Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752181AbbKKHDI (ORCPT ); Wed, 11 Nov 2015 02:03:08 -0500 Received: from szxga02-in.huawei.com ([119.145.14.65]:36343 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751205AbbKKHDG (ORCPT ); Wed, 11 Nov 2015 02:03:06 -0500 Message-ID: <5642E80B.4050101@huawei.com> Date: Wed, 11 Nov 2015 15:02:35 +0800 From: "Wangnan (F)" User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:31.0) Gecko/20100101 Thunderbird/31.6.0 MIME-Version: 1.0 To: Adrian Hunter , Arnaldo Carvalho de Melo CC: , , , , , Subject: Re: [PATCH] perf symbols/KCORE: Rebuild rbtree when adjusting symbols for kcore References: <1446803172-83107-1-git-send-email-wangnan0@huawei.com> <20151106131950.GA13236@kernel.org> <563CB241.2090701@intel.com> In-Reply-To: <563CB241.2090701@intel.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.111.66.109] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020202.5642E81D.00D6,ss=1,re=0.000,fgs=0, ip=0.0.0.0, so=2013-06-18 04:22:30, dmn=2011-05-27 18:58:46 X-Mirapoint-Loop-Id: 481be537caa1a2f8cd552ee039ceed85 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3542 Lines: 109 On 2015/11/6 21:59, Adrian Hunter wrote: > On 06/11/15 15:19, Arnaldo Carvalho de Melo wrote: >> Em Fri, Nov 06, 2015 at 09:46:12AM +0000, Wang Nan escreveu: >>> In dso__split_kallsyms_for_kcore(), current code adjusts symbol's >>> address but only reinsert it into rbtree if the symbol belongs to >>> another map. However, the expression for adjusting symbol (pos->start -= >>> curr_map->start - curr_map->pgoff) can change the relative order between >>> two symbols (even if the affected symbols are in different maps, in >>> kcore case they are possible to share one same dso), which damages the >>> rbtree. >> Right, some code does change the symbol values it gets from whatever >> symtab (kallsyms, ELF, JIT maps, etc) when it should instead use the per >> map data structure (struct map) and its ->{map,unmap}_ip, ->pgoff, >> ->reloc, members for that :-\ >> >> I.e. 'struct dso' should be just what comes from the symtab, while >> 'struct map' should be about where that DSO is in memory. >> >> With that in mind, do you still think your fix is the correct one? >> >> Adrian? > The problem is when the order in memory (in kallsyms) is different > to the order on the dso (kcore). > > I think to make it more general it needs to insert to a new tree. > e.g. > I have tested this patch and it works for me. Thank you. > diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c > index b4cc7662677e..09343a880c0b 100644 > --- a/tools/perf/util/symbol.c > +++ b/tools/perf/util/symbol.c > @@ -654,19 +654,24 @@ static int dso__split_kallsyms_for_kcore(struct dso *dso, struct map *map, > struct map_groups *kmaps = map__kmaps(map); > struct map *curr_map; > struct symbol *pos; > - int count = 0, moved = 0; > + int count = 0; > + struct rb_root old_root = dso->symbols[map->type]; > struct rb_root *root = &dso->symbols[map->type]; > struct rb_node *next = rb_first(root); > > if (!kmaps) > return -1; > > + *root = RB_ROOT; > + > while (next) { > char *module; > > pos = rb_entry(next, struct symbol, rb_node); > next = rb_next(&pos->rb_node); > > + rb_erase_init(&pos->rb_node, &old_root); > + > module = strchr(pos->name, '\t'); > if (module) > *module = '\0'; > @@ -674,28 +679,21 @@ static int dso__split_kallsyms_for_kcore(struct dso *dso, struct map *map, > curr_map = map_groups__find(kmaps, map->type, pos->start); > > if (!curr_map || (filter && filter(curr_map, pos))) { > - rb_erase_init(&pos->rb_node, root); > symbol__delete(pos); > - } else { > - pos->start -= curr_map->start - curr_map->pgoff; > - if (pos->end) > - pos->end -= curr_map->start - curr_map->pgoff; > - if (curr_map->dso != map->dso) { > - rb_erase_init(&pos->rb_node, root); > - symbols__insert( > - &curr_map->dso->symbols[curr_map->type], > - pos); > - ++moved; > - } else { > - ++count; > - } > + continue; > } > + > + pos->start -= curr_map->start - curr_map->pgoff; > + if (pos->end) > + pos->end -= curr_map->start - curr_map->pgoff; > + symbols__insert(&curr_map->dso->symbols[curr_map->type], pos); > + ++count; > } > > /* Symbols have been adjusted */ > dso->adjust_symbols = 1; > > - return count + moved; > + return count; > } > > /* > -- 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/