Re: [PATCH] NFSD: Avoid corruption of a referring call list

[Jeff Layton <jlayton@kernel.org>]

On Sun, 2025-06-08 at 18:08 -0400, Chuck Lever wrote:
> From: Chuck Lever <chuck.lever@oracle.com>
> 
> The new code neglects to remove a freshly-allocated RCL from the
> callback's referring call list when no matching referring call is
> found.
> 
> Reported-by: kernel test robot <lkp@intel.com>
> Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
> Closes: https://lore.kernel.org/r/202505171002.cE46sdj5-lkp@intel.com/
> Fixes: 4f3c8d8c9e10 ("NFSD: Implement CB_SEQUENCE referring call lists")
> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
> ---
>  fs/nfsd/nfs4callback.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> I don't recall seeing this on the mailing list. Targeting this
> one for nfsd-fixes.
> 
> 
> diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
> index ccb00aa93be0..e00b2aea8da2 100644
> --- a/fs/nfsd/nfs4callback.c
> +++ b/fs/nfsd/nfs4callback.c
> @@ -1409,6 +1409,7 @@ void nfsd41_cb_referring_call(struct nfsd4_callback *cb,
>  out:
>  	if (!rcl->__nr_referring_calls) {
>  		cb->cb_nr_referring_call_list--;
> +		list_del(&rcl->__list);
>  		kfree(rcl);
>  	}
>  }

Nice catch.

Reviewed-by: Jeff Layton <jlayton@kernel.org>