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[209.85.128.172]) by smtp.gmail.com with ESMTPSA id x8-20020ac84d48000000b00398a7c860c2sm3547853qtv.4.2022.12.15.06.43.12 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 15 Dec 2022 06:43:12 -0800 (PST) Received: by mail-yw1-f172.google.com with SMTP id 00721157ae682-3e78d07ab4fso43670827b3.9; Thu, 15 Dec 2022 06:43:12 -0800 (PST) X-Received: by 2002:a0d:dd4b:0:b0:370:61f5:b19e with SMTP id g72-20020a0ddd4b000000b0037061f5b19emr28138210ywe.316.1671115391829; Thu, 15 Dec 2022 06:43:11 -0800 (PST) MIME-Version: 1.0 References: <20221115083349.1662-1-thunder.leizhen@huawei.com> <49070ac3-02bb-a3b3-b929-ede07e3b2c95@huawei.com> In-Reply-To: <49070ac3-02bb-a3b3-b929-ede07e3b2c95@huawei.com> From: Geert Uytterhoeven Date: Thu, 15 Dec 2022 15:43:00 +0100 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v9] kallsyms: Add self-test facility To: "Leizhen (ThunderTown)" Cc: Josh Poimboeuf , Jiri Kosina , Miroslav Benes , Petr Mladek , Joe Lawrence , live-patching@vger.kernel.org, linux-kernel@vger.kernel.org, Masahiro Yamada , Alexei Starovoitov , Jiri Olsa , Kees Cook , Andrew Morton , Luis Chamberlain , linux-modules@vger.kernel.org, Steven Rostedt , Ingo Molnar , David Laight , linux-m68k , "Jason A. Donenfeld" Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: Hi Zhen, On Thu, Dec 15, 2022 at 2:58 PM Leizhen (ThunderTown) wrote: > On 2022/12/15 21:24, Geert Uytterhoeven wrote: > > 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 > 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. On 30f3bb09778de64 it fails the same way: start kallsyms_lookup_name() for kallsyms_test_func_static failed: addr=8dbc, expect 60308 kallsyms_lookup_name() for kallsyms_test_func failed: addr=8dbc, expect 60318 kallsyms_lookup_name() for kallsyms_test_func_weak failed: addr=8dbc, expect 6031a kallsyms_lookup_name() for vmalloc failed: addr=8dbc, expect bdc88 kallsyms_lookup_name() for vfree failed: addr=8dbc, expect bd6de kallsyms_on_each_match_symbol() for kallsyms_test_func_static failed: count=24890, addr=1ee870, expect 60308 kallsyms_on_each_match_symbol() for kallsyms_test_func failed: count=24890, addr=1ee870, expect 60318 kallsyms_on_each_match_symbol() for kallsyms_test_func_weak failed: count=24890, addr=1ee870, expect 6031a kallsyms_on_each_match_symbol() for vmalloc failed: count=24890, addr=1ee870, expect bdc88 kallsyms_on_each_match_symbol() for vfree failed: count=24890, addr=1ee870, expect bd6de abort > Is m68k big-endian? Yes it is. And 32-bit values are aligned to only 2 bytes. 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. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds