Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755813AbbKDM1p (ORCPT ); Wed, 4 Nov 2015 07:27:45 -0500 Received: from mx1.redhat.com ([209.132.183.28]:37726 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755112AbbKDM1o (ORCPT ); Wed, 4 Nov 2015 07:27:44 -0500 Date: Wed, 4 Nov 2015 13:27:40 +0100 From: Jiri Olsa To: Markus Trippelsdorf Cc: Ingo Molnar , linux-kernel@vger.kernel.org, Peter Zijlstra , Arnaldo Carvalho de Melo , Thomas Gleixner , Andrew Morton Subject: Re: perf top segfaults on current git Message-ID: <20151104122740.GH29671@krava.brq.redhat.com> References: <20151104101533.GA332@x4> <20151104104929.GB332@x4> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20151104104929.GB332@x4> 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: 5512 Lines: 123 On Wed, Nov 04, 2015 at 11:49:30AM +0100, Markus Trippelsdorf wrote: > On 2015.11.04 at 11:15 +0100, Markus Trippelsdorf wrote: > > On 2015.11.03 at 11:02 +0100, Ingo Molnar wrote: > > > > > > Please pull the latest perf-core-for-linus git tree from: > > > > Since the current merge "perf top" segfaults on my machine: > > > > Program received signal SIGSEGV, Segmentation fault. > > > > __map__is_kernel (map=map@entry=0x1abb7a0) at util/map.c:238 > > 238 return __machine__kernel_map(map->groups->machine, map->type) == map; > > (gdb) bt > > #0 __map__is_kernel (map=map@entry=0x1abb7a0) at util/map.c:238 > > #1 0x00000000004393e4 in symbol_filter (map=map@entry=0x1abb7a0, sym=sym@entry=0x1a88560) at builtin-top.c:658 > > #2 0x00000000004fcd4d in dso__load_sym (dso=dso@entry=0x166dae0, map=map@entry=0x1abb7a0, syms_ss=0x7fffffff7680, runtime_ss=runtime_ss@entry=0x7fffffff7680, > > filter=filter@entry=0x4393c0 , kmodule=0) at util/symbol-elf.c:1082 > > #3 0x00000000004a64e0 in dso__load (dso=0x166dae0, map=map@entry=0x1abb7a0, filter=filter@entry=0x4393c0 ) at util/symbol.c:1530 > > #4 0x00000000004b941f in map__load (filter=0x4393c0 , map=) at util/map.c:289 > > #5 map__find_symbol (map=0x1abb7a0, addr=40188, filter=0x4393c0 ) at util/map.c:333 > > #6 0x00000000004803b1 in perf_event__preprocess_sample (event=event@entry=0x7ffff6a7a5f0, machine=machine@entry=0x164c7b8, al=al@entry=0x7fffffff8a90, > > sample=sample@entry=0x7fffffff8b20) at util/event.c:1045 > > #7 0x0000000000439837 in perf_event__process_sample (machine=0x164c7b8, sample=0x7fffffff8b20, evsel=0x164c320, event=0x7ffff6a7a5f0, tool=0x7fffffff8ef0) > > at builtin-top.c:737 > > #8 perf_top__mmap_read_idx (top=top@entry=0x7fffffff8ef0, idx=idx@entry=0) at builtin-top.c:870 > > #9 0x000000000043b9ef in perf_top__mmap_read (top=0x7fffffff8ef0) at builtin-top.c:887 > > #10 __cmd_top (top=0x7fffffff8ef0) at builtin-top.c:1000 > > #11 cmd_top (argc=, argv=, prefix=) at builtin-top.c:1329 > > #12 0x00000000004756b3 in run_builtin (p=p@entry=0x5b0608 , argc=argc@entry=2, argv=argv@entry=0x7fffffffe500) at perf.c:386 > > #13 0x00000000004203e2 in handle_internal_command (argv=0x7fffffffe500, argc=2) at perf.c:447 > > #14 run_argv (argv=0x7fffffffe290, argcp=0x7fffffffe29c) at perf.c:491 > > #15 main (argc=2, argv=0x7fffffffe500) at perf.c:608 > > > > It only happens occasionally (~every third or fourth run). > > Apparently it started with: > > commit cfc5acd4c80b875d2f739d6a93562034aee5563f > Author: Arnaldo Carvalho de Melo > Date: Wed Sep 23 15:15:54 2015 -0300 > > perf top: Filter symbols based on __map__is_kernel(map) > > Instead of using dso->kernel, this is equivalent at the moment, > and helps in reducing the accesses to dso->kernel. > > Cc: Adrian Hunter > Cc: Borislav Petkov > Cc: David Ahern > Cc: Frederic Weisbecker > Cc: Jiri Olsa > Cc: Namhyung Kim > Cc: Stephane Eranian > Cc: Wang Nan > Link: http://lkml.kernel.org/n/tip-1pc2v63iphtifovw3bv0bo1v@git.kernel.org > Signed-off-by: Arnaldo Carvalho de Melo > > diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c > index bdaf44f24d5d..38d4d6cac823 100644 > --- a/tools/perf/builtin-top.c > +++ b/tools/perf/builtin-top.c > @@ -655,7 +655,7 @@ static int symbol_filter(struct map *map, struct symbol *sym) > { > const char *name = sym->name; > > - if (!map->dso->kernel) > + if (!__map__is_kernel(map)) > return 0; > /* > * ppc64 uses function descriptors and appends a '.' to the > I think it's correct to assume map->groups != NULL, IMO the change just uncovered another bug I couldn't reproduce this, but I could find one place where this assumption is broken.. could you please try attached patch? thanks, jirka --- diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c index 4e38c396a897..afc6b56cf749 100644 --- a/tools/perf/util/map.c +++ b/tools/perf/util/map.c @@ -644,6 +644,12 @@ size_t map_groups__fprintf(struct map_groups *mg, FILE *fp) return printed; } +static void __map_groups__insert(struct map_groups *mg, struct map *map) +{ + __maps__insert(&mg->maps[map->type], map); + map->groups = mg; +} + static int maps__fixup_overlappings(struct maps *maps, struct map *map, FILE *fp) { struct rb_root *root; @@ -682,7 +688,7 @@ static int maps__fixup_overlappings(struct maps *maps, struct map *map, FILE *fp } before->end = map->start; - __maps__insert(maps, before); + __map_groups__insert(pos->groups, before); if (verbose >= 2) map__fprintf(before, fp); } @@ -696,7 +702,7 @@ static int maps__fixup_overlappings(struct maps *maps, struct map *map, FILE *fp } after->start = map->end; - __maps__insert(maps, after); + __map_groups__insert(pos->groups, after); if (verbose >= 2) map__fprintf(after, fp); } -- 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/