From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.loongson.cn (mail.loongson.cn [114.242.206.163]) by smtp.subspace.kernel.org (Postfix) with ESMTP id B75E82877C0 for ; Tue, 26 Aug 2025 07:08:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=114.242.206.163 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756192104; cv=none; b=pBPIJYQuO+VTgD5KGtsmUrBD7yyqomhfAWr6wBvZ9ZJEsCjp9nOBixaihi0qd0qDxh7BdjP80FCBpy3UEZvycAOUIvX5ZNefopxkpcfLAW+nEZptPpSj8Kix7+COMJ9/31oD9mX73ARZjMoZE4m9wgEMOm1EfduS/mIwejpwCps= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756192104; c=relaxed/simple; bh=OVE9hGqVcrmr2QU6izD836shHsGG1g38C4ChzAfeGaI=; h=Subject:To:Cc:References:From:Message-ID:Date:MIME-Version: In-Reply-To:Content-Type; b=YlXhrEmoVU1bcwU2wgExyzY+jWzgimPG0Wy16tNfiBiPp4O2CtPDA5UfVwVEYtPAzQvjAPns/67IUxE+bz05oheUi7cJrTuWGRG+h4pbrF3BmrDB8rwFVJ76yBw4cUbSBjacuwFAc8x4JMBYlYA6hKMStWFmHbJEGDM9kEopsvg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=loongson.cn; spf=pass smtp.mailfrom=loongson.cn; arc=none smtp.client-ip=114.242.206.163 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=loongson.cn Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=loongson.cn Received: from loongson.cn (unknown [113.200.148.30]) by gateway (Coremail) with SMTP id _____8Dxvr9iXa1oEEMDAA--.5298S3; Tue, 26 Aug 2025 15:08:18 +0800 (CST) Received: from [10.130.10.66] (unknown [113.200.148.30]) by front1 (Coremail) with SMTP id qMiowJAxfcFfXa1oQ3RpAA--.11172S3; Tue, 26 Aug 2025 15:08:15 +0800 (CST) Subject: Re: [PATCH] LoongArch: BPF: Fix uninitialized symbol 'retval_off' To: Huacai Chen , Alexei Starovoitov , Daniel Borkmann , John Fastabend Cc: bpf@vger.kernel.org, Hengqi Chen , Huacai Chen , George Guo , Chenghao Duan , loongarch@lists.linux.dev, kernel test robot , Dan Carpenter References: <20250819111953.3197428-1-chenhuacai@loongson.cn> From: Tiezhu Yang Message-ID: <1378057e-4fc1-2bcd-4d60-1a10bd98e5bb@loongson.cn> Date: Tue, 26 Aug 2025 15:07:10 +0800 User-Agent: Mozilla/5.0 (X11; Linux loongarch64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In-Reply-To: <20250819111953.3197428-1-chenhuacai@loongson.cn> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-CM-TRANSID:qMiowJAxfcFfXa1oQ3RpAA--.11172S3 X-CM-SenderInfo: p1dqw3xlh2x3gn0dqz5rrqw2lrqou0/ X-Coremail-Antispam: 1Uk129KBj93XoW7AFW7Jr15CFWDGrWktFy3ZFc_yoW8Wr13pr ZrZrnIyF48Wry2qa9rX3yrXrn0qr4DGrnxWF1YyFyrCay5Xw1vvr1rGa98WFyjy39Yvw10 qrs0krnIk3ZrAacCm3ZEXasCq-sJn29KB7ZKAUJUUUUx529EdanIXcx71UUUUU7KY7ZEXa sCq-sGcSsGvfJ3Ic02F40EFcxC0VAKzVAqx4xG6I80ebIjqfuFe4nvWSU5nxnvy29KBjDU 0xBIdaVrnRJUUUPYb4IE77IF4wAFF20E14v26r1j6r4UM7CY07I20VC2zVCF04k26cxKx2 IYs7xG6rWj6s0DM7CIcVAFz4kK6r1Y6r17M28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48v e4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_Xr0_Ar1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI 0_Gr0_Cr1l84ACjcxK6I8E87Iv67AKxVW0oVCq3wA2z4x0Y4vEx4A2jsIEc7CjxVAFwI0_ GcCE3s1ln4kS14v26r126r1DM2AIxVAIcxkEcVAq07x20xvEncxIr21l57IF6xkI12xvs2 x26I8E6xACxx1l5I8CrVACY4xI64kE6c02F40Ex7xfMcIj6xIIjxv20xvE14v26r126r1D McIj6I8E87Iv67AKxVW8JVWxJwAm72CE4IkC6x0Yz7v_Jr0_Gr1lF7xvr2IY64vIr41lc7 I2V7IY0VAS07AlzVAYIcxG8wCY1x0262kKe7AKxVWUAVWUtwCF04k20xvY0x0EwIxGrwCF x2IqxVCFs4IE7xkEbVWUJVW8JwCFI7km07C267AKxVWUAVWUtwC20s026c02F40E14v26r 1j6r18MI8I3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_Jw0_GFylIxkGc2Ij 64vIr41lIxAIcVC0I7IYx2IY67AKxVWUCVW8JwCI42IY6xIIjxv20xvEc7CjxVAFwI0_Jr 0_Gr1lIxAIcVCF04k26cxKx2IYs7xG6r1j6r1xMIIF0xvEx4A2jsIE14v26r4j6F4UMIIF 0xvEx4A2jsIEc7CjxVAFwI0_Gr0_Gr1UYxBIdaVFxhVjvjDU0xZFpf9x07jFApnUUUUU= On 2025/8/19 下午7:19, Huacai Chen wrote: > In __arch_prepare_bpf_trampoline(), retval_off is meaningful only when > save_ret is not 0, so the current logic is correct. But it may cause a > build warning: > > arch/loongarch/net/bpf_jit.c:1547 __arch_prepare_bpf_trampoline() error: uninitialized symbol 'retval_off'. > > So initialize retval_off unconditionally to fix it. > > Fixes: f9b6b41f0cf3 ("LoongArch: BPF: Add basic bpf trampoline support") > Closes: https://lore.kernel.org/r/202508191020.PBBh07cK-lkp@intel.com/ > Reported-by: kernel test robot > Reported-by: Dan Carpenter > Signed-off-by: Huacai Chen > --- > arch/loongarch/net/bpf_jit.c | 9 ++++----- > 1 file changed, 4 insertions(+), 5 deletions(-) > > diff --git a/arch/loongarch/net/bpf_jit.c b/arch/loongarch/net/bpf_jit.c > index abfdb6bb5c38..a73f6ea4ed4a 100644 > --- a/arch/loongarch/net/bpf_jit.c > +++ b/arch/loongarch/net/bpf_jit.c > @@ -1504,11 +1504,10 @@ static int __arch_prepare_bpf_trampoline(struct jit_ctx *ctx, struct bpf_tramp_i > stack_size += 16; > > save_ret = flags & (BPF_TRAMP_F_CALL_ORIG | BPF_TRAMP_F_RET_FENTRY_RET); > - if (save_ret) { > - /* Save BPF R0 and A0 */ > - stack_size += 16; > - retval_off = stack_size; > - } > + if (save_ret) > + stack_size += 16; /* Save BPF R0 and A0 */ > + > + retval_off = stack_size; Just init retval_off as 0 at the beginning of this function? What is the difference? which is better? Thanks, Tiezhu