Re: ls input/output error ("NFS: readdir(/) returns -5") on krb5 NFSv4 client using SHA2

Chuck Lever
2025-11-14T14:19:32Z

On 11/14/25 12:09 AM, Tyler W. Ross wrote:
> On Thursday, November 13th, 2025 at 9:35 PM, Tyler W. Ross <TWR@tylerwross.com> wrote:
>
>> I tried a couple vanilla/stock kernels today, without success.
>>
>> Most notably, I built 6.17.8 from upstream using the Kconfig from the
>> working Fedora 43 client in my lab ("config-6.17.5-300.fc43.x86_64").
>>
>> Unfortunately, the rpc_xdr_overflow still occurs with this kernel.
>
> Quick addendum:
>
> I had not tried Debian 12, because CONFIG_RPCSEC_GSS_KRB5_ENCTYPES_AES_SHA2
> was not enabled in the shipped Kconfig.
>
> I just spun up a Debian 12 VM and installed the aforementioned
> upstream 6.17.8 with Fedora 43 Kconfig kernel and confirmed the issue
> also occurs on Debian 12.
Then I would say further hunting for the broken commit is going to be
fruitless. Adding the WARNs in net/sunrpc/xdr.c is a good next step so
we see which XDR data item (assuming it's the same one every time) is
failing to decode.

--
Chuck Lever