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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1C86DC433EF for ; Sat, 7 May 2022 00:51:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1445113AbiEGAyu (ORCPT ); Fri, 6 May 2022 20:54:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54028 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229608AbiEGAyr (ORCPT ); Fri, 6 May 2022 20:54:47 -0400 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AE67750B2F; Fri, 6 May 2022 17:51:02 -0700 (PDT) Received: from dggpemm500022.china.huawei.com (unknown [172.30.72.54]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4Kw81W5kmDzGpLg; Sat, 7 May 2022 08:48:15 +0800 (CST) Received: from dggpemm500019.china.huawei.com (7.185.36.180) by dggpemm500022.china.huawei.com (7.185.36.162) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Sat, 7 May 2022 08:51:00 +0800 Received: from [10.67.109.184] (10.67.109.184) by dggpemm500019.china.huawei.com (7.185.36.180) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Sat, 7 May 2022 08:51:00 +0800 Subject: Re: [PATCH bpf-next v2 1/2] bpf: Unify data extension operation of jited_ksyms and jited_linfo To: John Fastabend , , , , CC: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , =?UTF-8?B?QmrDtnJuIFTDtnBlbA==?= , Luke Nelson , Xi Wang , Martin KaFai Lau , Song Liu , Yonghong Song , KP Singh , Paul Walmsley , Palmer Dabbelt , Albert Ou References: <20220429014240.3434866-1-pulehui@huawei.com> <20220429014240.3434866-2-pulehui@huawei.com> <62758a83b512a_18fd5208b5@john.notmuch> From: Pu Lehui Message-ID: <7e1ef7a3-582b-7443-8018-69126efdc587@huawei.com> Date: Sat, 7 May 2022 08:51:00 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.8.1 MIME-Version: 1.0 In-Reply-To: <62758a83b512a_18fd5208b5@john.notmuch> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.67.109.184] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To dggpemm500019.china.huawei.com (7.185.36.180) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2022/5/7 4:52, John Fastabend wrote: > Pu Lehui wrote: >> We found that 32-bit environment can not print bpf line info due >> to data inconsistency between jited_ksyms[0] and jited_linfo[0]. >> >> For example: >> jited_kyms[0] = 0xb800067c, jited_linfo[0] = 0xffffffffb800067c >> >> We know that both of them store bpf func address, but due to the >> different data extension operations when extended to u64, they may >> not be the same. We need to unify the data extension operations of >> them. >> >> Signed-off-by: Pu Lehui >> --- >> kernel/bpf/syscall.c | 5 ++++- >> 1 file changed, 4 insertions(+), 1 deletion(-) >> >> diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c >> index e9e3e49c0eb7..18137ea5190d 100644 >> --- a/kernel/bpf/syscall.c >> +++ b/kernel/bpf/syscall.c >> @@ -3871,13 +3871,16 @@ static int bpf_prog_get_info_by_fd(struct file *file, >> info.nr_jited_line_info = 0; >> if (info.nr_jited_line_info && ulen) { >> if (bpf_dump_raw_ok(file->f_cred)) { >> + unsigned long jited_linfo_addr; >> __u64 __user *user_linfo; >> u32 i; >> >> user_linfo = u64_to_user_ptr(info.jited_line_info); >> ulen = min_t(u32, info.nr_jited_line_info, ulen); >> for (i = 0; i < ulen; i++) { >> - if (put_user((__u64)(long)prog->aux->jited_linfo[i], >> + jited_linfo_addr = (unsigned long) >> + prog->aux->jited_linfo[i]; >> + if (put_user((__u64) jited_linfo_addr, >> &user_linfo[i])) > > the logic is fine but i'm going to nitpick a bit this 4 lines is ugly > just make it slightly longer than 80chars or use a shoarter name? For > example, > > for (i = 0; i < ulen; i++) { > unsigned long l; > > l = (unsigned long) prog->aux->jited_linfo[i]; > if (put_user((__u64) l, &user_linfo[i])) > > is much nicer -- no reason to smash single assignment across multiple > lines. My $.02. > Okay, It sounds good. I will make change in next version. Thanks. > Thanks, > John > . >