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Date:   Tue, 18 Oct 2022 22:37:07 -0700
From:   Kees Cook <keescook@chromium.org>
To:     Andrew Morton <akpm@linux-foundation.org>
Cc:     linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        linux-hardening@vger.kernel.org
Subject: Re: [PATCH] mempool: Use kmalloc_size_roundup() to match ksize()
 usage
Message-ID: <202210182235.3B19DFCB28@keescook>
References: <20221018090323.never.897-kees@kernel.org>
 <20221018155137.f6898d165aade2e3a5f0b2d3@linux-foundation.org>
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On Tue, Oct 18, 2022 at 03:51:37PM -0700, Andrew Morton wrote:
> On Tue, 18 Oct 2022 02:03:29 -0700 Kees Cook <keescook@chromium.org> wrote:
> 
> > Round up allocations with kmalloc_size_roundup() so that mempool's use
> > of ksize() is always accurate and no special handling of the memory is
> > needed by KASAN, UBSAN_BOUNDS, nor FORTIFY_SOURCE.
> 
> Confused.  If the special handling is not needed, why doesn't the patch
> removed the no longer needed special handling?

The special handling is in the ksize() implementation, so it can't be
removed[1] until all the ksize()-affected users are updated to see their
true allocation sizes first.

[1] https://lore.kernel.org/lkml/20220923202822.2667581-16-keescook@chromium.org/

-- 
Kees Cook