Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932761AbbLHFNt (ORCPT ); Tue, 8 Dec 2015 00:13:49 -0500 Received: from terminus.zytor.com ([198.137.202.10]:51156 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751175AbbLHFNr (ORCPT ); Tue, 8 Dec 2015 00:13:47 -0500 Date: Mon, 7 Dec 2015 21:13:18 -0800 From: tip-bot for Wang Nan Message-ID: Cc: hpa@zytor.com, namhyung@kernel.org, linux-kernel@vger.kernel.org, mingo@kernel.org, acme@redhat.com, wangnan0@huawei.com, lizefan@huawei.com, tglx@linutronix.de Reply-To: tglx@linutronix.de, lizefan@huawei.com, wangnan0@huawei.com, mingo@kernel.org, linux-kernel@vger.kernel.org, acme@redhat.com, namhyung@kernel.org, hpa@zytor.com In-Reply-To: <1449455746-41952-3-git-send-email-wangnan0@huawei.com> References: <1449455746-41952-3-git-send-email-wangnan0@huawei.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:perf/core] perf hists browser: Add NULL pointer check to prevent crash Git-Commit-ID: 837eeb7569bf2b3bd3b1b82e0e61edb19811036e X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2732 Lines: 79 Commit-ID: 837eeb7569bf2b3bd3b1b82e0e61edb19811036e Gitweb: http://git.kernel.org/tip/837eeb7569bf2b3bd3b1b82e0e61edb19811036e Author: Wang Nan AuthorDate: Mon, 7 Dec 2015 02:35:45 +0000 Committer: Arnaldo Carvalho de Melo CommitDate: Mon, 7 Dec 2015 12:02:11 -0300 perf hists browser: Add NULL pointer check to prevent crash Before this patch we can trigger a segfault by following steps: Step 0: Use 'perf record' to generate a perf.data without callchain Step 1: perf report Step 2: Use UP/DOWN to select an entry, don't press 'ENTER' Step 3: Use '/' to filter symbols, use a filter which returns empty result Step 4: Press 'ENTER' (notice here that the old selection is still there. This is another problem) Step 5: Press 'ENTER' to annotate that symbol Step 6: Press 'LEFT' to go out. Result: segfault: perf: Segmentation fault -------- backtrace -------- /home/wangnan/perf[0x53e568] /lib64/libc.so.6(+0x3545f)[0x7fba75d3245f] /home/wangnan/perf[0x537516] /home/wangnan/perf[0x533fef] /home/wangnan/perf[0x53b347] /home/wangnan/perf(perf_evlist__tui_browse_hists+0x96)[0x53d206] /home/wangnan/perf(cmd_report+0x1b9f)[0x442c7f] /home/wangnan/perf[0x47efa2] /home/wangnan/perf(main+0x5f5)[0x432fa5] /lib64/libc.so.6(__libc_start_main+0xf4)[0x7fba75d1ebd4] /home/wangnan/perf[0x4330d4] This is because in this case 'nd' could be NULL in ui_browser__hists_seek(), but that function never checks it. This patch adds checker for potential NULL pointer in that function. After this patch the above steps won't segfault. Signed-off-by: Wang Nan Tested-by: Arnaldo Carvalho de Melo Cc: Namhyung Kim Cc: Zefan Li Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1449455746-41952-3-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/ui/browsers/hists.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/tools/perf/ui/browsers/hists.c b/tools/perf/ui/browsers/hists.c index fa9eb92..932e13d 100644 --- a/tools/perf/ui/browsers/hists.c +++ b/tools/perf/ui/browsers/hists.c @@ -1033,6 +1033,9 @@ static void ui_browser__hists_seek(struct ui_browser *browser, * and stop when we printed enough lines to fill the screen. */ do_offset: + if (!nd) + return; + if (offset > 0) { do { h = rb_entry(nd, struct hist_entry, rb_node); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/