Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933100AbbHZAIM (ORCPT ); Tue, 25 Aug 2015 20:08:12 -0400 Received: from mail7.hitachi.co.jp ([133.145.228.42]:59035 "EHLO mail7.hitachi.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932899AbbHZAIL (ORCPT ); Tue, 25 Aug 2015 20:08:11 -0400 From: =?utf-8?B?5bmz5p2+6ZuF5bezIC8gSElSQU1BVFXvvIxNQVNBTUk=?= To: "'Wang Nan'" , "acme@kernel.org" CC: "mingo@redhat.com" , "namhyung@kernel.org" , "pi3orama@163.com" , "linux-kernel@vger.kernel.org" Subject: RE: [PATCH 1/2] perf probe: Prevent segfault when reading probe point with absolute address Thread-Topic: [PATCH 1/2] perf probe: Prevent segfault when reading probe point with absolute address Thread-Index: AQHQ3znlARQ0TFxHLEGIhG4VTWRTPZ4dZ+UQ Date: Wed, 26 Aug 2015 00:08:07 +0000 Message-ID: <50399556C9727B4D88A595C8584AAB37524EA508@GSjpTKYDCembx32.service.hitachi.net> References: <1440509256-193590-1-git-send-email-wangnan0@huawei.com> In-Reply-To: <1440509256-193590-1-git-send-email-wangnan0@huawei.com> Accept-Language: ja-JP, en-US Content-Language: ja-JP X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.198.219.51] Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by mail.home.local id t7Q08HYd021858 Content-Length: 2546 Lines: 80 > From: Wang Nan [mailto:wangnan0@huawei.com] > > 'perf probe -l' panic if there is a manually inserted probing point > with absolute address. For example: > > # echo 'p:probe/abs_ffffffff811e6615 0xffffffff811e6615' > /sys/kernel/debug/tracing/kprobe_events > # perf probe -l > Segmentation fault (core dumped) > > This patch fix this problem by considering the situation that > "tp->symbol == NULL" in find_perf_probe_point_from_dwarf() and > find_perf_probe_point_from_map(). Oops, OK this is a bug. Thanks! Acked-by: Masami Hiramatsu > > After this patch: > > # perf probe -l > probe:abs_ffffffff811e6615 (on SyS_write+5@fs/read_write.c) > > And when debug info is missing: > > # rm -rf ~/.debug > # mv /lib/modules/4.2.0-rc1+/build/vmlinux /lib/modules/4.2.0-rc1+/build/vmlinux.bak > # perf probe -l > probe:abs_ffffffff811e6615 (on sys_write+5) > > Signed-off-by: Wang Nan > Cc: Arnaldo Carvalho de Melo > Cc: Ingo Molnar > Cc: Masami Hiramatsu > Cc: Namhyung Kim > --- > tools/perf/util/probe-event.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c > index f07374b..6c7e538 100644 > --- a/tools/perf/util/probe-event.c > +++ b/tools/perf/util/probe-event.c > @@ -515,7 +515,7 @@ static int find_perf_probe_point_from_dwarf(struct probe_trace_point *tp, > if (ret < 0) > goto error; > addr += stext; > - } else { > + } else if (tp->symbol) { > addr = kernel_get_symbol_address_by_name(tp->symbol, false); > if (addr == 0) > goto error; > @@ -1815,17 +1815,17 @@ static int find_perf_probe_point_from_map(struct probe_trace_point *tp, > { > struct symbol *sym = NULL; > struct map *map; > - u64 addr; > + u64 addr = tp->address; > int ret = -ENOENT; > > if (!is_kprobe) { > map = dso__new_map(tp->module); > if (!map) > goto out; > - addr = tp->address; > sym = map__find_symbol(map, addr, NULL); > } else { > - addr = kernel_get_symbol_address_by_name(tp->symbol, true); > + if (tp->symbol) > + addr = kernel_get_symbol_address_by_name(tp->symbol, true); > if (addr) { > addr += tp->offset; > sym = __find_kernel_function(addr, &map); > -- > 1.8.3.4 ????{.n?+???????+%?????ݶ??w??{.n?+????{??G?????{ay?ʇڙ?,j??f???h?????????z_??(?階?ݢj"???m??????G????????????&???~???iO???z??v?^?m???? ????????I?