From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752275AbeDKXbM (ORCPT ); Wed, 11 Apr 2018 19:31:12 -0400 Received: from lgeamrelo11.lge.com ([156.147.23.51]:36016 "EHLO lgeamrelo11.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751553AbeDKXbL (ORCPT ); Wed, 11 Apr 2018 19:31:11 -0400 X-Original-SENDERIP: 156.147.1.121 X-Original-MAILFROM: namhyung@kernel.org X-Original-SENDERIP: 10.177.227.17 X-Original-MAILFROM: namhyung@kernel.org Date: Thu, 12 Apr 2018 08:31:09 +0900 From: Namhyung Kim To: Kim Phillips Cc: Arnaldo Carvalho de Melo , Jiri Olsa , Jiri Olsa , lkml , Ingo Molnar , David Ahern , Alexander Shishkin , Peter Zijlstra , kernel-team@lge.com Subject: Re: [PATCH] Revert "perf machine: Fix paranoid check in machine__set_kernel_mmap()" Message-ID: <20180411233109.GA6320@sejong> References: <20180215122635.24029-1-jolsa@kernel.org> <20180215122635.24029-7-jolsa@kernel.org> <20180219022036.GB1583@sejong> <20180219100140.GA17630@krava> <20180219101936.GD1583@sejong> <20180219104917.GA19365@krava> <20180219121817.GC14978@kernel.org> <20180411180752.b64c4d105222fb22c159b852@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20180411180752.b64c4d105222fb22c159b852@arm.com> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, On Wed, Apr 11, 2018 at 06:07:52PM -0500, Kim Phillips wrote: > perf test 1 is failing on an arm64 box (that has a kernel module > loaded fwiw). Running bisect resulted in commit 1d12cec6ce99 "perf > machine: Fix paranoid check in machine__set_kernel_mmap()" being the > first bad commit. Reverting it fixes symbol resolution: > > # ./perf.bad record true; ./perf.bad --no-pager report --stdio --quiet > [ perf record: Woken up 1 times to write data ] > [ perf record: Captured and wrote 0.001 MB perf.data (10 samples) ] > 64.34% true [unknown] [k] 0xffff20000809ffb8 > 32.12% true [unknown] [k] 0xffff20000869f400 > 3.24% true [unknown] [k] 0xffff20000868d924 > 0.28% perf.ba [unknown] [k] 0xffff200008598b34 > 0.03% perf.ba [unknown] [k] 0xffff200008598a94 > > # ./perf.good record true; ./perf.good --no-pager report --stdio --quiet > [ perf record: Woken up 1 times to write data ] > [ perf record: Captured and wrote 0.001 MB perf.data (9 samples) ] > 91.71% true [kernel.kallsyms] [k] restore_nameidata > 7.60% true [kernel.kallsyms] [k] perf_iterate_ctx.constprop.38 > 0.69% perf.go [kernel.kallsyms] [k] perf_event_exec > > Cc: Arnaldo Carvalho de Melo > Cc: Namhyung Kim > Cc: Jiri Olsa > Cc: Ingo Molnar > Cc: David Ahern > Cc: Alexander Shishkin > Cc: Peter Zijlstra > Cc: > Fixes: 1d12cec6ce99 ("perf machine: Fix paranoid check in machine__set_kernel_mmap()") > Signed-off-by: Kim Phillips > --- > It's not clear to me what the specific intent of the original commit > was, thus the revert. Hmm.. maybe your kernel map has non-zero start and zero end. I thought it was just from an old or invalid data. But now I think that overflow can create it.. could you please show me the mmap event? $ perf script --show-mmap-events Thanks, Namhyung > > tools/perf/util/machine.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c > index 2eca8478e24f..089399139778 100644 > --- a/tools/perf/util/machine.c > +++ b/tools/perf/util/machine.c > @@ -1224,7 +1224,7 @@ static void machine__set_kernel_mmap(struct machine *machine, > * Be a bit paranoid here, some perf.data file came with > * a zero sized synthesized MMAP event for the kernel. > */ > - if (start == 0 && end == 0) > + if (machine->vmlinux_maps[i]->end == 0) > machine->vmlinux_maps[i]->end = ~0ULL; > } > } > -- > 2.17.0 >