Re: [PATCH net-next v3] net: Implement fault injection forcing skb reallocation

[Breno Leitao]

On Thu, Oct 17, 2024 at 03:50:41PM +0200, Paolo Abeni wrote:
> On 10/14/24 15:50, Breno Leitao wrote:
> > Introduce a fault injection mechanism to force skb reallocation. The
> > primary goal is to catch bugs related to pointer invalidation after
> > potential skb reallocation.
> > 
> > The fault injection mechanism aims to identify scenarios where callers
> > retain pointers to various headers in the skb but fail to reload these
> > pointers after calling a function that may reallocate the data. This
> > type of bug can lead to memory corruption or crashes if the old,
> > now-invalid pointers are used.
> > 
> > By forcing reallocation through fault injection, we can stress-test code
> > paths and ensure proper pointer management after potential skb
> > reallocations.
> > 
> > Add a hook for fault injection in the following functions:
> > 
> >   * pskb_trim_rcsum()
> >   * pskb_may_pull_reason()
> >   * pskb_trim()
> > 
> > As the other fault injection mechanism, protect it under a debug Kconfig
> > called CONFIG_FAIL_SKB_FORCE_REALLOC.
> > 
> > This patch was *heavily* inspired by Jakub's proposal from:
> > https://lore.kernel.org/all/20240719174140.47a868e6@xxxxxxxxxx/
> > 
> > CC: Akinobu Mita <akinobu.mita@xxxxxxxxx>
> > Suggested-by: Jakub Kicinski <kuba@xxxxxxxxxx>
> > Signed-off-by: Breno Leitao <leitao@xxxxxxxxxx>
> 
> I'm sorry to nit-pick, but checkpatch laments that the new command line
> argument lacks documentation in
> Documentation/admin-guide/kernel-parameters.txt, and I feel that could be
> actually useful.
> 
> With that, feel free to include my ack in the next revision,

Thanks Paolo, I will send a new updated version soon.