Re: [PATCH] scsi: target: Fix recursive locking in __configfs_open_file()

Bart Van Assche
2026-01-21T17:59:57Z

On 1/21/26 9:51 AM, Prithvi wrote:
> I tried using lockdep_register_key() and lockdep_unregister_key() for the
> frag_sem lock, however it stil gives the possible recursive locking
> warning. Here is the patch and the bug report from its test:
>
> https://lore.kernel.org/all/6767d8ea.050a0220.226966.0021.GAE@google.com/T/#m3203ceddf3423b7116ba9225d182771608f93a6f
>
> Would using down_read_nested() and subclasses be a better option here?
>
> I also checked out some documentation regarding it and learnt that to use
> the _nested() form, the hierarchy among the locks should be mapped
> accurately; however, IIUC, there isn't any hierarchy between the locks in
> this case, is this right?
>
> Apologies if I am missing something obvious here, and thanks for your
> time and guidance.

This is unexpected. Please ask help from someone who is familiar with
VFS internals. I'm not familiar with these internals.

Thanks,

Bart.