======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Tainted: G             L     Y
------------------------------------------------------
iou-wrk-20458/20462 is trying to acquire lock:
ffff88807bed45e0 (DCACHE_PAR_LOOKUP){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
ffff88807bed45e0 (DCACHE_PAR_LOOKUP){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
ffff88807bed45e0 (DCACHE_PAR_LOOKUP){+.+.}-{0:0}, at: __d_alloc_parallel+0x39e/0x1700 fs/dcache.c:2881

but task is already holding lock:
ffff88807faa5df0 (&type->i_mutex_dir_key#5){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1039 [inline]
ffff88807faa5df0 (&type->i_mutex_dir_key#5){++++}-{4:4}, at: lookup_slow+0x46/0x80 fs/namei.c:1935

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&type->i_mutex_dir_key#5){++++}-{4:4}:
       down_read+0x45/0x320 kernel/locking/rwsem.c:1574
       inode_lock_shared include/linux/fs.h:1039 [inline]
       lookup_slow+0x46/0x80 fs/namei.c:1935
       ovl_lookup_positive_unlocked fs/overlayfs/namei.c:216 [inline]
       ovl_lookup_single+0x323/0xe90 fs/overlayfs/namei.c:260
       ovl_lookup_layer+0x377/0x440 fs/overlayfs/namei.c:365
       ovl_lookup_layers fs/overlayfs/namei.c:1109 [inline]
       ovl_lookup+0x5e5/0x1c80 fs/overlayfs/namei.c:1403
       __lookup_slow+0x1fb/0x2f0 fs/namei.c:1919
       lookup_slow+0x59/0x80 fs/namei.c:1936
       walk_component fs/namei.c:2282 [inline]
       lookup_last fs/namei.c:2789 [inline]
       path_lookupat+0x3f5/0x8c0 fs/namei.c:2813
       filename_lookup+0x265/0x5d0 fs/namei.c:2842
       filename_listxattr fs/xattr.c:971 [inline]
       path_listxattrat+0x13b/0x3f0 fs/xattr.c:1001
       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 (DCACHE_PAR_LOOKUP){+.+.}-{0:0}:
       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
       d_wait_lookup fs/dcache.c:2838 [inline]
       __d_alloc_parallel+0xc32/0x1700 fs/dcache.c:2942
       __lookup_slow+0x82/0x2f0 fs/namei.c:1904
       lookup_slow+0x59/0x80 fs/namei.c:1936
       walk_component fs/namei.c:2282 [inline]
       link_path_walk+0xd22/0x1910 fs/namei.c:2656
       path_openat+0x1c4/0x1da0 fs/namei.c:5007
       do_file_open+0x23e/0x4a0 fs/namei.c:5040
       io_openat2+0x3ca/0x650 io_uring/openclose.c:150
       __io_issue_sqe+0x180/0x450 io_uring/io_uring.c:1427
       io_issue_sqe+0x164/0x1120 io_uring/io_uring.c:1450
       io_wq_submit_work+0x867/0xda0 io_uring/io_uring.c:1573
       io_worker_handle_work+0x77a/0x1160 io_uring/io-wq.c:663
       io_wq_worker+0x485/0xfd0 io_uring/io-wq.c:718
       ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  rlock(&type->i_mutex_dir_key#5);
                               lock(DCACHE_PAR_LOOKUP);
                               lock(&type->i_mutex_dir_key#5);
  lock(DCACHE_PAR_LOOKUP);

 *** DEADLOCK ***

locks held by iou-wrk-20458/20462: 1, last CPU#1:
 #0: ffff88807faa5df0 (&type->i_mutex_dir_key#5){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1039 [inline]
 #0: ffff88807faa5df0 (&type->i_mutex_dir_key#5){++++}-{4:4}, at: lookup_slow+0x46/0x80 fs/namei.c:1935

stack backtrace:
CPU: 1 UID: 0 PID: 20462 Comm: iou-wrk-20458 Tainted: G             L     Y syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP, [Y]=FORCED_BIND
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <TASK>
 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
 d_wait_lookup fs/dcache.c:2838 [inline]
 __d_alloc_parallel+0xc32/0x1700 fs/dcache.c:2942
 __lookup_slow+0x82/0x2f0 fs/namei.c:1904
 lookup_slow+0x59/0x80 fs/namei.c:1936
 walk_component fs/namei.c:2282 [inline]
 link_path_walk+0xd22/0x1910 fs/namei.c:2656
 path_openat+0x1c4/0x1da0 fs/namei.c:5007
 do_file_open+0x23e/0x4a0 fs/namei.c:5040
 io_openat2+0x3ca/0x650 io_uring/openclose.c:150
 __io_issue_sqe+0x180/0x450 io_uring/io_uring.c:1427
 io_issue_sqe+0x164/0x1120 io_uring/io_uring.c:1450
 io_wq_submit_work+0x867/0xda0 io_uring/io_uring.c:1573
 io_worker_handle_work+0x77a/0x1160 io_uring/io-wq.c:663
 io_wq_worker+0x485/0xfd0 io_uring/io-wq.c:718
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>