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

[Paolo Abeni <pabeni@redhat.com>]

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@kernel.org/
> 
> CC: Akinobu Mita <akinobu.mita@gmail.com>
> Suggested-by: Jakub Kicinski <kuba@kernel.org>
> Signed-off-by: Breno Leitao <leitao@debian.org>

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