====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G L Y ------------------------------------------------------ syz.3.7047/23109 is trying to acquire lock: ffff88805c093960 (&type->i_mutex_dir_key#5){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1039 [inline] ffff88805c093960 (&type->i_mutex_dir_key#5){++++}-{4:4}, at: lookup_slow+0x46/0x80 fs/namei.c:1935 but task is already holding lock: ffff888034e072e0 (DCACHE_PAR_LOOKUP){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] ffff888034e072e0 (DCACHE_PAR_LOOKUP){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] ffff888034e072e0 (DCACHE_PAR_LOOKUP){+.+.}-{0:0}, at: __d_alloc_parallel+0x39e/0x1700 fs/dcache.c:2881 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (DCACHE_PAR_LOOKUP){+.+.}-{0:0}: 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 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 -> #0 (&type->i_mutex_dir_key#5){++++}-{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_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_open+0x94b/0x1970 fs/namei.c:4530 open_last_lookups fs/namei.c:4769 [inline] path_openat+0x673/0x1da0 fs/namei.c:5008 do_file_open+0x23e/0x4a0 fs/namei.c:5040 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 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(DCACHE_PAR_LOOKUP); lock(&type->i_mutex_dir_key#5); lock(DCACHE_PAR_LOOKUP); rlock(&type->i_mutex_dir_key#5); *** DEADLOCK *** locks held by syz.3.7047/23109: 3, last CPU#0: #0: ffff888071746460 (sb_writers#26){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:505 #1: ffff88804cb29740 (&ovl_i_mutex_dir_key[depth]){++++}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline] #1: ffff88804cb29740 (&ovl_i_mutex_dir_key[depth]){++++}-{4:4}, at: lookup_open+0x246/0x1970 fs/namei.c:4462 #2: ffff888034e072e0 (DCACHE_PAR_LOOKUP){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] #2: ffff888034e072e0 (DCACHE_PAR_LOOKUP){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #2: ffff888034e072e0 (DCACHE_PAR_LOOKUP){+.+.}-{0:0}, at: __d_alloc_parallel+0x39e/0x1700 fs/dcache.c:2881 stack backtrace: CPU: 0 UID: 0 PID: 23109 Comm: syz.3.7047 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: 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_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_open+0x94b/0x1970 fs/namei.c:4530 open_last_lookups fs/namei.c:4769 [inline] path_openat+0x673/0x1da0 fs/namei.c:5008 do_file_open+0x23e/0x4a0 fs/namei.c:5040 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 RIP: 0033:0x7fa3ab99e159 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fa3ac8c9028 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fa3abc25fa0 RCX: 00007fa3ab99e159 RDX: 0000000000000040 RSI: 0000200000000400 RDI: ffffffffffffff9c RBP: 00007fa3aba3506b R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000083 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fa3abc26038 R14: 00007fa3abc25fa0 R15: 00007ffcafc7dc08