From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 05320CA0EDC for ; Wed, 20 Aug 2025 11:01:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: Content-Transfer-Encoding:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:From:References:CC:To:Subject: MIME-Version:Date:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=6MKbKfcIm7YR50vZSX1eu6n+3iJ5twsZjRooxSof3AU=; b=ilEQSlxZPMJVg+ ZPYHDFkhPdEYJrPlWdFDj6xxLLRtz9u/SfDxV3DTH2Me5aq34XXzvCSBmnFqpp3OOUoV9wZcBb4Ot hOdeks670rRLlvZM416NcqMaFFoLI8lTuIc14Wf4MeX55jFQ8KZdmfC/PNHDDyDimS+/NjNukp+D0 BzHjSs8Fx/d9yjgOhA+hTPUuvuiRze3Lbw4XI642qqrcXnXSp/6A4cCldGz/WtpPxMK2Bl53CIIoF J+bcNBQle+WFHU3SvVaHX5tBIMD/aBLZwwvrs4AnroOLcd13aFeJlKQQykFmipWmdZMAIF9p5JbTj z8/WzGU9OHsM4k+4rWGA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uogZd-0000000DGaT-1vgj; Wed, 20 Aug 2025 11:01:45 +0000 Received: from szxga05-in.huawei.com ([45.249.212.191]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1uoflo-0000000D6A4-3QVw for linux-riscv@lists.infradead.org; Wed, 20 Aug 2025 10:10:18 +0000 Received: from mail.maildlp.com (unknown [172.19.88.214]) by szxga05-in.huawei.com (SkyGuard) with ESMTP id 4c6MZD0GyLz2gL95; Wed, 20 Aug 2025 18:07:16 +0800 (CST) Received: from kwepemf100007.china.huawei.com (unknown [7.202.181.221]) by mail.maildlp.com (Postfix) with ESMTPS id 236CE1A0171; Wed, 20 Aug 2025 18:10:09 +0800 (CST) Received: from [10.67.109.184] (10.67.109.184) by kwepemf100007.china.huawei.com (7.202.181.221) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Wed, 20 Aug 2025 18:10:07 +0800 Message-ID: <239193b7-7dab-45b0-ab13-06bfe3f96f22@huawei.com> Date: Wed, 20 Aug 2025 18:10:07 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] riscv: bpf: Fix uninitialized symbol 'retval_off' Content-Language: en-US To: Chenghao Duan CC: , , , , , , , , , , , , , , , , , , , , References: <20250820062520.846720-1-duanchenghao@kylinos.cn> <8b836b6e-103a-41c2-b111-0417d8db4dce@huawei.com> <20250820092628.GA1289807@chenghao-pc> From: Pu Lehui In-Reply-To: <20250820092628.GA1289807@chenghao-pc> X-Originating-IP: [10.67.109.184] X-ClientProxiedBy: kwepems100001.china.huawei.com (7.221.188.238) To kwepemf100007.china.huawei.com (7.202.181.221) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250820_031017_046851_0894417C X-CRM114-Status: GOOD ( 15.22 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org On 2025/8/20 17:26, Chenghao Duan wrote: > On Wed, Aug 20, 2025 at 02:52:01PM +0800, Pu Lehui wrote: >> >> >> On 2025/8/20 14:25, Chenghao Duan wrote: >>> In __arch_prepare_bpf_trampoline(), retval_off is only meaningful when >>> save_ret is true, so the current logic is correct. However, in the >> >> lgtm, and same for `ip_off`, pls patch it together. > > I also checked at the time that ip_off is only initialized and assigned > when flags & BPF_TRAMP_F_IP_ARG is true. However, I noticed that the use > of ip_off also requires this condition, so the compiler did not issue a > warning. > > Chenghao > >> >>> original logic, retval_off is only initialized under certain Can you show how to replay this warning? I guess the warning path is as follow. Compiler didn't know fmod_ret prog need BPF_TRAMP_F_CALL_ORIG. ``` if (fmod_ret->nr_links) { ... emit_sd(RV_REG_FP, -retval_off, RV_REG_ZERO, ctx); } ``` >>> conditions, which may cause a build warning. >>> >>> So initialize retval_off unconditionally to fix it. >>> >>> Signed-off-by: Chenghao Duan >>> --- >>> arch/riscv/net/bpf_jit_comp64.c | 5 ++--- >>> 1 file changed, 2 insertions(+), 3 deletions(-) >>> >>> diff --git a/arch/riscv/net/bpf_jit_comp64.c b/arch/riscv/net/bpf_jit_comp64.c >>> index 10e01ff06312..49bbda8372b0 100644 >>> --- a/arch/riscv/net/bpf_jit_comp64.c >>> +++ b/arch/riscv/net/bpf_jit_comp64.c >>> @@ -1079,10 +1079,9 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, >>> stack_size += 16; >>> save_ret = flags & (BPF_TRAMP_F_CALL_ORIG | BPF_TRAMP_F_RET_FENTRY_RET); >>> - if (save_ret) { >>> + if (save_ret) >>> stack_size += 16; /* Save both A5 (BPF R0) and A0 */ >>> - retval_off = stack_size; >>> - } >>> + retval_off = stack_size; >>> stack_size += nr_arg_slots * 8; >>> args_off = stack_size; _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv