From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751601AbcFXLvS (ORCPT ); Fri, 24 Jun 2016 07:51:18 -0400 Received: from mx1.redhat.com ([209.132.183.28]:58988 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751014AbcFXLvQ (ORCPT ); Fri, 24 Jun 2016 07:51:16 -0400 Date: Fri, 24 Jun 2016 13:51:12 +0200 From: Jiri Olsa To: Marc Kleine-Budde Cc: Peter Zijlstra , Ingo Molnar , linux-kernel@vger.kernel.org, Jiri Olsa Subject: Re: [PATCH] perf: symbols: dso__load(): remove check of file on uninitialized memory Message-ID: <20160624115112.GD10142@krava> References: <1466691621-29488-1-git-send-email-mkl@pengutronix.de> <20160624064345.GB32753@krava> <0d026547-6805-fe34-3430-67ae979eed57@pengutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <0d026547-6805-fe34-3430-67ae979eed57@pengutronix.de> User-Agent: Mutt/1.6.1 (2016-04-27) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Fri, 24 Jun 2016 11:51:15 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jun 24, 2016 at 09:54:22AM +0200, Marc Kleine-Budde wrote: > On 06/24/2016 08:43 AM, Jiri Olsa wrote: > > On Thu, Jun 23, 2016 at 04:20:21PM +0200, Marc Kleine-Budde wrote: > >> In commit "403567217d3f perf symbols: Do not read symbols/data from > >> device files" a check to uninitialzied memory was added. This leads to > >> the following valgrind output: > >> > >> ==24515== Syscall param stat(file_name) points to uninitialised byte(s) > >> ==24515== at 0x75B26D5: _xstat (in /lib/x86_64-linux-gnu/libc-2.22.so) > >> ==24515== by 0x4E548D: stat (stat.h:454) > >> ==24515== by 0x4E548D: is_regular_file (util.c:687) > >> ==24515== by 0x4A5BEE: dso__load (symbol.c:1435) > >> ==24515== by 0x4BB1AE: map__load (map.c:289) > >> ==24515== by 0x4BB1AE: map__find_symbol (map.c:333) > >> ==24515== by 0x4835B3: thread__find_addr_location (event.c:1300) > >> ==24515== by 0x4B5342: add_callchain_ip (machine.c:1652) > >> ==24515== by 0x4B5342: thread__resolve_callchain_sample (machine.c:1906) > >> ==24515== by 0x4B9E7D: thread__resolve_callchain (machine.c:1958) > >> ==24515== by 0x441B3E: process_event (builtin-script.c:795) > >> ==24515== by 0x441B3E: process_sample_event (builtin-script.c:920) > >> ==24515== by 0x4BEE29: perf_evlist__deliver_sample (session.c:1192) > >> ==24515== by 0x4BEE29: machines__deliver_event (session.c:1229) > >> ==24515== by 0x4BF770: perf_session__deliver_event (session.c:1286) > >> ==24515== by 0x4BF770: ordered_events__deliver_event (session.c:114) > >> ==24515== by 0x4C1D17: __ordered_events__flush (ordered-events.c:207) > >> ==24515== by 0x4C1D17: ordered_events__flush.part.3 (ordered-events.c:274) > >> ==24515== by 0x4BF44C: perf_session__process_user_event (session.c:1325) > >> ==24515== by 0x4BF44C: perf_session__process_event (session.c:1451) > >> ==24515== Address 0x807c6a0 is 0 bytes inside a block of size 4,096 alloc'd > >> ==24515== at 0x4C29C0F: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so) > >> ==24515== by 0x4A5BCB: dso__load (symbol.c:1421) > >> ==24515== by 0x4BB1AE: map__load (map.c:289) > >> ==24515== by 0x4BB1AE: map__find_symbol (map.c:333) > >> ==24515== by 0x4835B3: thread__find_addr_location (event.c:1300) > >> ==24515== by 0x4B5342: add_callchain_ip (machine.c:1652) > >> ==24515== by 0x4B5342: thread__resolve_callchain_sample (machine.c:1906) > >> ==24515== by 0x4B9E7D: thread__resolve_callchain (machine.c:1958) > >> ==24515== by 0x441B3E: process_event (builtin-script.c:795) > >> ==24515== by 0x441B3E: process_sample_event (builtin-script.c:920) > >> ==24515== by 0x4BEE29: perf_evlist__deliver_sample (session.c:1192) > >> ==24515== by 0x4BEE29: machines__deliver_event (session.c:1229) > >> ==24515== by 0x4BF770: perf_session__deliver_event (session.c:1286) > >> ==24515== by 0x4BF770: ordered_events__deliver_event (session.c:114) > >> ==24515== by 0x4C1D17: __ordered_events__flush (ordered-events.c:207) > >> ==24515== by 0x4C1D17: ordered_events__flush.part.3 (ordered-events.c:274) > >> ==24515== by 0x4BF44C: perf_session__process_user_event (session.c:1325) > >> ==24515== by 0x4BF44C: perf_session__process_event (session.c:1451) > >> ==24515== by 0x4C0EAC: __perf_session__process_events (session.c:1804) > >> ==24515== by 0x4C0EAC: perf_session__process_events (session.c:1858) > >> > >> This patch fixes the problem by removing the check. > >> > >> Fixes: 403567217d3f perf symbols: Do not read symbols/data from device files > >> Signed-off-by: Marc Kleine-Budde > >> --- > >> tools/perf/util/symbol.c | 3 +-- > >> 1 file changed, 1 insertion(+), 2 deletions(-) > >> > >> diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c > >> index 8a747dc6cf86..b4070daeb17f 100644 > >> --- a/tools/perf/util/symbol.c > >> +++ b/tools/perf/util/symbol.c > >> @@ -1432,8 +1432,7 @@ int dso__load(struct dso *dso, struct map *map, symbol_filter_t filter) > >> * Read the build id if possible. This is required for > >> * DSO_BINARY_TYPE__BUILDID_DEBUGINFO to work > >> */ > >> - if (is_regular_file(name) && > >> - filename__read_build_id(dso->long_name, build_id, BUILD_ID_SIZE) > 0) > >> + if (filename__read_build_id(dso->long_name, build_id, BUILD_ID_SIZE) > 0) > >> dso__set_build_id(dso, build_id); > > > > ouch copy&paste error.. we better fix it properly, > > could you please check attached patch? > > The use of uninitialized memory is gone, but the "--symfs" option is > ignored: > > > stat("/lib/libpthread-2.20.so", 0x7ffe440c1270) = -1 ENOENT (No such file or directory) > > You'll look for the dso in the root file system not in the sysroot. that seems like unrelated to the 'use of uninitialized memory' issue, right? I can't see how the patch I sent could do that.. thanks, jirka