Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753078AbcJKJ2s (ORCPT ); Tue, 11 Oct 2016 05:28:48 -0400 Received: from sub5.mail.dreamhost.com ([208.113.200.129]:50442 "EHLO homiemail-a94.g.dreamhost.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753016AbcJKJ2q (ORCPT ); Tue, 11 Oct 2016 05:28:46 -0400 Date: Tue, 11 Oct 2016 02:28:39 -0700 From: Krister Johansen To: Namhyung Kim Cc: Arnaldo Carvalho de Melo , Masami Hiramatsu , =?utf-8?B?RnLDqWTDqXJpYw==?= Weisbecker , linux-kernel@vger.kernel.org Subject: [PATCH v2 perf/core] perf script: fix a use after free crash. Message-ID: <20161011092839.GC7837@templeofstupid.com> References: <20161007022200.GB31113@sejong> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20161007022200.GB31113@sejong> 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: 4049 Lines: 139 If dso__load_kcore frees all of the existing maps, but one has already been attached to a callchain cursor node, then we can get a SIGSEGV in any function that happens to try to use this invalid cursor. Use the existing map refcount mechanism to forestall cleanup of a map until the cursor iterates past the node. Signed-off-by: Krister Johansen --- tools/perf/util/callchain.c | 13 +++++++++++-- tools/perf/util/callchain.h | 6 ++++++ tools/perf/util/hist.c | 2 ++ 3 files changed, 19 insertions(+), 2 deletions(-) diff --git a/tools/perf/util/callchain.c b/tools/perf/util/callchain.c index 07fd30b..002bf5d 100644 --- a/tools/perf/util/callchain.c +++ b/tools/perf/util/callchain.c @@ -439,7 +439,7 @@ fill_node(struct callchain_node *node, struct callchain_cursor *cursor) } call->ip = cursor_node->ip; call->ms.sym = cursor_node->sym; - call->ms.map = cursor_node->map; + call->ms.map = map__get(cursor_node->map); list_add_tail(&call->list, &node->val); callchain_cursor_advance(cursor); @@ -464,6 +464,7 @@ add_child(struct callchain_node *parent, list_for_each_entry_safe(call, tmp, &new->val, list) { list_del(&call->list); + map__zput(call->ms.map); free(call); } free(new); @@ -732,6 +733,7 @@ merge_chain_branch(struct callchain_cursor *cursor, callchain_cursor_append(cursor, list->ip, list->ms.map, list->ms.sym); list_del(&list->list); + map__zput(list->ms.map); free(list); } @@ -780,7 +782,8 @@ int callchain_cursor_append(struct callchain_cursor *cursor, } node->ip = ip; - node->map = map; + map__zput(node->map); + node->map = map__get(map); node->sym = sym; cursor->nr++; @@ -830,6 +833,8 @@ int fill_callchain_info(struct addr_location *al, struct callchain_cursor_node * goto out; } + map__get(al->map); + if (al->map->groups == &al->machine->kmaps) { if (machine__is_host(al->machine)) { al->cpumode = PERF_RECORD_MISC_KERNEL; @@ -947,11 +952,13 @@ static void free_callchain_node(struct callchain_node *node) list_for_each_entry_safe(list, tmp, &node->parent_val, list) { list_del(&list->list); + map__zput(list->ms.map); free(list); } list_for_each_entry_safe(list, tmp, &node->val, list) { list_del(&list->list); + map__zput(list->ms.map); free(list); } @@ -1015,6 +1022,7 @@ int callchain_node__make_parent_list(struct callchain_node *node) goto out; *new = *chain; new->has_children = false; + map__get(new->ms.map); list_add_tail(&new->list, &head); } parent = parent->parent; @@ -1035,6 +1043,7 @@ int callchain_node__make_parent_list(struct callchain_node *node) out: list_for_each_entry_safe(chain, new, &head, list) { list_del(&chain->list); + map__zput(chain->ms.map); free(chain); } return -ENOMEM; diff --git a/tools/perf/util/callchain.h b/tools/perf/util/callchain.h index 13e7554..798ba81 100644 --- a/tools/perf/util/callchain.h +++ b/tools/perf/util/callchain.h @@ -5,6 +5,7 @@ #include #include #include "event.h" +#include "map.h" #include "symbol.h" #define HELP_PAD "\t\t\t\t" @@ -178,8 +179,13 @@ int callchain_merge(struct callchain_cursor *cursor, */ static inline void callchain_cursor_reset(struct callchain_cursor *cursor) { + struct callchain_cursor_node *node; + cursor->nr = 0; cursor->last = &cursor->first; + + for (node = cursor->first; node != NULL; node = node->next) + map__zput(node->map); } int callchain_cursor_append(struct callchain_cursor *cursor, u64 ip, diff --git a/tools/perf/util/hist.c b/tools/perf/util/hist.c index b02992e..609b365 100644 --- a/tools/perf/util/hist.c +++ b/tools/perf/util/hist.c @@ -1,6 +1,7 @@ #include "util.h" #include "build-id.h" #include "hist.h" +#include "map.h" #include "session.h" #include "sort.h" #include "evlist.h" @@ -979,6 +980,7 @@ iter_finish_cumulative_entry(struct hist_entry_iter *iter, { zfree(&iter->priv); iter->he = NULL; + map__zput(al->map); return 0; } -- 2.7.4