Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932996AbbLBPuU (ORCPT ); Wed, 2 Dec 2015 10:50:20 -0500 Received: from mail-pa0-f45.google.com ([209.85.220.45]:35839 "EHLO mail-pa0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932703AbbLBPuP (ORCPT ); Wed, 2 Dec 2015 10:50:15 -0500 Date: Thu, 3 Dec 2015 00:49:42 +0900 From: Namhyung Kim To: Wang Nan Cc: acme@kernel.org, lizefan@huawei.com, pi3orama@163.com, linux-kernel@vger.kernel.org, Arnaldo Carvalho de Melo Subject: Re: [PATCH] perf hists browser: Fix segfault if use symbol filter in cmdline Message-ID: <20151202154942.GA27992@danjae.kornet> References: <1449055732-235627-1-git-send-email-wangnan0@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <1449055732-235627-1-git-send-email-wangnan0@huawei.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2372 Lines: 76 Hi, On Wed, Dec 02, 2015 at 11:28:52AM +0000, Wang Nan wrote: > If feed perf a symbol filter in cmdline and the result is empty, > pressing 'Enter' in the hist browser causes crash: > > # ./perf report perf.data <-- Common mistake for beginners > > Then press 'Enter': > > perf: Segmentation fault > -------- backtrace -------- > /home/wangnan/perf[0x53e578] > /lib64/libc.so.6(+0x3545f)[0x7f76bafe045f] > /home/wangnan/perf[0x539dd4] > /home/wangnan/perf(perf_evlist__tui_browse_hists+0x96)[0x53d216] > /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)[0x7f76bafccbd4] > /home/wangnan/perf[0x4330d4] > > This is because 'perf.data' is interperted as a symbol filter, and the > result is empty, so selection is empty. However, > hist_browser__toggle_fold() forgets to check it. > > This patch simply return faluse when selection is NULL. s/faluse/false/ > > Signed-off-by: Wang Nan > Cc: Arnaldo Carvalho de Melo Acked-by: Namhyung Kim One nitpick below.. > --- > tools/perf/ui/browsers/hists.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/tools/perf/ui/browsers/hists.c b/tools/perf/ui/browsers/hists.c > index dcdcbaf..33da341 100644 > --- a/tools/perf/ui/browsers/hists.c > +++ b/tools/perf/ui/browsers/hists.c > @@ -337,9 +337,12 @@ static bool hist_browser__toggle_fold(struct hist_browser *browser) > { > struct hist_entry *he = browser->he_selection; > struct map_symbol *ms = browser->selection; > - struct callchain_list *cl = container_of(ms, struct callchain_list, ms); > + struct callchain_list *cl = ms ? container_of(ms, struct callchain_list, ms) : NULL; I think this line is not needed as container_of doesn't make a pointer dereference by itself. Just checking below is enough IMHO. Thanks, Namhyung > bool has_children; > > + if (!ms) > + return false; > + > if (ms == &he->ms) > has_children = hist_entry__toggle_fold(he); > else > -- > 1.8.3.4 > -- 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/