Re: [PATCH v2] mm: fix unexpected changes to {failslab|fail_page_alloc}.attr

[Akinobu Mita]

2022年11月8日(火) 12:52 Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx>:
>
> When we specify __GFP_NOWARN, we only expect that no warnings
> will be issued for current caller. But in the __should_failslab()
> and __should_fail_alloc_page(), the local GFP flags alter the
> global {failslab|fail_page_alloc}.attr, which is persistent and
> shared by all tasks. This is not what we expected, let's fix it.
>
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: 3f913fc5f974 ("mm: fix missing handler for __GFP_NOWARN")
> Reported-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
> Signed-off-by: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx>
> ---
>  v1: https://lore.kernel.org/lkml/20221107033109.59709-1-zhengqi.arch@xxxxxxxxxxxxx/
>
>  Changelog in v1 -> v2:
>   - add comment for __should_failslab() and __should_fail_alloc_page()
>     (suggested by Jason)

Looks good.

Reviewed-by: Akinobu Mita <akinobu.mita@xxxxxxxxx>