Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753639AbbLFSYN (ORCPT ); Sun, 6 Dec 2015 13:24:13 -0500 Received: from mx1.redhat.com ([209.132.183.28]:45008 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752937AbbLFSYL (ORCPT ); Sun, 6 Dec 2015 13:24:11 -0500 Date: Sun, 6 Dec 2015 16:24:07 -0200 From: Arnaldo Carvalho de Melo To: Namhyung Kim Cc: Wang Nan , acme@kernel.org, lizefan@huawei.com, pi3orama@163.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH] perf hists browser: Fix segfault if use symbol filter in cmdline Message-ID: <20151206182407.GB2493@redhat.com> References: <1449055732-235627-1-git-send-email-wangnan0@huawei.com> <20151202154942.GA27992@danjae.kornet> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20151202154942.GA27992@danjae.kornet> X-Url: http://acmel.wordpress.com User-Agent: Mutt/1.5.20 (2009-12-10) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2742 Lines: 86 Em Thu, Dec 03, 2015 at 12:49:42AM +0900, Namhyung Kim escreveu: > 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/ Fixed this and the 'interperted' and some other text details, and also the container_of usage as reported by you below. Thanks! - Arnaldo > > > > 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. Agreed, changing this. > 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/