From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.2 required=3.0 tests=DATE_IN_PAST_06_12, DKIMWL_WL_MED,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 31B4DC0044D for ; Sun, 15 Mar 2020 01:39:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F137020637 for ; Sun, 15 Mar 2020 01:39:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="QsE47yVs" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727054AbgCOBjo (ORCPT ); Sat, 14 Mar 2020 21:39:44 -0400 Received: from mail-qk1-f196.google.com ([209.85.222.196]:43183 "EHLO mail-qk1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726530AbgCOBjn (ORCPT ); Sat, 14 Mar 2020 21:39:43 -0400 Received: by mail-qk1-f196.google.com with SMTP id x1so15078618qkx.10 for ; Sat, 14 Mar 2020 18:39:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=ecMdX/kkcgeI1bF1MRkVwY4khKwFUay4TKuNBxqnWmk=; b=QsE47yVsnRi4mH/Ae9IkEz9gz4BC2eK+ktKXwyAIUyrPZgka87atHyWuUntrbWXx6K 5O9jjvQuM2JyWxS7EZxGwMNfx0kX2CiwRRUwjdGzEhWopOqj4hxl5eWexOQkYQg+LlCj RFIWS9yj/KRTuquJfPaLd6wjP+GeXrjxeWXW5TTb8dea50oPDfulpjvJdBwOD8Rn+6EJ dZXEf0rxId4IUN0pHvISieWW609kh+mKs5hDjbWgY/5NGf5k91QaKf8t0juiwX771QG2 jWsbyWbdOjhEkxd+2eMbaGKlMcuJsCd+M8JCJ2231jk0muQbUxR+8BMt7qy2AlZrS74/ 8AAQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=ecMdX/kkcgeI1bF1MRkVwY4khKwFUay4TKuNBxqnWmk=; b=n5nAiNBBTAlnUhIFSlBw0Ug312KRl6gvoGbrvGKaixSW+cTS4lIo4d/SKXnU8h1xKK R2bbsbEZ0Xcky5zPYDosup+daTpyRAz0efm1lx8wSYlz2AkmoasGvnbVfaQppGBXCiKD 5u+cfE3D7XNbHUoMw8+hpNFoo7lxurcCRStERRCf6gB9VHtbYaizPDMjNjwPOIKxNDFM 7poRRZwZsndEXMam4QGKHvNpyWO8W5SvVZFDLtshz6/c2p+bjMC3um/k4zt6dCC7oAhO pwYlguVjvmEHLVkAyvMbP7u3/WQQNnzgsoR+w0+yPv9mBHYMEWsQ7OXZpPnapSUSn3mV /WJw== X-Gm-Message-State: ANhLgQ0w0uev0e07M7FiunTxfQ2I3BJ0ABtyPetv9rpGjf57mnGd8CeC B9xDa5t/qowyVXpuCdWwFKSp5KeWZL2NEYAdn3pKEqwt X-Google-Smtp-Source: ADFU+vtOa6oagrl7UbWimFolLhARnqCo+lGIn00mrmW3AhyF192jiQVS5CfC0m0cO4nIO7G8SMb6EHmpHE2qlWBx0SY= X-Received: by 2002:a25:908a:: with SMTP id t10mr12174650ybl.177.1584204589078; Sat, 14 Mar 2020 09:49:49 -0700 (PDT) MIME-Version: 1.0 References: <20200314042826.166953-1-irogers@google.com> <20200314142332.GB492969@krava> In-Reply-To: <20200314142332.GB492969@krava> From: Ian Rogers Date: Sat, 14 Mar 2020 09:49:37 -0700 Message-ID: Subject: Re: [PATCH] perf mem2node: avoid double free related to realloc To: Jiri Olsa Cc: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Namhyung Kim , LKML , clang-built-linux , Stephane Eranian Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Mar 14, 2020 at 7:23 AM Jiri Olsa wrote: > > On Fri, Mar 13, 2020 at 09:28:26PM -0700, Ian Rogers wrote: > > Realloc of size zero is a free not an error, avoid this causing a double > > free. Caught by clang's address sanitizer: > > > > ==2634==ERROR: AddressSanitizer: attempting double-free on 0x6020000015f0 in thread T0: > > #0 0x5649659297fd in free llvm/llvm-project/compiler-rt/lib/asan/asan_malloc_linux.cpp:123:3 > > #1 0x5649659e9251 in __zfree tools/lib/zalloc.c:13:2 > > #2 0x564965c0f92c in mem2node__exit tools/perf/util/mem2node.c:114:2 > > #3 0x564965a08b4c in perf_c2c__report tools/perf/builtin-c2c.c:2867:2 > > #4 0x564965a0616a in cmd_c2c tools/perf/builtin-c2c.c:2989:10 > > #5 0x564965944348 in run_builtin tools/perf/perf.c:312:11 > > #6 0x564965943235 in handle_internal_command tools/perf/perf.c:364:8 > > #7 0x5649659440c4 in run_argv tools/perf/perf.c:408:2 > > #8 0x564965942e41 in main tools/perf/perf.c:538:3 > > > > 0x6020000015f0 is located 0 bytes inside of 1-byte region [0x6020000015f0,0x6020000015f1) > > freed by thread T0 here: > > #0 0x564965929da3 in realloc third_party/llvm/llvm-project/compiler-rt/lib/asan/asan_malloc_linux.cpp:164:3 > > #1 0x564965c0f55e in mem2node__init tools/perf/util/mem2node.c:97:16 > > #2 0x564965a08956 in perf_c2c__report tools/perf/builtin-c2c.c:2803:8 > > #3 0x564965a0616a in cmd_c2c tools/perf/builtin-c2c.c:2989:10 > > #4 0x564965944348 in run_builtin tools/perf/perf.c:312:11 > > #5 0x564965943235 in handle_internal_command tools/perf/perf.c:364:8 > > #6 0x5649659440c4 in run_argv tools/perf/perf.c:408:2 > > #7 0x564965942e41 in main tools/perf/perf.c:538:3 > > > > previously allocated by thread T0 here: > > #0 0x564965929c42 in calloc third_party/llvm/llvm-project/compiler-rt/lib/asan/asan_malloc_linux.cpp:154:3 > > #1 0x5649659e9220 in zalloc tools/lib/zalloc.c:8:9 > > #2 0x564965c0f32d in mem2node__init tools/perf/util/mem2node.c:61:12 > > #3 0x564965a08956 in perf_c2c__report tools/perf/builtin-c2c.c:2803:8 > > #4 0x564965a0616a in cmd_c2c tools/perf/builtin-c2c.c:2989:10 > > #5 0x564965944348 in run_builtin tools/perf/perf.c:312:11 > > #6 0x564965943235 in handle_internal_command tools/perf/perf.c:364:8 > > #7 0x5649659440c4 in run_argv tools/perf/perf.c:408:2 > > #8 0x564965942e41 in main tools/perf/perf.c:538:3 > > > > Signed-off-by: Ian Rogers > > --- > > tools/perf/util/mem2node.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/tools/perf/util/mem2node.c b/tools/perf/util/mem2node.c > > index 797d86a1ab09..7f97aa69eb65 100644 > > --- a/tools/perf/util/mem2node.c > > +++ b/tools/perf/util/mem2node.c > > @@ -95,7 +95,7 @@ int mem2node__init(struct mem2node *map, struct perf_env *env) > > > > /* Cut unused entries, due to merging. */ > > tmp_entries = realloc(entries, sizeof(*entries) * j); > > - if (tmp_entries) > > + if (j == 0 || tmp_entries) > > nice catch.. I wonder if we should fail in here, or at least > warn that there're no entris.. which is really strange ;-) The workload was the stream benchmark with perf c2c, but stream isn't particularly long running. Not sure how j became 0, there's 2 possibilities in the code. The worry with a warning is the spam, so I just wanted to make the code correct. Thanks, Ian > thanks, > jirka > > > entries = tmp_entries; > > > > for (i = 0; i < j; i++) { > > -- > > 2.25.1.481.gfbce0eb801-goog > > >