x1a3/0x3c0 kernel/locking/lockdep.c:5964 percpu_up_read include/linux/percpu-rwsem.h:114 [inline] __sb_end_write include/linux/fs/super.h:14 [inline] sb_end_intwrite+0x26/0x190 include/linux/fs/super.h:101 __btrfs_end_transaction+0x237/0x640 fs/btrfs/transaction.c:1147 btrfs_dirty_inode+0x14c/0x190 fs/btrfs/inode.c:6444 touch_atime+0x2f8/0x670 fs/inode.c:2325 file_accessed include/linux/fs.h:2279 [inline] btrfs_file_mmap_prepare+0x172/0x1f0 fs/btrfs/file.c:2003 vfs_mmap_prepare include/linux/fs.h:2071 [inline] call_mmap_prepare mm/vma.c:2815 [inline] __mmap_region mm/vma.c:2913 [inline] mmap_region+0xe88/0x23c0 mm/vma.c:3014 do_mmap+0xe0a/0x1300 mm/mmap.c:573 vm_mmap_pgoff+0x272/0x4e0 mm/util.c:581 ksys_mmap_pgoff+0x4dc/0x760 mm/mmap.c:619 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #1 (&mm->mmap_lock){++++}-{4:4}: __might_fault+0xcb/0x130 mm/memory.c:7419 _copy_to_iter+0xf9/0x1810 lib/iov_iter.c:196 copy_page_to_iter+0x23f/0x330 lib/iov_iter.c:374 copy_folio_to_iter include/linux/uio.h:204 [inline] filemap_read+0x7af/0x11e0 mm/filemap.c:2893 blkdev_read_iter+0x2f1/0x420 block/fops.c:838 new_sync_read fs/read_write.c:493 [inline] vfs_read+0x595/0xa80 fs/read_write.c:574 ksys_read+0x150/0x270 fs/read_write.c:716 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (&sb->s_type->i_mutex_key#10){++++}-{4:4}: check_prev_add kernel/locking/lockdep.c:3209 [inline] check_prevs_add kernel/locking/lockdep.c:3328 [inline] validate_chain kernel/locking/lockdep.c:3952 [inline] __lock_acquire+0x164c/0x2de0 kernel/locking/lockdep.c:5288 lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5942 down_write+0x91/0x200 kernel/locking/rwsem.c:1631 inode_lock include/linux/fs.h:1024 [inline] set_blocksize+0x1e6/0x440 block/bdev.c:202 btrfs_init_new_device+0xa4e/0x1cf0 fs/btrfs/volumes.c:3046 btrfs_ioctl_add_dev+0x1ad/0x640 fs/btrfs/ioctl.c:2571 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Chain exists of: &sb->s_type->i_mutex_key#10 --> btrfs_trans_num_writers --> btrfs_trans_num_extwriters Possible unsafe locking scenario: CPU0 CPU1 ---- ---- rlock(btrfs_trans_num_extwriters); lock(btrfs_trans_num_writers); lock(btrfs_trans_num_extwriters); lock(&sb->s_type->i_mutex_key#10); *** DEADLOCK *** locks held by syz-executor324/6058: 3, last CPU#0: #0: ffff8880139a2650 (sb_internal#2){.+.+}-{0:0}, at: btrfs_init_new_device+0x7f3/0x1cf0 fs/btrfs/volumes.c:3022 #1: ffff888027eb2680 (btrfs_trans_num_writers){.+.+}-{0:0}, at: join_transaction+0x6b2/0xd40 fs/btrfs/transaction.c:331 #2: ffff888027eb26a8 (btrfs_trans_num_extwriters){.+.+}-{0:0}, at: join_transaction+0x6b2/0xd40 fs/btrfs/transaction.c:331 stack backtrace: CPU: 0 UID: 0 PID: 6058 Comm: syz-executor324 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/15/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_circular_bug+0x2e2/0x300 kernel/locking/lockdep.c:2087 check_noncircular+0x12f/0x150 kernel/locking/lockdep.c:2219 check_prev_add kernel/locking/lockdep.c:3209 [inline] check_prevs_add kernel/locking/lockdep.c:3328 [inline] validate_chain kernel/locking/lockdep.c:3952 [inline] __lock_acquire+0x164c/0x2de0 kernel/locking/lockdep.c:5288 lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5942 down_write+0x91/0x200 kernel/locking/rwsem.c:1631 inode_lock include/linux/fs.h:1024 [inline] set_blocksize+0x1e6/0x440 block/bdev.c:202 btrfs_init_new_device+0xa4e/0x1cf0 fs/btrfs/volumes.c:3046 btrfs_ioctl_add_dev+0x1ad/0x640 fs/btrfs/ioctl.c:2571 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f8612ea2ebb Code: 00 48 89 44 24 18 31 c0 48 8d 44 24 60 c7 04 24 10 00 00 00 48 89 44 24 08 48 8d 44 24 20 48 89 44 24 10 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 1c 48 8b 44 24 18 64 48 2b 04 25 28 00 00 RSP: 002b:00007ffe693cf9a0 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f8612ea2ebb RDX: 00007ffe693d2bf0 RSI: 000000005000940a RDI: 0000000000000003 RBP: 00007ffe693d2bf0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe693cfb20 R13: 0000000000000000 R14: 00007f8612e71000 R15: 00007ffe693cff70