On Thursday, November 13th, 2025 at 11:12 AM, Chuck Lever <[email protected]> wrote:
> Then I would start looking for differences between the Debian 13 and > Fedora 43 kernel code base under net/sunrpc/ . > > Alternatively, "git bisect first, ask questions later" ... :-) This is outside my day-to-day, so I don't have a workflow for this kind of testing/debugging, but I'll see what I can do. Thanks for the starting place. > So I didn't find an indication of whether this was sec=krb5, sec=krb5i, > or sec=krb5p. That might narrow down where the code changed. I confirmed the issue with all 3 krb5 sec modes, in both the 6.12 kernel that ships with Debian 13 and the 6.17 that currently ships with Debian Sid/unstable. Similarly, I confirmed NFSv4.2, 4.1 and 4.0 are impacted. > Also, the xdr_buf might have a page boundary positioned in the middle of > an XDR data item. Knowing which data item is being decoded where the > "overflow" occurs might be helpful (I think adding pr_info() call sites > or trace_printk() will be adequate to gain some better observability). No experience with kernel hacking, so I'm not confident I can locate meaningful places to insert those. I'll see where some snooping and a bisect gets me. Failing that, if anyone has recommendations on where to add those calls, I'd appreciate the guidance. TWR
