From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753945Ab1EWLGu (ORCPT ); Mon, 23 May 2011 07:06:50 -0400 Received: from mail-wy0-f174.google.com ([74.125.82.174]:54964 "EHLO mail-wy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750982Ab1EWLGi (ORCPT ); Mon, 23 May 2011 07:06:38 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=from:to:cc:subject:date:message-id:x-mailer:in-reply-to:references; b=dLwgb/sWD038aHEXwC9hpZQjBk2qb7kvL14kJVEZa4RjiohAR8UkKn8rpWmNsszos1 QxNgX25Bpm6A8Gv2veHb7BC4BZkRtebZGwx8+m1zU43C8mIKTxZxV3EeYH624HDaujo6 hT1+Z4HBrn02VgpRlOIoLeI7hNxx7jho0nr3A= From: Frederic Weisbecker To: Ingo Molnar Cc: LKML , Frederic Weisbecker , Ingo Molnar , Peter Zijlstra , Arnaldo Carvalho de Melo , Stephane Eranian Subject: [PATCH 2/2] perf tools: Fix ommitted mmap data update on remap Date: Mon, 23 May 2011 13:06:28 +0200 Message-Id: <1306148788-6179-3-git-send-email-fweisbec@gmail.com> X-Mailer: git-send-email 1.7.3.2 In-Reply-To: <1306148788-6179-1-git-send-email-fweisbec@gmail.com> References: <1306148788-6179-1-git-send-email-fweisbec@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit eac9eacee16 "perf tools: Check we are able to read the event size on mmap" brought a check to ensure we can read the size of the event before dereferencing it, and do a remap otherwise to move the buffer forward. However that remap was ommitting all the necessary work to update the new page offset, head, and to unmap previous pages, etc... To fix this, gather all the code that fetches the event in a seperate helper which does all the necessary checks about the header/event size and tells us anytime a remap is needed. Signed-off-by: Frederic Weisbecker Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Arnaldo Carvalho de Melo Cc: Stephane Eranian --- tools/perf/util/session.c | 39 ++++++++++++++++++++++++++------------- 1 files changed, 26 insertions(+), 13 deletions(-) diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c index 948327d..64500fc 100644 --- a/tools/perf/util/session.c +++ b/tools/perf/util/session.c @@ -960,6 +960,30 @@ out_err: return err; } +static union perf_event * +fetch_mmaped_event(struct perf_session *session, + u64 head, size_t mmap_size, char *buf) +{ + union perf_event *event; + + /* + * Ensure we have enough space remaining to read + * the size of the event in the headers. + */ + if (head + sizeof(event->header) > mmap_size) + return NULL; + + event = (union perf_event *)(buf + head); + + if (session->header.needs_swap) + perf_event_header__bswap(&event->header); + + if (head + event->header.size > mmap_size) + return NULL; + + return event; +} + int __perf_session__process_events(struct perf_session *session, u64 data_offset, u64 data_size, u64 file_size, struct perf_event_ops *ops) @@ -1014,19 +1038,8 @@ remap: file_pos = file_offset + head; more: - /* - * Ensure we have enough space remaining to read - * the size of the event in the headers. - */ - if (head + sizeof(event->header) > mmap_size) - goto remap; - - event = (union perf_event *)(buf + head); - - if (session->header.needs_swap) - perf_event_header__bswap(&event->header); - - if (head + event->header.size > mmap_size) { + event = fetch_mmaped_event(session, head, mmap_size, buf); + if (!event) { if (mmaps[map_idx]) { munmap(mmaps[map_idx], mmap_size); mmaps[map_idx] = NULL; -- 1.7.3.2