From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-183.mta0.migadu.com (out-183.mta0.migadu.com [91.218.175.183]) (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 059CA38B for ; Mon, 19 May 2025 00:10:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.183 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747613410; cv=none; b=tLYdgkxD7xUkDaX0+on1l0XFP1KXcXQTaczr2n55+X+B6tpeJq+VbKW83XZSLF9BLaIf8gO//4CuvMBnHaVVZyt1MoeJMVLBepCWNU4Vggjosi2MaCNjk4VYn2/vJQ4pyd3ev3D/szLZVhfX2Lxd+b3jG6Q1YAZXm/gUZ/+NPr4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747613410; c=relaxed/simple; bh=oqVlpvFxZ2oUhGtmsG5GATyuQjZ9U6PisKC1dJUH+pk=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=jVNbSXSblkEGbW3lJOtDVrDrAj+nZcZduy13ihiw23UBWZ27LGXf09gVSbDPUCII03NRrPmjJNf5qyWimFrvg1o3AjG8Utyu2FFAF2aFp1ACkJ+KLFo5O+7pFIqYMKn/fezr8oNChS3E+zPianl2zXXMQIP1pvyI6JeYmHWf01g= 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=Iyytp/QL; arc=none smtp.client-ip=91.218.175.183 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="Iyytp/QL" Message-ID: <711ce529-3a81-4f89-8c3b-43a5139190ef@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1747613403; 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=Pps3wpGlMKoYJUF44jl2urXN/r2RlMEZU71NzJUBrZA=; b=Iyytp/QL1zwq/Pch3Qd5Vj/ejZTPXmeC1daIRC0jj3XBIN4sZcMCoEY1NcecE4RIezEyQd 88GiBFR4HpWHsQ8iBiethx27RATMLU2CcyyNyJ2Kdt9G0EUumROrcRJecE6zuxapbPrh62 uUmxtC0S9kNp1IcNujF6AAUGVS4KJyk= Date: Sun, 18 May 2025 17:09:58 -0700 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH bpf-next v2 1/2] bpf: Warn with new bpf_unreachable() kfunc maybe due to uninitialized var Content-Language: en-GB To: Alexei Starovoitov Cc: bpf , Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , Kernel Team , Martin KaFai Lau References: <20250515200635.3427478-1-yonghong.song@linux.dev> <1742bbe7-7f7a-4eef-a0a9-feb2cda50bbd@linux.dev> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Yonghong Song In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT On 5/18/25 11:41 PM, Alexei Starovoitov wrote: > On Sat, May 17, 2025 at 11:14 AM Yonghong Song wrote: >> >> >> On 5/16/25 5:31 AM, Alexei Starovoitov wrote: >>> On Fri, May 16, 2025 at 2:17 PM Yonghong Song wrote: >>>> So I then decided to add an 'exit' insn after bpf_unreachable() in llvm. >>>> See latest https://github.com/llvm/llvm-project/pull/131731 (commit #2). >>>> So we won't have any control flow issues in code. With newer llvm change, >>> That's a good idea. Certainly better than special case this 'noreturn' >>> semantic in the verifier. >> Current latest llvm21 will cause kernel build failure: >> https://patchew.org/linux/20250506-default-const-init-clang-v2-1-fcfb69703264@kernel.org/ >> I will wait for the fix in bpf-next and then submit v3. > that's not going to be soon. why delay the whole thing? > submit with selftests that include inline asm and delay C only selftest. Sure. Will submit with inline asm tests soon.