On 10/7/24 17:20, Breno Leitao wrote:
On Sat, Oct 05, 2024 at 01:38:59PM +0900, Akinobu Mita wrote:
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.
I think it might make more sense to be network interface specific. For
instance, only fault inject in interface `ethx`.
Wasn't there some error injection infra that allows to optionally
run bpf? That would cover the filtering problem. ALLOW_ERROR_INJECTION,
maybe?
--
Pavel Begunkov
