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 X-Spam-Level: X-Spam-Status: No, score=-18.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C76D2C49EB7 for ; Mon, 14 Jun 2021 11:18:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 96C21611BE for ; Mon, 14 Jun 2021 11:18:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236066AbhFNLUL (ORCPT ); Mon, 14 Jun 2021 07:20:11 -0400 Received: from mail.kernel.org ([198.145.29.99]:39540 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234235AbhFNLHx (ORCPT ); Mon, 14 Jun 2021 07:07:53 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 3437E6143B; Mon, 14 Jun 2021 10:46:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1623667569; bh=EQ6y0pZz4laLx9qhCPoyfofPdJvZrEAeH1YaFEmb3rA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LOIQZCPm8gRkv14QcyKL48IeERp/oic9AI4WCvh7MvqH6UR3EjWdmP4419ZE+JBf3 E2JIUtNmmD7hoIrvLpaDcceKPz1tHSeo0KPWX/6mvO+4MWDxtrqbWo0o0ujfiENULH JxTtRqDF3k14/9OGCI/QnqhX+eURvv46rKkHltqI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Leo Yan , Adrian Hunter , Jiri Olsa , Alexander Shishkin , Kan Liang , Mark Rutland , Namhyung Kim , Peter Zijlstra , Arnaldo Carvalho de Melo , Sasha Levin Subject: [PATCH 5.10 122/131] perf session: Correct buffer copying when peeking events Date: Mon, 14 Jun 2021 12:28:03 +0200 Message-Id: <20210614102657.164247593@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210614102652.964395392@linuxfoundation.org> References: <20210614102652.964395392@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Leo Yan [ Upstream commit 197eecb6ecae0b04bd694432f640ff75597fed9c ] When peeking an event, it has a short path and a long path. The short path uses the session pointer "one_mmap_addr" to directly fetch the event; and the long path needs to read out the event header and the following event data from file and fill into the buffer pointer passed through the argument "buf". The issue is in the long path that it copies the event header and event data into the same destination address which pointer "buf", this means the event header is overwritten. We are just lucky to run into the short path in most cases, so we don't hit the issue in the long path. This patch adds the offset "hdr_sz" to the pointer "buf" when copying the event data, so that it can reserve the event header which can be used properly by its caller. Fixes: 5a52f33adf02 ("perf session: Add perf_session__peek_event()") Signed-off-by: Leo Yan Acked-by: Adrian Hunter Acked-by: Jiri Olsa Cc: Alexander Shishkin Cc: Kan Liang Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Link: http://lore.kernel.org/lkml/20210605052957.1070720-1-leo.yan@linaro.org Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Sasha Levin --- tools/perf/util/session.c | 1 + 1 file changed, 1 insertion(+) diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c index 63b619084b34..9dddec19a494 100644 --- a/tools/perf/util/session.c +++ b/tools/perf/util/session.c @@ -1699,6 +1699,7 @@ int perf_session__peek_event(struct perf_session *session, off_t file_offset, if (event->header.size < hdr_sz || event->header.size > buf_sz) return -1; + buf += hdr_sz; rest = event->header.size - hdr_sz; if (readn(fd, buf, rest) != (ssize_t)rest) -- 2.30.2