====================================================== WARNING: possible circular locking dependency detected 6.1.141-syzkaller #0 Not tainted ------------------------------------------------------ syz.3.181/5244 is trying to acquire lock: ffff0000d16f6460 (sb_writers#13){.+.+}-{0:0}, at: mnt_want_write_file+0x64/0x1e8 fs/namespace.c:437 but task is already holding lock: ffff0000d5f67090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x7c/0xe8 fs/reiserfs/lock.c:27 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&sbi->lock){+.+.}-{3:3}: __mutex_lock_common+0x190/0x1f38 kernel/locking/mutex.c:603 __mutex_lock kernel/locking/mutex.c:747 [inline] mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799 reiserfs_write_lock+0x7c/0xe8 fs/reiserfs/lock.c:27 reiserfs_dirty_inode+0xe0/0x200 fs/reiserfs/super.c:704 __mark_inode_dirty+0x2e8/0x12a0 fs/fs-writeback.c:2433 generic_update_time fs/inode.c:1946 [inline] inode_update_time fs/inode.c:1959 [inline] touch_atime+0x40c/0x7d0 fs/inode.c:2031 file_accessed include/linux/fs.h:2600 [inline] filemap_read+0x1dd4/0x1fd8 mm/filemap.c:2836 generic_file_read_iter+0xf8/0x5a8 mm/filemap.c:2914 do_iter_readv_writev fs/read_write.c:-1 [inline] do_iter_read+0x4fc/0x8c4 fs/read_write.c:796 vfs_iter_read+0x88/0xac fs/read_write.c:838 lo_read_simple drivers/block/loop.c:285 [inline] do_req_filebacked drivers/block/loop.c:495 [inline] loop_handle_cmd drivers/block/loop.c:1907 [inline] loop_process_work+0x908/0x1f8c drivers/block/loop.c:1942 loop_workfn+0x50/0x64 drivers/block/loop.c:1966 process_one_work+0x7f4/0x13a8 kernel/workqueue.c:2292 worker_thread+0x8c8/0xfbc kernel/workqueue.c:2439 kthread+0x250/0x2d8 kernel/kthread.c:376 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:864 -> #0 (sb_writers#13){.+.+}-{0:0}: check_prev_add kernel/locking/lockdep.c:3090 [inline] check_prevs_add kernel/locking/lockdep.c:3209 [inline] validate_chain kernel/locking/lockdep.c:3825 [inline] __lock_acquire+0x293c/0x6544 kernel/locking/lockdep.c:5049 lock_acquire+0x20c/0x644 kernel/locking/lockdep.c:5662 percpu_down_read include/linux/percpu-rwsem.h:51 [inline] __sb_start_write include/linux/fs.h:1891 [inline] sb_start_write+0x74/0x2ac include/linux/fs.h:1966 mnt_want_write_file+0x64/0x1e8 fs/namespace.c:437 reiserfs_ioctl+0x114/0x450 fs/reiserfs/ioctl.c:103 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+0x14c/0x1c8 fs/ioctl.c:856 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x138 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&sbi->lock); lock(sb_writers#13); lock(&sbi->lock); lock(sb_writers#13); *** DEADLOCK *** 1 lock held by syz.3.181/5244: #0: ffff0000d5f67090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x7c/0xe8 fs/reiserfs/lock.c:27 stack backtrace: CPU: 0 PID: 5244 Comm: syz.3.181 Not tainted 6.1.141-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Call trace: dump_backtrace+0x1c8/0x1f4 arch/arm64/kernel/stacktrace.c:158 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165 __dump_stack+0x30/0x40 lib/dump_stack.c:88 dump_stack_lvl+0xf8/0x160 lib/dump_stack.c:106 dump_stack+0x1c/0x5c lib/dump_stack.c:113 print_circular_bug+0x148/0x1b0 kernel/locking/lockdep.c:2048 check_noncircular+0x240/0x2d4 kernel/locking/lockdep.c:2170 check_prev_add kernel/locking/lockdep.c:3090 [inline] check_prevs_add kernel/locking/lockdep.c:3209 [inline] validate_chain kernel/locking/lockdep.c:3825 [inline] __lock_acquire+0x293c/0x6544 kernel/locking/lockdep.c:5049 lock_acquire+0x20c/0x644 kernel/locking/lockdep.c:5662 percpu_down_read include/linux/percpu-rwsem.h:51 [inline] __sb_start_write include/linux/fs.h:1891 [inline] sb_start_write+0x74/0x2ac include/linux/fs.h:1966 mnt_want_write_file+0x64/0x1e8 fs/namespace.c:437 reiserfs_ioctl+0x114/0x450 fs/reiserfs/ioctl.c:103 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+0x14c/0x1c8 fs/ioctl.c:856 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x138 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585