syzbot

netlink: 'syz.0.2484': attribute type 2 has an invalid length.
netlink: 12 bytes leftover after parsing attributes in process `syz.0.2484'.
netlink: 28 bytes leftover after parsing attributes in process `syz.0.2484'.
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.0.2484/15845 is trying to acquire lock:
ffff8880597ffad0 (&ovl_i_mutex_dir_key[depth]){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:885 [inline]
ffff8880597ffad0 (&ovl_i_mutex_dir_key[depth]){++++}-{4:4}, at: lookup_slow+0x46/0x70 fs/namei.c:1824

but task is already holding lock:
ffff888055d29088 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1de/0x540 fs/kernfs/file.c:343

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (&of->mutex){+.+.}-{4:4}:
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
       __mutex_lock_common kernel/locking/mutex.c:598 [inline]
       __mutex_lock+0x187/0x1350 kernel/locking/mutex.c:760
       kernfs_fop_write_iter+0x1de/0x540 fs/kernfs/file.c:343
       iter_file_splice_write+0x975/0x10e0 fs/splice.c:738
       do_splice_from fs/splice.c:938 [inline]
       do_splice+0xc79/0x1660 fs/splice.c:1351
       __do_splice fs/splice.c:1433 [inline]
       __do_sys_splice fs/splice.c:1636 [inline]
       __se_sys_splice+0x2e1/0x460 fs/splice.c:1618
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #2 (&pipe->mutex){+.+.}-{4:4}:
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
       __mutex_lock_common kernel/locking/mutex.c:598 [inline]
       __mutex_lock+0x187/0x1350 kernel/locking/mutex.c:760
       iter_file_splice_write+0x1e0/0x10e0 fs/splice.c:683
       do_splice_from fs/splice.c:938 [inline]
       do_splice+0xc79/0x1660 fs/splice.c:1351
       __do_splice fs/splice.c:1433 [inline]
       __do_sys_splice fs/splice.c:1636 [inline]
       __se_sys_splice+0x2e1/0x460 fs/splice.c:1618
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (sb_writers#5){.+.+}-{0:0}:
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
       percpu_down_read_internal include/linux/percpu-rwsem.h:53 [inline]
       percpu_down_read_freezable include/linux/percpu-rwsem.h:83 [inline]
       __sb_start_write include/linux/fs.h:1799 [inline]
       sb_start_write+0x4d/0x1c0 include/linux/fs.h:1935
       mnt_want_write+0x41/0x90 fs/namespace.c:557
       ovl_create_object+0xfc/0x310 fs/overlayfs/dir.c:651
       lookup_open fs/namei.c:3708 [inline]
       open_last_lookups fs/namei.c:3807 [inline]
       path_openat+0x14f4/0x3830 fs/namei.c:4043
       do_filp_open+0x1fa/0x410 fs/namei.c:4073
       do_sys_openat2+0x121/0x1c0 fs/open.c:1435
       do_sys_open fs/open.c:1450 [inline]
       __do_sys_openat fs/open.c:1466 [inline]
       __se_sys_openat fs/open.c:1461 [inline]
       __x64_sys_openat+0x138/0x170 fs/open.c:1461
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&ovl_i_mutex_dir_key[depth]){++++}-{4:4}:
       check_prev_add kernel/locking/lockdep.c:3165 [inline]
       check_prevs_add kernel/locking/lockdep.c:3284 [inline]
       validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3908
       __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
       down_read+0x46/0x2e0 kernel/locking/rwsem.c:1537
       inode_lock_shared include/linux/fs.h:885 [inline]
       lookup_slow+0x46/0x70 fs/namei.c:1824
       walk_component+0x2d2/0x400 fs/namei.c:2129
       lookup_last fs/namei.c:2630 [inline]
       path_lookupat+0x163/0x430 fs/namei.c:2654
       filename_lookup+0x212/0x570 fs/namei.c:2683
       kern_path+0x35/0x50 fs/namei.c:2816
       lookup_bdev+0xc0/0x280 block/bdev.c:1205
       resume_store+0x169/0x460 kernel/power/hibernate.c:1296
       kernfs_fop_write_iter+0x3af/0x540 fs/kernfs/file.c:352
       new_sync_write fs/read_write.c:593 [inline]
       vfs_write+0x5c9/0xb30 fs/read_write.c:686
       ksys_write+0x145/0x250 fs/read_write.c:738
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

Chain exists of:
  &ovl_i_mutex_dir_key[depth] --> &pipe->mutex --> &of->mutex

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&of->mutex);
                               lock(&pipe->mutex);
                               lock(&of->mutex);
  rlock(&ovl_i_mutex_dir_key[depth]);

 *** DEADLOCK ***

4 locks held by syz.0.2484/15845:
 #0: ffff8880286a2d38 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x247/0x320 fs/file.c:1232
 #1: ffff88802fcb4428 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:3108 [inline]
 #1: ffff88802fcb4428 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x211/0xb30 fs/read_write.c:682
 #2: ffff888055d29088 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1de/0x540 fs/kernfs/file.c:343
 #3: ffff888140ef22d8 (kn->active#62){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
 #3: ffff888140ef22d8 (kn->active#62){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x231/0x540 fs/kernfs/file.c:344

stack backtrace:
CPU: 0 UID: 0 PID: 15845 Comm: syz.0.2484 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_circular_bug+0x2ee/0x310 kernel/locking/lockdep.c:2043
 check_noncircular+0x134/0x160 kernel/locking/lockdep.c:2175
 check_prev_add kernel/locking/lockdep.c:3165 [inline]
 check_prevs_add kernel/locking/lockdep.c:3284 [inline]
 validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3908
 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237
 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
 down_read+0x46/0x2e0 kernel/locking/rwsem.c:1537
 inode_lock_shared include/linux/fs.h:885 [inline]
 lookup_slow+0x46/0x70 fs/namei.c:1824
 walk_component+0x2d2/0x400 fs/namei.c:2129
 lookup_last fs/namei.c:2630 [inline]
 path_lookupat+0x163/0x430 fs/namei.c:2654
 filename_lookup+0x212/0x570 fs/namei.c:2683
 kern_path+0x35/0x50 fs/namei.c:2816
 lookup_bdev+0xc0/0x280 block/bdev.c:1205
 resume_store+0x169/0x460 kernel/power/hibernate.c:1296
 kernfs_fop_write_iter+0x3af/0x540 fs/kernfs/file.c:352
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0x5c9/0xb30 fs/read_write.c:686
 ksys_write+0x145/0x250 fs/read_write.c:738
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1f1998eba9
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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f1f1a832038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f1f19bd5fa0 RCX: 00007f1f1998eba9
RDX: 0000000000000012 RSI: 0000200000000000 RDI: 0000000000000008
RBP: 00007f1f19a11e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1f19bd6038 R14: 00007f1f19bd5fa0 R15: 00007ffe5ad6c118
 </TASK>
md: async del_gendisk mode will be removed in future, please upgrade to mdadm-4.5+
PM: Image not found (code -6)