Re: [PATCH net v2] s390/ism: Zerorize dmb at allocation

[Alexandra Winter]

On 28.09.26 17:19, netdev-bot+sinfo@xxxxxxxxxx wrote:
> Hi!
> 
> This is an automated message. This series looks like a fix, but its
> commit messages seem to be missing some information:
> 
>  - Whether the issue was actually triggered, or is only theoretical
>    (e.g. found by code inspection). If it was triggered please include
>    the symptoms, like the stack trace or error messages.
> 
> Please do not repost the series just to address the above. Instead,
> reply to this email with the missing information, so that reviewers
> can take it into account. If the series needs another revision for
> other reasons, please include the information in the commit messages
> then.
> 
> The evaluation is done by an LLM so it may be wrong, if you think
> that is the case please reply and explain.


For reference:

On 28.09.26 17:14, Alexandra Winter wrote:
> Sashiko reported [1] that 'Missing __GFP_ZERO in folio_alloc() causes
> uninitialized kernel memory to be exposed in the receive message buffer'.
> An ism dmb is receive-only, so the data is not leaked to a remote peer. In
> general the smc kernel module (dibs client) will only push newly received
> data to userspace. We still should not have uninitialized data in a receive
> buffer.


As mentioned in the commit message this issue was reported by Sashiko and found
valid by me. I do not see a simple reproducer.

Alexandra