From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (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 93C126FC3 for ; Mon, 5 Jun 2023 17:26:50 +0000 (UTC) Received: from mail-pg1-x549.google.com (mail-pg1-x549.google.com [IPv6:2607:f8b0:4864:20::549]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4F22E10B for ; Mon, 5 Jun 2023 10:26:49 -0700 (PDT) Received: by mail-pg1-x549.google.com with SMTP id 41be03b00d2f7-53f6e194e7bso4524263a12.1 for ; Mon, 05 Jun 2023 10:26:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1685986008; x=1688578008; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=gI5++jso8zojBV0vx6mKi/JVB3NStV9TzsSq8gpkyGA=; b=PSwb4y32X+7AX397LSBZScP3Tf2M7xCGNFdQmHQr9VKemE8hVL+QDGlKh+EBEdBIot paGsVJwM1q9ohix7Fl1ICi9rNp1cpN7X/So5fNTRn7CjJxfKGx8MQpk6E7LdLUaLJzdd yvrnI2CbMfwqB4YiSNDB7datL+0i9c3OZP4yPpiYH4TExE7A209nlepyNBSXyTfbUVWb 1kyqHHHc5b+EuaMkhMaXzK5L8VbGVLP6Ly6ubQ1VWwTmhNo+gHIgQkrbN5HteXwJhfE8 lIWsJ5sgQ/+DC7JLi1cqKzf4crOks92AaVcxmV98G3gafZC5VOF4zfZ1HNW3o8GGRSNH zeHA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1685986008; x=1688578008; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=gI5++jso8zojBV0vx6mKi/JVB3NStV9TzsSq8gpkyGA=; b=Qf4xrVauXY7UUyj4U54oh6eIxG57PIA4b6df+vwWBbC8IX+84VGAHDa9N1oHO08saW Riaq4hhP/sMCOhp4x53hIx8epr5znJYkaVqG2/SrVwEB6esuD+I8GIhFM7nb9hqCDLBp wPekwaxF2SNO2LTSHEn57NiX0UzfD1E81+YgWzhZ8+b4pK/XDYoWEztFuBLxsH9OFb63 tB4YQth6AkXHBLIIL6QbsZRsSDvqdXbPc1eXhANdjufXMKhSdvt4pN8Dofu1mXeWNtSD Ub6OpvTAjlA27GZnfQG0ShToUhH0fejLcUrNB1Whx9D3Xuzd6t3pSgt1hWvnVSRiVmDW nTWg== X-Gm-Message-State: AC+VfDwT/j7lhYmtV3IXxIIq2xXYOuwB/JucGuzep6ENN0Lp+oMLndZ+ 9m35hOOVXahqlJMhvQiod9vXS6A= X-Google-Smtp-Source: ACHHUZ7jBorG0N5niR51/rjKQ02tEOhsYvW3GusoQqySYItyHe2yyK+9rICJCRfVrzhy+Jm09OGOWcs= X-Received: from sdf.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5935]) (user=sdf job=sendgmr) by 2002:a63:1542:0:b0:50c:a00:c1fa with SMTP id 2-20020a631542000000b0050c0a00c1famr85783pgv.7.1685986008448; Mon, 05 Jun 2023 10:26:48 -0700 (PDT) Date: Mon, 5 Jun 2023 10:26:46 -0700 In-Reply-To: <20230605033449.239123-1-liuxin350@huawei.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20230605033449.239123-1-liuxin350@huawei.com> Message-ID: Subject: Re: [PATCH] libbpf:fix use empty function pointers in ringbuf_poll From: Stanislav Fomichev To: Xin Liu Cc: daniel@iogearbox.net, andrii@kernel.org, ast@kernel.org, bpf@vger.kernel.org, davem@davemloft.net, edumazet@google.com, hsinweih@uci.edu, jakub@cloudflare.com, john.fastabend@gmail.com, kuba@kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, pabeni@redhat.com, syzbot+49f6cef45247ff249498@syzkaller.appspotmail.com, syzkaller-bugs@googlegroups.com, yanan@huawei.com, wuchangye@huawei.com, xiesongyang@huawei.com, kongweibin2@huawei.com, zhangmingyi5@huawei.com Content-Type: text/plain; charset="utf-8" X-Spam-Status: No, score=-9.6 required=5.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE,USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net On 06/05, Xin Liu wrote: > From: zhangmingyi > > The sample_cb of the ring_buffer__new interface can transfer NULL. However, > the system does not check whether sample_cb is NULL during > ring_buffer__poll, null pointer is used. What is the point of calling ring_buffer__new with sample_cb == NULL?