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 031C0C4332F for ; Thu, 15 Dec 2022 14:40:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229658AbiLOOku (ORCPT ); Thu, 15 Dec 2022 09:40:50 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53562 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229635AbiLOOks (ORCPT ); Thu, 15 Dec 2022 09:40:48 -0500 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BBBF05F71; Thu, 15 Dec 2022 06:40:44 -0800 (PST) Received: from dggpemm500006.china.huawei.com (unknown [172.30.72.54]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4NXvtZ5D7mzqSnt; Thu, 15 Dec 2022 22:36:22 +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 22:40:39 +0800 Subject: Re: [PATCH v9] kallsyms: Add self-test facility From: "Leizhen (ThunderTown)" 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 , "Jason A. Donenfeld" References: <20221115083349.1662-1-thunder.leizhen@huawei.com> <49070ac3-02bb-a3b3-b929-ede07e3b2c95@huawei.com> Message-ID: Date: Thu, 15 Dec 2022 22:40:28 +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: <49070ac3-02bb-a3b3-b929-ede07e3b2c95@huawei.com> Content-Type: multipart/mixed; boundary="------------02EB81ACC5D49A141807CD0A" Content-Language: en-US X-Originating-IP: [10.174.178.55] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To dggpemm500006.china.huawei.com (7.185.36.236) X-CFilter-Loop: Reflected Precedence: bulk List-ID: --------------02EB81ACC5D49A141807CD0A Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit On 2022/12/15 21:58, Leizhen (ThunderTown) wrote: > > > On 2022/12/15 21:24, Geert Uytterhoeven wrote: >> Hi Zhen, >> >> CC Jason >> >> On Thu, Dec 15, 2022 at 1:34 PM Leizhen (ThunderTown) >> wrote: >>> On 2022/12/15 17:39, Geert Uytterhoeven wrote: >>>> 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. >> >> Still fails: >> >> tst: found kallsyms_test_func at index=12845 >> tst: [12533] = kallsyms_test_func, seq=17370, offset=191223 >> tst: [18800] = kallsyms_test_func, seq=23193, offset=259263 >> tst: [21934] = kallsyms_test_func, seq=2527, offset=22331 >> tst: [23501] = kallsyms_test_func, seq=11792, offset=126366 >> tst: [24284] = kallsyms_test_func, seq=8427, offset=87395 >> tst: [24676] = kallsyms_test_func, seq=21896, offset=243536 >> tst: [24872] = kallsyms_test_func, seq=22571, offset=251856 >> tst: [24970] = kallsyms_test_func, seq=23264, offset=260074 >> tst: [25019] = kallsyms_test_func, seq=9003, offset=93752 >> tst: [25043] = kallsyms_test_func, seq=14324, offset=155117 >> tst: [25055] = kallsyms_test_func, seq=5942, offset=62266 >> tst: [25061] = kallsyms_test_func, seq=14347, offset=155467 >> tst: [25064] = kallsyms_test_func, seq=14350, offset=155512 >> tst: [25066] = kallsyms_test_func, seq=14346, offset=155457 >> tst: [25067] = kallsyms_test_func, seq=14354, offset=155565 > > - pr_warn("tst: [%d] = %s, seq=%d, offset=%d\n", mid, name, seq, off); > + pr_warn("tst: [%d] = %s, seq=%d, offset=%d\n", mid, namebuf, seq, off); > > Sorry, a variable in the debugging code is incorrectly written. 'name' should > be replaced with 'namebuf', then we can see which function the comparison is wrong. I attached debug patch v2. > >> >> However, the binary search sequence looks very suspicious. >> After investigation, it turns out compare_symbol_name() and strcmp() >> always return positive numbers. >> >> Looks like commit 3bc753c06dd02a35 ("kbuild: treat char as always >> unsigned") is to blame. > > Oh, maybe you can "git reset --hard 30f3bb09778de64" and try again. > 30f3bb09778de64 kallsyms: Add self-test facility > > But the latest kernel is OK on x86. So other patches are unlikely to > affect this function. > > Is m68k big-endian? > >> >> Changing: >> >> --- a/arch/m68k/include/asm/string.h >> +++ b/arch/m68k/include/asm/string.h >> @@ -42,7 +42,7 @@ static inline char *strncpy(char *dest, const >> char *src, size_t n) >> #define __HAVE_ARCH_STRCMP >> static inline int strcmp(const char *cs, const char *ct) >> { >> - char res; >> + signed char res; >> >> asm ("\n" >> "1: move.b (%0)+,%2\n" /* get *cs */ >> >> fixes strcmp, but the test still fails: >> >> tst: kallsyms_lookup_names() is OK, name=kallsyms_test_func, i=0 > > i=0, i is impossible zero. Maybe kallsyms_lookup_names() always return success now. > >> kallsyms_selftest: kallsyms_lookup_name() for >> kallsyms_test_func_static failed: addr=8e1c, expect 60cd4 >> kallsyms_selftest: kallsyms_lookup_name() for kallsyms_test_func >> failed: addr=8e1c, expect 60ce4 >> kallsyms_selftest: kallsyms_lookup_name() for >> kallsyms_test_func_weak failed: addr=8e1c, expect 60ce6 >> kallsyms_selftest: kallsyms_lookup_name() for vmalloc failed: >> addr=8e1c, expect c2946 >> kallsyms_selftest: kallsyms_lookup_name() for vfree failed: >> addr=8e1c, expect c235e >> kallsyms_selftest: kallsyms_on_each_match_symbol() for >> kallsyms_test_func_static failed: count=25068, addr=1f3d3c, expect >> 60cd4 >> kallsyms_selftest: kallsyms_on_each_match_symbol() for >> kallsyms_test_func failed: count=25068, addr=1f3d3c, expect 60ce4 >> kallsyms_selftest: kallsyms_on_each_match_symbol() for >> kallsyms_test_func_weak failed: count=25068, addr=1f3d3c, expect 60ce6 >> kallsyms_selftest: kallsyms_on_each_match_symbol() for vmalloc >> failed: count=25068, addr=1f3d3c, expect c2946 >> kallsyms_selftest: kallsyms_on_each_match_symbol() for vfree >> failed: count=25068, addr=1f3d3c, expect c235e >> kallsyms_selftest: abort >> >> Dropping -funsigned-char doesn't improve upon that... >> >> 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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