Re: [PATCH v2 1/5] nfsd: prevent callback tasks running concurrently

[ChenXiaoSong]

Hi Jeff:

Do you have any suggestions for this null-ptr-deref issue?

Here is the link to the vmcore analysis:

https://chenxiaosong.com/en/nfs/en-null-ptr-deref-in-nfsd4_probe_callback.html

Thanks,
ChenXiaoSong.

在 2025/6/11 15:12, ChenXiaoSong 写道:
> 在 2025/6/10 19:09, Jeff Layton 写道:
> > Synchronization was probably too strong a word. I remember looking over
> > this code and convincing myself that the probe callback wasn't subject
> > to the same races as the others, but I think that was mostly because
> > the outcome of those races was not harmful. Note that the probe itself
> > can actually be run at the start of a completely unrelated callback to
> > the same client.
> >
> > So you hit a NULL pointer in __queue_work()? The work_struct is
> > embedded in the nfs4_client so that would probably imply that that the
> > nfs4_client struct was corrupt?
> >
> > You may want to get a vmcore and analyze it if you can reproduce this.
>
> Thanks for your reply.
>
> I have already got a vmcore. Here is the link to the vmcore analysis:
>
> https://chenxiaosong.com/en/nfs/en-null-ptr-deref-in- 
> nfsd4_probe_callback.html
>
> Please let me know if you need any more detailed information.
>
> Thanks,
> ChenXiaoSong.