linux-kernel - Re: [PATCH] mm/slub, kasan: fix checking page

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Message-ID: <CALvZod6d=Ri1K-cZMi_6MXuDnoRPdz5mCPN6DXRB8YyotV6d2w@mail.gmail.com>
Date:   Tue, 10 Aug 2021 17:17:53 -0700
From:   Shakeel Butt <shakeelb@...gle.com>
To:     andrey.konovalov@...ux.dev
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        Andrey Konovalov <andreyknvl@...il.com>,
        kasan-dev@...glegroups.com, Linux MM <linux-mm@...ck.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] mm/slub, kasan: fix checking page_alloc allocations on free

On Tue, Aug 10, 2021 at 4:47 PM <andrey.konovalov@...ux.dev> wrote:
>
> From: Andrey Konovalov <andreyknvl@...il.com>
>
> A fix for stat counters f227f0faf63b ("slub: fix unreclaimable slab stat
> for bulk free") used page_address(page) as kfree_hook() argument instead
> of object. While the change is technically correct, it breaks KASAN's
> ability to detect improper (unaligned) pointers passed to kfree() and
> causes the kmalloc_pagealloc_invalid_free test to fail.
>
> This patch changes free_nonslab_page() to pass object to kfree_hook()
> instead of page_address(page) as it was before the fix.
>
> Fixed: f227f0faf63b ("slub: fix unreclaimable slab stat for bulk free")
> Signed-off-by: Andrey Konovalov <andreyknvl@...il.com>

The fix is already in the mm tree:
https://lkml.kernel.org/r/20210802180819.1110165-1-shakeelb@google.com