linux-kernel - Re: [PATCH] slub: untag object before slab end

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Message-ID: <eeac3e54-c31a-a583-b185-b2d36d7debed@iki.fi>
Date:   Wed, 13 Feb 2019 09:32:32 +0200
From:   Pekka Enberg <penberg@....fi>
To:     Qian Cai <cai@....pw>, akpm@...ux-foundation.org, cl@...ux.com,
        penberg@...nel.org, rientjes@...gle.com, iamjoonsoo.kim@....com
Cc:     andreyknvl@...gle.com, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] slub: untag object before slab end



On 13/02/2019 4.05, Qian Cai wrote:
> get_freepointer() could return NULL if there is no more free objects in
> the slab. However, it could return a tagged pointer (like
> 0x2200000000000000) with KASAN_SW_TAGS which would escape the NULL
> object checking in check_valid_pointer() and trigger errors below, so
> untag the object before checking for a NULL object there.

Reviewed-by: Pekka Enberg <penberg@...nel.org>