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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8F48EC46467 for ; Thu, 15 Dec 2022 12:34:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229536AbiLOMeU (ORCPT ); Thu, 15 Dec 2022 07:34:20 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51260 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229668AbiLOMeL (ORCPT ); Thu, 15 Dec 2022 07:34:11 -0500 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D1A711C925; Thu, 15 Dec 2022 04:34:08 -0800 (PST) Received: from dggpemm500006.china.huawei.com (unknown [172.30.72.53]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4NXs4X0sYrzgZ3Z; Thu, 15 Dec 2022 20:29:48 +0800 (CST) Received: from [10.174.178.55] (10.174.178.55) by dggpemm500006.china.huawei.com (7.185.36.236) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.34; Thu, 15 Dec 2022 20:34:05 +0800 Subject: Re: [PATCH v9] kallsyms: Add self-test facility To: Geert Uytterhoeven CC: Josh Poimboeuf , Jiri Kosina , Miroslav Benes , Petr Mladek , Joe Lawrence , , , Masahiro Yamada , Alexei Starovoitov , Jiri Olsa , Kees Cook , Andrew Morton , Luis Chamberlain , , Steven Rostedt , Ingo Molnar , David Laight , linux-m68k References: <20221115083349.1662-1-thunder.leizhen@huawei.com> From: "Leizhen (ThunderTown)" Message-ID: Date: Thu, 15 Dec 2022 20:33:53 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 MIME-Version: 1.0 In-Reply-To: Content-Type: multipart/mixed; boundary="------------6C44F0A13F580239C62817B7" Content-Language: en-US X-Originating-IP: [10.174.178.55] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To dggpemm500006.china.huawei.com (7.185.36.236) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: live-patching@vger.kernel.org --------------6C44F0A13F580239C62817B7 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit On 2022/12/15 17:39, Geert Uytterhoeven wrote: > Hi Zhen, > > On Thu, Dec 15, 2022 at 10:16 AM Leizhen (ThunderTown) > wrote: >> On 2022/12/15 16:50, Geert Uytterhoeven wrote: >>> On Tue, Nov 15, 2022 at 9:41 AM Zhen Lei wrote: >>>> Added test cases for basic functions and performance of functions >>>> kallsyms_lookup_name(), kallsyms_on_each_symbol() and >>>> kallsyms_on_each_match_symbol(). It also calculates the compression rate >>>> of the kallsyms compression algorithm for the current symbol set. >>>> >>>> The basic functions test begins by testing a set of symbols whose address >>>> values are known. Then, traverse all symbol addresses and find the >>>> corresponding symbol name based on the address. It's impossible to >>>> determine whether these addresses are correct, but we can use the above >>>> three functions along with the addresses to test each other. Due to the >>>> traversal operation of kallsyms_on_each_symbol() is too slow, only 60 >>>> symbols can be tested in one second, so let it test on average once >>>> every 128 symbols. The other two functions validate all symbols. >>>> >>>> If the basic functions test is passed, print only performance test >>>> results. If the test fails, print error information, but do not perform >>>> subsequent performance tests. >>>> >>>> Start self-test automatically after system startup if >>>> CONFIG_KALLSYMS_SELFTEST=y. >>>> >>>> Example of output content: (prefix 'kallsyms_selftest:' is omitted >>>> start >>>> --------------------------------------------------------- >>>> | nr_symbols | compressed size | original size | ratio(%) | >>>> |---------------------------------------------------------| >>>> | 107543 | 1357912 | 2407433 | 56.40 | >>>> --------------------------------------------------------- >>>> kallsyms_lookup_name() looked up 107543 symbols >>>> The time spent on each symbol is (ns): min=630, max=35295, avg=7353 >>>> kallsyms_on_each_symbol() traverse all: 11782628 ns >>>> kallsyms_on_each_match_symbol() traverse all: 9261 ns >>>> finish >>>> >>>> Signed-off-by: Zhen Lei >>> >>> Thanks for your patch, which is now commit 30f3bb09778de64e ("kallsyms: >>> Add self-test facility") in linus/master. >>> >>> I gave this a try on m68k (atari_defconfig + CONFIG_KALLSYMS_SELFTEST=y), >>> but it failed: >>> >>> start >>> kallsyms_lookup_name() for kallsyms_test_func_static failed: >>> addr=0, expect 60ab0 >>> kallsyms_lookup_name() for kallsyms_test_func failed: addr=0, expect 60ac0 >>> kallsyms_lookup_name() for kallsyms_test_func_weak failed: addr=0, >>> expect 60ac2 >>> kallsyms_lookup_name() for vmalloc failed: addr=0, expect c272a >>> kallsyms_lookup_name() for vfree failed: addr=0, expect c2142 >>> kallsyms_on_each_match_symbol() for kallsyms_test_func_static >>> failed: count=0, addr=0, expect 60ab0 >>> kallsyms_on_each_match_symbol() for kallsyms_test_func failed: >>> count=0, addr=0, expect 60ac0 >>> kallsyms_on_each_match_symbol() for kallsyms_test_func_weak >>> failed: count=0, addr=0, expect 60ac2 >>> kallsyms_on_each_match_symbol() for vmalloc failed: count=0, >>> addr=0, expect c272a >>> kallsyms_on_each_match_symbol() for vfree failed: count=0, addr=0, >>> expect c2142 >>> abort >>> >>> Given all addresses are zero, it looks like some required functionality >>> or config option is missing. >>> >>> $ grep SYM .config >>> CONFIG_KALLSYMS=y >>> CONFIG_KALLSYMS_SELFTEST=y >>> CONFIG_KALLSYMS_BASE_RELATIVE=y >>> # CONFIG_ASYMMETRIC_KEY_TYPE is not set >>> CONFIG_SYMBOLIC_ERRNAME=y >>> # CONFIG_STRIP_ASM_SYMS is not set >>> CONFIG_KALLSYMS_SELFTEST >>> >>> Do you have a clue? >> >> cat /proc/kallsyms | grep kallsyms_test_func >> Let's see if the compiler-generated symbols have some special suffixes. > > Thanks, looks normal to me: > > atari:~# cat /proc/kallsyms | grep kallsyms_test_func > 00060ab0 t kallsyms_test_func_static > 00060ac0 T kallsyms_test_func > 00060ac2 W kallsyms_test_func_weak > atari:~# It's incredible. I don't have a m68k environment and I'm trying to build a qemu environment. If you're in a hurry and willing, you can apply the debugging patch in the attachment. I'd like to see what's wrong. Use "dmesg | grep tst" to collect the output information. > > Gr{oetje,eeting}s, > > Geert > > -- > Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org > > In personal conversations with technical people, I call myself a hacker. 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