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[209.85.219.179]) by smtp.gmail.com with ESMTPSA id i10-20020a05620a404a00b006e54251993esm11865181qko.97.2022.12.15.01.39.50 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 15 Dec 2022 01:39:50 -0800 (PST) Received: by mail-yb1-f179.google.com with SMTP id b16so2901017yba.0; Thu, 15 Dec 2022 01:39:50 -0800 (PST) X-Received: by 2002:a25:d655:0:b0:6fc:1c96:c9fe with SMTP id n82-20020a25d655000000b006fc1c96c9femr34405249ybg.36.1671097190502; Thu, 15 Dec 2022 01:39:50 -0800 (PST) MIME-Version: 1.0 References: <20221115083349.1662-1-thunder.leizhen@huawei.com> In-Reply-To: From: Geert Uytterhoeven Date: Thu, 15 Dec 2022 10:39:39 +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 Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: 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:~# 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