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

[Akinobu Mita]

2024年10月2日(水) 20:37 Breno Leitao <leitao@xxxxxxxxxx>:
>
> 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>

This new addition seems sensible.  It might be more useful to have a filter
that allows you to specify things like protocol family.