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 8745CC48BE6 for ; Mon, 14 Jun 2021 10:35:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 78FF061428 for ; Mon, 14 Jun 2021 10:35:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233527AbhFNKhL (ORCPT ); Mon, 14 Jun 2021 06:37:11 -0400 Received: from mail.kernel.org ([198.145.29.99]:39860 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233196AbhFNKea (ORCPT ); Mon, 14 Jun 2021 06:34:30 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id A0FC861245; Mon, 14 Jun 2021 10:31:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1623666715; bh=Orrf/8HQCxsdAsNoUTaVt4kXDOyRkH/lzRwD6tPRPYk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tyw01gGYYlNs6lbpJhVHWgifLNUmhd4yrswikSYnUfteleo5vksvHGM0WltbxcCCH Ezs2Du3KUOoLTvCBfragfCR+PpZE+y9q4reTWC+pdP2JgaJsGNxuKYDyopeFYvGEb3 VkosC1xUzMuE6QYegc/p04xc6weFW+tCBl0e+Aac= 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 4.9 36/42] perf session: Correct buffer copying when peeking events Date: Mon, 14 Jun 2021 12:27:27 +0200 Message-Id: <20210614102643.850989621@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210614102642.700712386@linuxfoundation.org> References: <20210614102642.700712386@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 89808ab008ad..9187d8119a75 100644 --- a/tools/perf/util/session.c +++ b/tools/perf/util/session.c @@ -1427,6 +1427,7 @@ 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