XPost: linux.debian.bugs.dist, linux.kernel   
   From: TWR@tylerwross.com   
      
   On Thursday, November 13th, 2025 at 11:12 AM, Chuck Lever  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   
      
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