Error while loading dw-i3c-master: UBSAN: shift-out-of-bounds in drivers/i3c/master/dw-i3c-master.c:885:12

[Alexandre Belloni]

Hello Louis,

On 02/12/2025 21:17:31+0100, Louis Sautier wrote:
> Hello,
> 
> I'm running into a bug when loading the dw-i3c-master module on kernel 6.18
> on one specific server. I suspect it has to do with the large number of
> CPUs on the machine (768 threads, from 2 AMD EPYC 9965 processors) but I am
> not sure.
> 
> The system is on Ubuntu 25.10 and a 6.18 kernel with https://gist.githubusercontent.com/sbraz/a6f37fafbcf9354bbe4eace9e9eb48cb/raw/115da594dc9d7ea99b06754847571e6fd76d9da5/config
> (basically Ubuntu's).

Just to be sure, does this also happen with v6.17?

The only change is the shutdown handling so I would guess yes.

-- 
Alexandre Belloni, co-owner and COO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com