Date:   Wed, 1 Dec 2021 20:29:05 -0800
From:   Andrew Morton <akpm@linux-foundation.org>
To:     Bixuan Cui <cuibixuan@linux.alibaba.com>
Cc:     linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        torvalds@linux-foundation.org, leon@kernel.org, w@1wt.eu,
        keescook@chromium.org, bpf@vger.kernel.org, netdev@vger.kernel.org,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Jakub Kicinski <kuba@kernel.org>, kvm@vger.kernel.org,
        netfilter-devel@vger.kernel.org
Subject: Re: [PATCH -next] mm: delete oversized WARN_ON() in kvmalloc()
 calls
Message-Id: <20211201202905.b9892171e3f5b9a60f9da251@linux-foundation.org>
In-Reply-To: <10cb0382-012b-5012-b664-c29461ce4de8@linux.alibaba.com>
References: <1638410784-48646-1-git-send-email-cuibixuan@linux.alibaba.com>
        <20211201192643.ecb0586e0d53bf8454c93669@linux-foundation.org>
        <10cb0382-012b-5012-b664-c29461ce4de8@linux.alibaba.com>
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On Thu, 2 Dec 2021 12:05:15 +0800 Bixuan Cui <cuibixuan@linux.alibaba.com> wrote:

> 
> 在 2021/12/2 上午11:26, Andrew Morton 写道:
> >> Delete the WARN_ON() and return NULL directly for oversized parameter
> >> in kvmalloc() calls.
> >> Also add unlikely().
> >>
> >> Fixes: 7661809d493b ("mm: don't allow oversized kvmalloc() calls")
> >> Signed-off-by: Bixuan Cui<cuibixuan@linux.alibaba.com>
> >> ---
> >> There are a lot of oversize warnings and patches about kvmalloc() calls
> >> recently. Maybe these warnings are not very necessary.
> > Or maybe they are.  Please let's take a look at these warnings, one at
> > a time.  If a large number of them are bogus then sure, let's disable
> > the runtime test.  But perhaps it's the case that calling code has
> > genuine issues and should be repaired.
> Such as：

Thanks, that's helpful.

Let's bring all these to the attention of the relevant developers.

If the consensus is "the code's fine, the warning is bogus" then let's
consider retiring the warning.

If the consensus is otherwise then hopefully they will fix their stuff!


> https://syzkaller.appspot.com/bug?id=24452f89446639c901ac07379ccc702808471e8e

(cc bpf@vger.kernel.org)

> https://syzkaller.appspot.com/bug?id=f7c5a86e747f9b7ce333e7295875cd4ede2c7a0d

(cc netdev@vger.kernel.org, maintainers)

> https://syzkaller.appspot.com/bug?id=8f306f3db150657a1f6bbe1927467084531602c7

(cc kvm@vger.kernel.org)

> https://syzkaller.appspot.com/bug?id=6f30adb592d476978777a1125d1f680edfc23e00

(cc netfilter-devel@vger.kernel.org)

> https://syzkaller.appspot.com/bug?id=4c9ab8c7d0f8b551950db06559dc9cde4119ac83

(bpf again).