From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-178.mta0.migadu.com (out-178.mta0.migadu.com [91.218.175.178]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1B13E1F37D8 for ; Tue, 22 Apr 2025 22:16:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.178 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745360173; cv=none; b=DjKIwU/sdEcpN1J8+1zxZL6NEPYo+wDT16DUtY6HlMZugVgNFRvkZ/WGqFyIla/jan1O+tJO1UlI1M3nKRP5xlOnHhhK7wCXRT72L3GaV3CLY6hpGk2wcmrs3uOtj1vrJyuoIQymEvnUsnYX9GujW2hJPFI9bv6K8/u5ngqLREw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745360173; c=relaxed/simple; bh=IE3neCFeH8Ltp6M5nRCbhKk2+CFGXNaRuRMA4BAHueA=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=cS+aX12T6qRzIQ7992n5DpPbDb8ObMphOTodiEBHzuZrT2X3nHVixDp/jtQbxBk0Hx5/NxezT0ohvwxhZ+mqZvPSdQ1fLgIzAl9BRHd7OrxlUeVc6uuZ5agaAufluaKcSTGBMu2G6oAbfiLDBjbkk3UhPV/rX3sotYnMZAcKtus= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=xCG/bhHn; arc=none smtp.client-ip=91.218.175.178 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="xCG/bhHn" Message-ID: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1745360160; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=BpqNkvbG+KJDxSHIgORRKjY9g4VUmpJpSov6APykpLw=; b=xCG/bhHnVpzOhulR68NdnviFXEbMixLVOUW4sLkmunjj4+7PthRHexn3MQiDQVmRTbqUsU BS9AVVqd4LlJCMtUOl1RaiAObrqMP+nKrrQD4ZIzFeAPuIlSnsLvylhlze/oOiNi1gCabJ zKZs7POUhWgFM3rEMWkKgObLcqxFRS4= Date: Tue, 22 Apr 2025 15:15:52 -0700 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH] selftests/bpf: Fix null pointer check in skb_pkt_end.c To: Prabhav Kumar Vaish Cc: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, eddyz87@gmail.com, song@kernel.org, yonghong.song@linux.dev, john.fastabend@gmail.com, kpsingh@kernel.org, sdf@fomichev.me, haoluo@google.com, jolsa@kernel.org, mykolal@fb.com, shuah@kernel.org, bpf@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org References: <20250422182331.1188338-1-pvkumar5749404@gmail.com> Content-Language: en-US X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Martin KaFai Lau In-Reply-To: <20250422182331.1188338-1-pvkumar5749404@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT On 4/22/25 11:23 AM, Prabhav Kumar Vaish wrote: > Ensure that 'tcp' is checked for NULL before dereferencing. This resolves > a potential null pointer dereference warning reported by static analysis. > > Signed-off-by: Prabhav Kumar Vaish > --- > tools/testing/selftests/bpf/progs/skb_pkt_end.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/tools/testing/selftests/bpf/progs/skb_pkt_end.c b/tools/testing/selftests/bpf/progs/skb_pkt_end.c > index 3bb4451524a1..db33ff2839f7 100644 > --- a/tools/testing/selftests/bpf/progs/skb_pkt_end.c > +++ b/tools/testing/selftests/bpf/progs/skb_pkt_end.c > @@ -45,10 +45,10 @@ int main_prog(struct __sk_buff *skb) > goto out; > > tcp = (void*)(ip + 1); > - if (tcp->dest != 0) > - goto out; > if (!tcp) This case will never be hit, so this change is not doing anything other than silencing the static checker. Take a look at commit 9cc873e85800 ("selftests/bpf: Add skb_pkt_end test"). The test was written to have a specific llvm generated code. You will need to check the generated code is still testing what it is supposed to test. pw-bot: cr > goto out; > + if (tcp->dest != 0) > + goto out; > > urg_ptr = tcp->urg_ptr; >