On Sun, Nov 17, 2024 at 2:59 PM Sergio González Collado <sergio.collado@xxxxxxxxx> wrote: > > The longest length of a symbol (KSYM_NAME_LEN) was increased to 512 > in the reference [1]. This patch adds kunit test suite to check the longest > symbol length. These tests verify that the longest symbol length defined > is supported. > > This test can also help other efforts for longer symbol length, > like [2]. > > The test suite defines two symbols, one with the longest length defined, > and other one whit the longest length defined +1. In the test suite > there are four tests, three positive and one negative. > > The first and third tests, verify that functions with names of the created > symbols, can be called or not. > > The second and fourth tests, verify that the symbols are created (or > not) in the kernel symbol table. > > [1] https://lore.kernel.org/lkml/20220802015052.10452-6-ojeda@xxxxxxxxxx/ > [2] https://lore.kernel.org/lkml/20240605032120.3179157-1-song@xxxxxxxxxx/ > > Tested-by: Martin Rodriguez Reboredo <yakoyoku@xxxxxxxxx> > Reviewed-by: Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx> > Signed-off-by: Sergio González Collado <sergio.collado@xxxxxxxxx> > Link: https://github.com/Rust-for-Linux/linux/issues/504 Hello! This patch is passing tests when it is built-in but it is failing when I run it as a module. Here is the result when run as a module with "modprobe longest_symbol_kunit": [ 30.446570] KTAP version 1 [ 30.446826] 1..1 [ 30.453560] KTAP version 1 [ 30.453785] # Subtest: longest-symbol [ 30.454376] # module: longest_symbol_kunit [ 30.457622] 1..4 [ 30.463765] ok 1 test_longest_symbol [ 30.471805] # test_longest_symbol_kallsyms: test_longest_symbol kallsyms: kprobe registered [ 30.478995] ok 2 test_longest_symbol_kallsyms [ 30.479735] ok 3 test_longest_symbol_plus1 [ 30.596269] # test_longest_symbol_plus1_kallsyms: test_longest_symbol_plus1 kallsyms: kprobe registered [ 30.602564] # test_longest_symbol_plus1_kallsyms: EXPECTATION FAILED at lib/longest_symbol_kunit.c:106 [ 30.602564] Expected longest_sym_plus1 == ((void *)0), but [ 30.602564] longest_sym_plus1 == ffffffffc01313e0 [ 30.602564] ((void *)0) == 0000000000000000 [ 30.603924] not ok 4 test_longest_symbol_plus1_kallsyms [ 30.606305] # longest-symbol: pass:3 fail:1 skip:0 total:4 [ 30.606669] # Totals: pass:3 fail:1 skip:0 total:4 [ 30.608618] not ok 1 longest-symbol Seems the symbol name is found when run as modules? Thanks! -Rae > --- > V1 -> V2: corrected CI tests. Added fix proposed at [3] > > [3] https://lore.kernel.org/lkml/Y9ES4UKl%2F+DtvAVS@xxxxxxxxx/T/#m3ef0e12bb834d01ed1ebdcae12ef5f2add342077 > --- > V2 -> V3: updated base and added MODULE_DESCRIPTION() and MODULE_AUTHOR() > --- > V3 -> V4: add x86 mantainers, add new reference. > --- > V4 -> V5: fixed typo, added improved description > > The test execution shoud result in something like: > > ``` > [20:04:35] =============== longest-symbol (4 subtests) ================ > [20:04:35] [PASSED] test_longest_symbol > [20:04:35] [PASSED] test_longest_symbol_kallsyms > [20:04:35] [PASSED] test_longest_symbol_plus1 > [20:04:35] [PASSED] test_longest_symbol_plus1_kallsyms > [20:04:35] ================= [PASSED] longest-symbol ================== > [20:04:35] ============================================================ > [20:04:35] Testing complete. Ran 4 tests: passed: 4 > ``` > > But also there are two warnings like: > > ``` > Symbol snnnng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nnng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nnnng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nnng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nnnnng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nnng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nnnng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nnng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nng1h2i3j4k5l6m7ng1h2i3j4k5l6m7ne too long for kallsyms (512 >= 512). > Please increase KSYM_NAME_LEN both in kernel and kallsyms.c > ``` > > Because the tests try to generate simbols of the same length as > KSYM_NAME_LEN. This is the expected outcome, as defined: > https://lore.kernel.org/all/20131023130753.GO29695@xxxxxxxxxxxxxxxxxx/ > > --- > arch/x86/tools/insn_decoder_test.c | 3 +- > lib/Kconfig.debug | 9 +++ > lib/Makefile | 2 + > lib/longest_symbol_kunit.c | 125 +++++++++++++++++++++++++++++ > 4 files changed, 138 insertions(+), 1 deletion(-) > create mode 100644 lib/longest_symbol_kunit.c > > diff --git a/arch/x86/tools/insn_decoder_test.c b/arch/x86/tools/insn_decoder_test.c > index 472540aeabc2..3bde35ea4188 100644 > --- a/arch/x86/tools/insn_decoder_test.c > +++ b/arch/x86/tools/insn_decoder_test.c > @@ -10,6 +10,7 @@ > #include <assert.h> > #include <unistd.h> > #include <stdarg.h> > +#include <linux/kallsysms.h> > > #define unlikely(cond) (cond) > > @@ -106,7 +107,7 @@ static void parse_args(int argc, char **argv) > } > } > > -#define BUFSIZE 256 > +#define BUFSIZE (256 + KSYM_NAME_LEN) > > int main(int argc, char **argv) > { > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug > index 7312ae7c3cc5..1f3059176637 100644 > --- a/lib/Kconfig.debug > +++ b/lib/Kconfig.debug > @@ -2820,6 +2820,15 @@ config FORTIFY_KUNIT_TEST > by the str*() and mem*() family of functions. For testing runtime > traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests. > > +config LONGEST_SYM_KUNIT_TEST > + tristate "Test the longest symbol possible" if !KUNIT_ALL_TESTS > + depends on KUNIT && KPROBES > + default KUNIT_ALL_TESTS > + help > + Tests the longest symbol possible > + > + If unsure, say N. > + > config HW_BREAKPOINT_KUNIT_TEST > bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS > depends on HAVE_HW_BREAKPOINT > diff --git a/lib/Makefile b/lib/Makefile > index 773adf88af41..fc878e716825 100644 > --- a/lib/Makefile > +++ b/lib/Makefile > @@ -389,6 +389,8 @@ CFLAGS_fortify_kunit.o += $(DISABLE_STRUCTLEAK_PLUGIN) > obj-$(CONFIG_FORTIFY_KUNIT_TEST) += fortify_kunit.o > obj-$(CONFIG_SIPHASH_KUNIT_TEST) += siphash_kunit.o > obj-$(CONFIG_USERCOPY_KUNIT_TEST) += usercopy_kunit.o > +obj-$(CONFIG_LONGEST_SYM_KUNIT_TEST) += longest_symbol_kunit.o > +CFLAGS_longest_symbol_kunit.o += $(call cc-disable-warning, missing-prototypes) > > obj-$(CONFIG_GENERIC_LIB_DEVMEM_IS_ALLOWED) += devmem_is_allowed.o > > diff --git a/lib/longest_symbol_kunit.c b/lib/longest_symbol_kunit.c > new file mode 100644 > index 000000000000..ebd26eedbf7b > --- /dev/null > +++ b/lib/longest_symbol_kunit.c > @@ -0,0 +1,125 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Test the longest symbol length. Execute with: > + * ./tools/testing/kunit/kunit.py run longest-symbol > + * --arch=x86_64 --kconfig_add CONFIG_KPROBES=y --kconfig_add CONFIG_MODULES=y > + * --kconfig_add CONFIG_RETPOLINE=n --kconfig_add CONFIG_CFI_CLANG=n > + * --kconfig_add CONFIG_MITIGATION_RETPOLINE=n > + */ > + > +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt > + > +#include <kunit/test.h> > +#include <linux/stringify.h> > +#include <linux/kprobes.h> > +#include <linux/kallsyms.h> > + > +#define DI(name) s##name##name > +#define DDI(name) DI(n##name##name) > +#define DDDI(name) DDI(n##name##name) > +#define DDDDI(name) DDDI(n##name##name) > +#define DDDDDI(name) DDDDI(n##name##name) > + > +#define PLUS1(name) __PASTE(name, e) > + > +/*Generate a symbol whose name length is 511 */ > +#define LONGEST_SYM_NAME DDDDDI(g1h2i3j4k5l6m7n) > + > +/*Generate a symbol whose name length is 512 */ > +#define LONGEST_SYM_NAME_PLUS1 PLUS1(LONGEST_SYM_NAME) > + > +#define RETURN_LONGEST_SYM 0xAAAAA > +#define RETURN_LONGEST_SYM_PLUS1 0x55555 > + > +noinline int LONGEST_SYM_NAME(void); > +noinline int LONGEST_SYM_NAME(void) > +{ > + return RETURN_LONGEST_SYM; > +} > + > +noinline int LONGEST_SYM_NAME_PLUS1(void); > +noinline int LONGEST_SYM_NAME_PLUS1(void) > +{ > + return RETURN_LONGEST_SYM_PLUS1; > +} > + > +_Static_assert(sizeof(__stringify(LONGEST_SYM_NAME)) == KSYM_NAME_LEN, > +"Incorrect symbol length found. Expected KSYM_NAME_LEN: " > +__stringify(KSYM_NAME) ", but found: " > +__stringify(sizeof(LONGEST_SYM_NAME))); > + > +static void test_longest_symbol(struct kunit *test) > +{ > + KUNIT_EXPECT_EQ(test, RETURN_LONGEST_SYM, LONGEST_SYM_NAME()); > +}; > + > +static void test_longest_symbol_kallsyms(struct kunit *test) > +{ > + unsigned long (*kallsyms_lookup_name)(const char *name); > + static int (*longest_sym)(void); > + > + struct kprobe kp = { > + .symbol_name = "kallsyms_lookup_name", > + }; > + > + if (register_kprobe(&kp) < 0) { > + pr_info("%s: kprobe not registered\n", __func__); > + KUNIT_FAIL(test, "test_longest_symbol kallsysms: kprobe not registered\n"); > + return; > + } > + > + kunit_warn(test, "test_longest_symbol kallsyms: kprobe registered\n"); > + kallsyms_lookup_name = (unsigned long (*)(const char *name))kp.addr; > + unregister_kprobe(&kp); > + > + longest_sym = > + (void *) kallsyms_lookup_name(__stringify(LONGEST_SYM_NAME)); > + KUNIT_EXPECT_EQ(test, RETURN_LONGEST_SYM, longest_sym()); > +}; > + > +static void test_longest_symbol_plus1(struct kunit *test) > +{ > + KUNIT_EXPECT_EQ(test, RETURN_LONGEST_SYM_PLUS1, LONGEST_SYM_NAME_PLUS1()); > +}; > + > +static void test_longest_symbol_plus1_kallsyms(struct kunit *test) > +{ > + unsigned long (*kallsyms_lookup_name)(const char *name); > + static int (*longest_sym_plus1)(void); > + > + struct kprobe kp = { > + .symbol_name = "kallsyms_lookup_name", > + }; > + > + if (register_kprobe(&kp) < 0) { > + pr_info("%s: kprobe not registered\n", __func__); > + KUNIT_FAIL(test, "test_longest_symbol kallsysms: kprobe not registered\n"); > + return; > + } > + > + kunit_warn(test, "test_longest_symbol_plus1 kallsyms: kprobe registered\n"); > + kallsyms_lookup_name = (unsigned long (*)(const char *name))kp.addr; > + unregister_kprobe(&kp); > + > + longest_sym_plus1 = > + (void *) kallsyms_lookup_name(__stringify(LONGEST_SYM_NAME_PLUS1)); > + KUNIT_EXPECT_NULL(test, longest_sym_plus1); > +}; > + > +static struct kunit_case longest_symbol_test_cases[] = { > + KUNIT_CASE(test_longest_symbol), > + KUNIT_CASE(test_longest_symbol_kallsyms), > + KUNIT_CASE(test_longest_symbol_plus1), > + KUNIT_CASE(test_longest_symbol_plus1_kallsyms), > + {} > +}; > + > +static struct kunit_suite longest_symbol_test_suite = { > + .name = "longest-symbol", > + .test_cases = longest_symbol_test_cases, > +}; > +kunit_test_suite(longest_symbol_test_suite); > + > +MODULE_LICENSE("GPL"); > +MODULE_DESCRIPTION("Test the longest symbol length"); > +MODULE_AUTHOR("Sergio González Collado"); > -- > 2.39.2 > > -- > You received this message because you are subscribed to the Google Groups "KUnit Development" group. > To unsubscribe from this group and stop receiving emails from it, send an email to kunit-dev+unsubscribe@xxxxxxxxxxxxxxxx. > To view this discussion visit https://groups.google.com/d/msgid/kunit-dev/20241117195923.222145-1-sergio.collado%40gmail.com.
