From patchwork Thu Apr 19 01:34:04 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Leo Yan X-Patchwork-Id: 900489 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=linaro.org Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=linaro.org header.i=@linaro.org header.b="PaWzhRWB"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 40RM4k2gYVz9s1v for ; Thu, 19 Apr 2018 11:35:34 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753139AbeDSBfW (ORCPT ); Wed, 18 Apr 2018 21:35:22 -0400 Received: from mail-ot0-f196.google.com ([74.125.82.196]:44258 "EHLO mail-ot0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753171AbeDSBed (ORCPT ); Wed, 18 Apr 2018 21:34:33 -0400 Received: by mail-ot0-f196.google.com with SMTP id p33-v6so4100018otp.11 for ; Wed, 18 Apr 2018 18:34:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=bTeOv4ZbemmKNwy5sel+mHx//WZci0eMoeuPCgl8/r4=; b=PaWzhRWByuSB7Dg8cFgLt2fgfktHbSr/64MustDqkIIJChQhfJ+4Jn6tW2+M2qEGx+ NYwTnxtSdMu80cxgyoQHTBvj2krXy8ymf5smIx+e2VhINEpqz+3stVunQApXotCKEMHK s0ZumkMdLUkELa1i61+PHkF8lF4lzOQbEnnGY= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=bTeOv4ZbemmKNwy5sel+mHx//WZci0eMoeuPCgl8/r4=; b=ZQCFyBErkzprGRE6vpgyXrZjHat5ho1wwK06FF+F3wXwMUrRf1gLOXBzXtHw6kNL+e h31yZPgxBsDFFayufujFe4IEgMqtfXpzmvVLRhSc6NM0VaK02ykpEu3UnfZlLb9Y8t6N xk0tf9B+SrOoLGp9FgCA2lY4vClnS8hFO+5+Nyy46IfQNryXV3vikrfbebfnqNcWLeuC 2mHo1T+Iwq1ptLcDeJ6BSvPH7MI5aYAMMYVeumCctzDRdX7d69C3fTvNBhP+4HcEDiBT NGMArgmAd+AQWdVNxPEKcDApeHRmne5N9Pu9JVtFD6gx063KmkuXMpH4FFA+OStjEZxm +exw== X-Gm-Message-State: ALQs6tAMTFipENaON1ZWS3XO7eq/P4ZJp4ZPYp7VkrFprW/q7exjCBkw djW3ZUEUF85S3JNXSsJrSvOQww== X-Google-Smtp-Source: AIpwx4/EPoKbMlBl6w0peX21BOxYfW34mclKaKHdVRB4BvJDSOe7PUdDQLwPykbRNSukkFzI469ehQ== X-Received: by 2002:a9d:4442:: with SMTP id f2-v6mr2884237otj.319.1524101673003; Wed, 18 Apr 2018 18:34:33 -0700 (PDT) Received: from localhost.localdomain (li973-238.members.linode.com. [45.33.19.238]) by smtp.gmail.com with ESMTPSA id m84-v6sm1389662oia.1.2018.04.18.18.34.29 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Wed, 18 Apr 2018 18:34:32 -0700 (PDT) From: Leo Yan To: Alexei Starovoitov , Daniel Borkmann , netdev@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Leo Yan Subject: [PATCH bpf-next 3/5] samples/bpf: Use NULL for failed to find symbol Date: Thu, 19 Apr 2018 09:34:04 +0800 Message-Id: <1524101646-6544-4-git-send-email-leo.yan@linaro.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1524101646-6544-1-git-send-email-leo.yan@linaro.org> References: <1524101646-6544-1-git-send-email-leo.yan@linaro.org> Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Function ksym_search() is used to parse address and return the symbol structure, when the address is out of range for kernel symbols it returns the symbol structure of kernel '_stext' entry; this introduces confusion and it misses the chance to intuitively tell the address is out of range. This commit changes to use NULL pointer for failed to find symbol, user functions need to check the pointer is NULL and get to know the address has no corresponding kernel symbol for it. Signed-off-by: Leo Yan --- samples/bpf/bpf_load.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/samples/bpf/bpf_load.c b/samples/bpf/bpf_load.c index c2bf7ca..0c0584f 100644 --- a/samples/bpf/bpf_load.c +++ b/samples/bpf/bpf_load.c @@ -726,7 +726,7 @@ struct ksym *ksym_search(long key) /* valid ksym */ return &syms[start - 1]; - /* out of range. return _stext */ - return &syms[0]; + /* out of range. return NULL */ + return NULL; }