[PATCH v6] Kunit to check the longest symbol length
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Sergio González Collado
Jan 26, 2025, 5:36:48 PM1/26/25
to David Gow, Rae Moar, linux-k...@vger.kernel.org, kuni...@googlegroups.com, Miguel Ojeda, Alex Gaynor, Boqun Feng, Gary Guo, Björn Roy Baron, Benno Lossin, Andreas Hindborg, Alice Ryhl, David Rheinsberg, rust-fo...@vger.kernel.org, x...@kernel.org, Sergio González Collado, Martin Rodriguez Reboredo, Shuah Khan
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 one symbol with the longest possible length.
The first test verify that functions with names of the created
symbol, can be called or not.
The second test, verify that the symbols are created (or
not) in the kernel symbol table.
[1] https://lore.kernel.org/lkml/20220802015052...@kernel.org/
[2] https://lore.kernel.org/lkml/20240605032120...@kernel.org/
Tested-by: Martin Rodriguez Reboredo <yako...@gmail.com>
Reviewed-by: Shuah Khan <sk...@linuxfoundation.org>
Signed-off-by: Sergio González Collado <sergio....@gmail.com>
Link: https://github.com/Rust-for-Linux/linux/issues/504
---
V5 -> V6: remove tests with symbols of length KSYM_NAME_LEN+1
---
V4 -> V5: fixed typo, added improved description
---
V3 -> V4: add x86 mantainers, add new reference.
---
V2 -> V3: updated base and added MODULE_DESCRIPTION() and MODULE_AUTHOR()
---
V1 -> V2: corrected CI tests. Added fix proposed at [3]
[3] https://lore.kernel.org/lkml/Y9ES4UKl%2F+D...@gmail.com/T/#m3ef0e12bb834d01ed1ebdcae12ef5f2add342077
The test execution should 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] longest-symbol ==================
[20:04:35] ============================================================
[20:04:35] Testing complete. Ran 4 tests: passed: 4
```
---
arch/x86/tools/insn_decoder_test.c | 3 +-
lib/Kconfig.debug | 9 ++++
lib/Makefile | 2 +
lib/longest_symbol_kunit.c | 84 ++++++++++++++++++++++++++++++
4 files changed, 97 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 5f1874622175..4c3a61862281 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -2828,6 +2828,15 @@ 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 d5cfc7afbbb8..e8fec9defec2 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -393,6 +393,8 @@ obj-$(CONFIG_FORTIFY_KUNIT_TEST) += fortify_kunit.o
obj-$(CONFIG_CRC_KUNIT_TEST) += crc_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..38ae117647e4
--- /dev/null
+++ b/lib/longest_symbol_kunit.c
@@ -0,0 +1,84 @@
+// 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)
+
+#define RETURN_LONGEST_SYM 0xAAAAA
+
+noinline int LONGEST_SYM_NAME(void);
+noinline int LONGEST_SYM_NAME(void)
+{
+ return RETURN_LONGEST_SYM;
+}
+
+_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 struct kunit_case longest_symbol_test_cases[] = {
+ KUNIT_CASE(test_longest_symbol),
+ KUNIT_CASE(test_longest_symbol_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
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 one symbol with the longest possible length.
The first test verify that functions with names of the created
symbol, can be called or not.
The second test, verify that the symbols are created (or
not) in the kernel symbol table.
[1] https://lore.kernel.org/lkml/20220802015052...@kernel.org/
[2] https://lore.kernel.org/lkml/20240605032120...@kernel.org/
Tested-by: Martin Rodriguez Reboredo <yako...@gmail.com>
Reviewed-by: Shuah Khan <sk...@linuxfoundation.org>
Signed-off-by: Sergio González Collado <sergio....@gmail.com>
Link: https://github.com/Rust-for-Linux/linux/issues/504
---
V5 -> V6: remove tests with symbols of length KSYM_NAME_LEN+1
---
V4 -> V5: fixed typo, added improved description
---
V3 -> V4: add x86 mantainers, add new reference.
---
V2 -> V3: updated base and added MODULE_DESCRIPTION() and MODULE_AUTHOR()
---
V1 -> V2: corrected CI tests. Added fix proposed at [3]
[3] https://lore.kernel.org/lkml/Y9ES4UKl%2F+D...@gmail.com/T/#m3ef0e12bb834d01ed1ebdcae12ef5f2add342077
The test execution should 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] longest-symbol ==================
[20:04:35] ============================================================
[20:04:35] Testing complete. Ran 4 tests: passed: 4
```
---
arch/x86/tools/insn_decoder_test.c | 3 +-
lib/Kconfig.debug | 9 ++++
lib/Makefile | 2 +
lib/longest_symbol_kunit.c | 84 ++++++++++++++++++++++++++++++
4 files changed, 97 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 5f1874622175..4c3a61862281 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -2828,6 +2828,15 @@ 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 d5cfc7afbbb8..e8fec9defec2 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -393,6 +393,8 @@ obj-$(CONFIG_FORTIFY_KUNIT_TEST) += fortify_kunit.o
obj-$(CONFIG_CRC_KUNIT_TEST) += crc_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..38ae117647e4
--- /dev/null
+++ b/lib/longest_symbol_kunit.c
@@ -0,0 +1,84 @@
+// 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)
+
+#define RETURN_LONGEST_SYM 0xAAAAA
+
+noinline int LONGEST_SYM_NAME(void);
+noinline int LONGEST_SYM_NAME(void)
+{
+ return RETURN_LONGEST_SYM;
+}
+
+_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 struct kunit_case longest_symbol_test_cases[] = {
+ KUNIT_CASE(test_longest_symbol),
+ KUNIT_CASE(test_longest_symbol_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
Rae Moar
Jan 27, 2025, 4:04:17 PM1/27/25
to Sergio González Collado, David Gow, linux-k...@vger.kernel.org, kuni...@googlegroups.com, Miguel Ojeda, Alex Gaynor, Boqun Feng, Gary Guo, Björn Roy Baron, Benno Lossin, Andreas Hindborg, Alice Ryhl, David Rheinsberg, rust-fo...@vger.kernel.org, x...@kernel.org, Martin Rodriguez Reboredo, Shuah Khan
On Sun, Jan 26, 2025 at 5:36 PM Sergio González Collado
<sergio....@gmail.com> 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 one symbol with the longest possible length.
>
> The first test verify that functions with names of the created
> symbol, can be called or not.
>
> The second test, verify that the symbols are created (or
> not) in the kernel symbol table.
>
> [1] https://lore.kernel.org/lkml/20220802015052...@kernel.org/
> [2] https://lore.kernel.org/lkml/20240605032120...@kernel.org/
>
> Tested-by: Martin Rodriguez Reboredo <yako...@gmail.com>
> Reviewed-by: Shuah Khan <sk...@linuxfoundation.org>
> Signed-off-by: Sergio González Collado <sergio....@gmail.com>
> Link: https://github.com/Rust-for-Linux/linux/issues/504
Hi Sergio!
<sergio....@gmail.com> 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 one symbol with the longest possible length.
>
> The first test verify that functions with names of the created
> symbol, can be called or not.
>
> The second test, verify that the symbols are created (or
> not) in the kernel symbol table.
>
> [1] https://lore.kernel.org/lkml/20220802015052...@kernel.org/
> [2] https://lore.kernel.org/lkml/20240605032120...@kernel.org/
>
> Tested-by: Martin Rodriguez Reboredo <yako...@gmail.com>
> Reviewed-by: Shuah Khan <sk...@linuxfoundation.org>
> Signed-off-by: Sergio González Collado <sergio....@gmail.com>
> Link: https://github.com/Rust-for-Linux/linux/issues/504
Thanks for sending another version of this test. This now looks good
to me! The test passes both built-in to the kernel and loaded as a
module.
Happy to take this patch though the kselftest/kunit branch. However
this patch does not cleanly apply to that branch right now. There are
just a few lines in lib/Makefile that differ. It would be an easy fix
of rebasing the patch and sending out a new version. Or would you
prefer sending it through another branch? Let me know.
But other than the need to rebase, this patch looks good to me:
Reviewed-by: Rae Moar <rm...@google.com>
Thanks!
-Rae
Miguel Ojeda
Jan 28, 2025, 1:50:54 AM1/28/25
to Sergio González Collado, David Gow, Rae Moar, linux-k...@vger.kernel.org, kuni...@googlegroups.com, Miguel Ojeda, Alex Gaynor, Boqun Feng, Gary Guo, Björn Roy Baron, Benno Lossin, Andreas Hindborg, Alice Ryhl, David Rheinsberg, rust-fo...@vger.kernel.org, x...@kernel.org, Martin Rodriguez Reboredo, Shuah Khan
On Sun, Jan 26, 2025 at 11:36 PM Sergio González Collado
<sergio....@gmail.com> wrote:
>
> +#include <linux/kallsysms.h>
Typo?
Cheers,
Miguel
<sergio....@gmail.com> wrote:
>
> +#include <linux/kallsysms.h>
Typo?
Cheers,
Miguel
Sergio González Collado
Jan 28, 2025, 2:04:39 AM1/28/25
to David Gow, Rae Moar, linux-k...@vger.kernel.org, kuni...@googlegroups.com, Miguel Ojeda, Alex Gaynor, Boqun Feng, Gary Guo, Björn Roy Baron, Benno Lossin, Andreas Hindborg, Alice Ryhl, David Rheinsberg, rust-fo...@vger.kernel.org, x...@kernel.org, Sergio González Collado, Martin Rodriguez Reboredo, Shuah Khan
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 one symbol with the longest possible length.
The first test verify that functions with names of the created
symbol, can be called or not.
The second test, verify that the symbols are created (or
not) in the kernel symbol table.
[1] https://lore.kernel.org/lkml/20220802015052...@kernel.org/
[2] https://lore.kernel.org/lkml/20240605032120...@kernel.org/
Tested-by: Martin Rodriguez Reboredo <yako...@gmail.com>
Reviewed-by: Shuah Khan <sk...@linuxfoundation.org>
Reviewed-by: Rae Moar <rm...@google.com>
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 one symbol with the longest possible length.
The first test verify that functions with names of the created
symbol, can be called or not.
The second test, verify that the symbols are created (or
not) in the kernel symbol table.
[1] https://lore.kernel.org/lkml/20220802015052...@kernel.org/
[2] https://lore.kernel.org/lkml/20240605032120...@kernel.org/
Tested-by: Martin Rodriguez Reboredo <yako...@gmail.com>
Reviewed-by: Shuah Khan <sk...@linuxfoundation.org>
Signed-off-by: Sergio González Collado <sergio....@gmail.com>
Link: https://github.com/Rust-for-Linux/linux/issues/504
---
Link: https://github.com/Rust-for-Linux/linux/issues/504
V6 -> V7: rebased
---
V5 -> V6: remove tests with symbols of length KSYM_NAME_LEN+1
---
V4 -> V5: fixed typo, added improved description
---
V3 -> V4: add x86 mantainers, add new reference.
---
V2 -> V3: updated base and added MODULE_DESCRIPTION() and MODULE_AUTHOR()
---
V1 -> V2: corrected CI tests. Added fix proposed at [3]
[3] https://lore.kernel.org/lkml/Y9ES4UKl%2F+D...@gmail.com/T/#m3ef0e12bb834d01ed1ebdcae12ef5f2add342077
The test execution should result in something like:
```
V5 -> V6: remove tests with symbols of length KSYM_NAME_LEN+1
---
V4 -> V5: fixed typo, added improved description
---
V3 -> V4: add x86 mantainers, add new reference.
---
V2 -> V3: updated base and added MODULE_DESCRIPTION() and MODULE_AUTHOR()
---
V1 -> V2: corrected CI tests. Added fix proposed at [3]
[3] https://lore.kernel.org/lkml/Y9ES4UKl%2F+D...@gmail.com/T/#m3ef0e12bb834d01ed1ebdcae12ef5f2add342077
The test execution should result in something like:
```
---
arch/x86/tools/insn_decoder_test.c | 3 +-
lib/Kconfig.debug | 9 ++++
lib/Makefile | 2 +
lib/longest_symbol_kunit.c | 84 ++++++++++++++++++++++++++++++
4 files changed, 97 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 775966cf6114..9bab160efa4a 100644
arch/x86/tools/insn_decoder_test.c | 3 +-
lib/Kconfig.debug | 9 ++++
lib/Makefile | 2 +
lib/longest_symbol_kunit.c | 84 ++++++++++++++++++++++++++++++
4 files changed, 97 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
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -2852,6 +2852,15 @@ 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 f1c6e9d76a7c..33b5ef908764 100644
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
--
2.39.2
Sergio González Collado
Jan 28, 2025, 7:24:29 AM1/28/25
to Miguel Ojeda, David Gow, Rae Moar, linux-k...@vger.kernel.org, kuni...@googlegroups.com, Miguel Ojeda, Alex Gaynor, Boqun Feng, Gary Guo, Björn Roy Baron, Benno Lossin, Andreas Hindborg, Alice Ryhl, David Rheinsberg, rust-fo...@vger.kernel.org, x...@kernel.org, Martin Rodriguez Reboredo, Shuah Khan
Hello
> > +#include <linux/kallsysms.h>
>
> Typo?
#include <linux/kallsysms.h> is needed to be able to read
KSYM_NAME_LEN: https://elixir.bootlin.com/linux/v6.13/source/include/linux/kallsyms.h#L18
In the file insn_decoder_test.c, is added otherwise, when configuring
that test with CONFIG_X86_DECODER_SELFTEST, you would get the error
```
arch/x86/tools/insn_decoder_test.c:110:24: error: ‘KSYM_NAME_LEN’
undeclared (first use in this function)
110 | #define BUFSIZE (256 + KSYM_NAME_LEN)
```
This was proposed here:
https://lore.kernel.org/lkml/Y9ES4UKl%2F+D...@gmail.com/
Cheers,
Sergio
Sergio
> > +#include <linux/kallsysms.h>
>
> Typo?
#include <linux/kallsysms.h> is needed to be able to read
KSYM_NAME_LEN: https://elixir.bootlin.com/linux/v6.13/source/include/linux/kallsyms.h#L18
In the file insn_decoder_test.c, is added otherwise, when configuring
that test with CONFIG_X86_DECODER_SELFTEST, you would get the error
```
arch/x86/tools/insn_decoder_test.c:110:24: error: ‘KSYM_NAME_LEN’
undeclared (first use in this function)
110 | #define BUFSIZE (256 + KSYM_NAME_LEN)
```
This was proposed here:
https://lore.kernel.org/lkml/Y9ES4UKl%2F+D...@gmail.com/
Cheers,
Sergio
Sergio
Miguel Ojeda
Jan 28, 2025, 3:56:25 PM1/28/25
to Sergio González Collado, David Gow, Rae Moar, linux-k...@vger.kernel.org, kuni...@googlegroups.com, Miguel Ojeda, Alex Gaynor, Boqun Feng, Gary Guo, Björn Roy Baron, Benno Lossin, Andreas Hindborg, Alice Ryhl, David Rheinsberg, rust-fo...@vger.kernel.org, x...@kernel.org, Martin Rodriguez Reboredo, Shuah Khan
On Tue, Jan 28, 2025 at 1:24 PM Sergio González Collado
<sergio....@gmail.com> wrote:
>
> > > +#include <linux/kallsysms.h>
> >
> > Typo?
>
> #include <linux/kallsysms.h> is needed to be able to read
> KSYM_NAME_LEN: https://elixir.bootlin.com/linux/v6.13/source/include/linux/kallsyms.h#L18
What I meant is that the `#include` in the patch is:
<sergio....@gmail.com> wrote:
>
> > > +#include <linux/kallsysms.h>
> >
> > Typo?
>
> #include <linux/kallsysms.h> is needed to be able to read
> KSYM_NAME_LEN: https://elixir.bootlin.com/linux/v6.13/source/include/linux/kallsyms.h#L18
kallsysms.h
which is different from:
kallsyms.h
Does that file build? Or am I missing something?
I just tried, and I indeed get:
HOSTCC arch/x86/tools/insn_decoder_test
arch/x86/tools/insn_decoder_test.c:13:10: fatal error:
'linux/kallsysms.h' file not found
13 | #include <linux/kallsysms.h>
| ^~~~~~~~~~~~~~~~~~~
1 error generated.
Thanks!
Cheers,
Miguel
Rae Moar
Jan 28, 2025, 4:07:23 PM1/28/25
to Miguel Ojeda, Sergio González Collado, David Gow, linux-k...@vger.kernel.org, kuni...@googlegroups.com, Miguel Ojeda, Alex Gaynor, Boqun Feng, Gary Guo, Björn Roy Baron, Benno Lossin, Andreas Hindborg, Alice Ryhl, David Rheinsberg, rust-fo...@vger.kernel.org, x...@kernel.org, Martin Rodriguez Reboredo, Shuah Khan
Oh yep definitely missed that typo. Thanks for catching this!
Thanks!
-Rae
>
> --
> 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+...@googlegroups.com.
> To view this discussion visit https://groups.google.com/d/msgid/kunit-dev/CANiq72kXG4qURXjnZZTLPMn-k_WwFt0yabR0nfCAzDMqYNJKHg%40mail.gmail.com.
Sergio González Collado
Feb 2, 2025, 2:24:22 PM2/2/25
to David Gow, Rae Moar, linux-k...@vger.kernel.org, kuni...@googlegroups.com, Miguel Ojeda, Alex Gaynor, Boqun Feng, Gary Guo, Björn Roy Baron, Benno Lossin, Andreas Hindborg, Alice Ryhl, David Rheinsberg, rust-fo...@vger.kernel.org, x...@kernel.org, Sergio González Collado, Martin Rodriguez Reboredo, Shuah Khan
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 one symbol with the longest possible length.
The first test verify that functions with names of the created
symbol, can be called or not.
The second test, verify that the symbols are created (or
not) in the kernel symbol table.
[1] https://lore.kernel.org/lkml/20220802015052...@kernel.org/
[2] https://lore.kernel.org/lkml/20240605032120...@kernel.org/
Tested-by: Martin Rodriguez Reboredo <yako...@gmail.com>
Reviewed-by: Shuah Khan <sk...@linuxfoundation.org>
Reviewed-by: Rae Moar <rm...@google.com>
Signed-off-by: Sergio González Collado <sergio....@gmail.com>
Link: https://github.com/Rust-for-Linux/linux/issues/504
---
V7 -> V8: typo fixed & rebased
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 one symbol with the longest possible length.
The first test verify that functions with names of the created
symbol, can be called or not.
The second test, verify that the symbols are created (or
not) in the kernel symbol table.
[1] https://lore.kernel.org/lkml/20220802015052...@kernel.org/
[2] https://lore.kernel.org/lkml/20240605032120...@kernel.org/
Tested-by: Martin Rodriguez Reboredo <yako...@gmail.com>
Reviewed-by: Shuah Khan <sk...@linuxfoundation.org>
Reviewed-by: Rae Moar <rm...@google.com>
Signed-off-by: Sergio González Collado <sergio....@gmail.com>
Link: https://github.com/Rust-for-Linux/linux/issues/504
---
---
V6 -> V7: rebased
---
V5 -> V6: remove tests with symbols of length KSYM_NAME_LEN+1
---
V4 -> V5: fixed typo, added improved description
---
V3 -> V4: add x86 mantainers, add new reference.
---
V2 -> V3: updated base and added MODULE_DESCRIPTION() and MODULE_AUTHOR()
---
V1 -> V2: corrected CI tests. Added fix proposed at [3]
[3] https://lore.kernel.org/lkml/Y9ES4UKl%2F+D...@gmail.com/T/#m3ef0e12bb834d01ed1ebdcae12ef5f2add342077
The test execution should result in something like:
```
V6 -> V7: rebased
---
V5 -> V6: remove tests with symbols of length KSYM_NAME_LEN+1
---
V4 -> V5: fixed typo, added improved description
---
V3 -> V4: add x86 mantainers, add new reference.
---
V2 -> V3: updated base and added MODULE_DESCRIPTION() and MODULE_AUTHOR()
---
V1 -> V2: corrected CI tests. Added fix proposed at [3]
[3] https://lore.kernel.org/lkml/Y9ES4UKl%2F+D...@gmail.com/T/#m3ef0e12bb834d01ed1ebdcae12ef5f2add342077
The test execution should 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] longest-symbol ==================
[20:04:35] ============================================================
[20:04:35] Testing complete. Ran 4 tests: passed: 4
```
[20:04:35] [PASSED] test_longest_symbol
[20:04:35] [PASSED] test_longest_symbol_kallsyms
[20:04:35] ================= [PASSED] longest-symbol ==================
[20:04:35] ============================================================
[20:04:35] Testing complete. Ran 4 tests: passed: 4
```
---
arch/x86/tools/insn_decoder_test.c | 3 +-
lib/Kconfig.debug | 9 ++++
lib/Makefile | 2 +
lib/longest_symbol_kunit.c | 84 ++++++++++++++++++++++++++++++
4 files changed, 97 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..6c2986d2ad11 100644
arch/x86/tools/insn_decoder_test.c | 3 +-
lib/Kconfig.debug | 9 ++++
lib/Makefile | 2 +
lib/longest_symbol_kunit.c | 84 ++++++++++++++++++++++++++++++
4 files changed, 97 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
--- 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/kallsyms.h>
+++ b/arch/x86/tools/insn_decoder_test.c
@@ -10,6 +10,7 @@
#include <assert.h>
#include <unistd.h>
#include <stdarg.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
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -2838,6 +2838,15 @@ 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 d5cfc7afbbb8..e8fec9defec2 100644
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
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -393,6 +393,8 @@ obj-$(CONFIG_FORTIFY_KUNIT_TEST) += fortify_kunit.o
obj-$(CONFIG_CRC_KUNIT_TEST) += crc_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..2a2dd1151097
+++ b/lib/Makefile
@@ -393,6 +393,8 @@ obj-$(CONFIG_FORTIFY_KUNIT_TEST) += fortify_kunit.o
obj-$(CONFIG_CRC_KUNIT_TEST) += crc_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
--
2.39.2
Rae Moar
Feb 7, 2025, 4:54:01 PM2/7/25
to Sergio González Collado, David Gow, linux-k...@vger.kernel.org, kuni...@googlegroups.com, Miguel Ojeda, Alex Gaynor, Boqun Feng, Gary Guo, Björn Roy Baron, Benno Lossin, Andreas Hindborg, Alice Ryhl, David Rheinsberg, rust-fo...@vger.kernel.org, x...@kernel.org, Martin Rodriguez Reboredo, Shuah Khan
On Sun, Feb 2, 2025 at 2:24 PM Sergio González Collado
<sergio....@gmail.com> 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 one symbol with the longest possible length.
>
> The first test verify that functions with names of the created
> symbol, can be called or not.
>
> The second test, verify that the symbols are created (or
> not) in the kernel symbol table.
>
> [1] https://lore.kernel.org/lkml/20220802015052...@kernel.org/
> [2] https://lore.kernel.org/lkml/20240605032120...@kernel.org/
>
> Tested-by: Martin Rodriguez Reboredo <yako...@gmail.com>
> Reviewed-by: Shuah Khan <sk...@linuxfoundation.org>
> Reviewed-by: Rae Moar <rm...@google.com>
> Signed-off-by: Sergio González Collado <sergio....@gmail.com>
> Link: https://github.com/Rust-for-Linux/linux/issues/504
Hello!
<sergio....@gmail.com> 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 one symbol with the longest possible length.
>
> The first test verify that functions with names of the created
> symbol, can be called or not.
>
> The second test, verify that the symbols are created (or
> not) in the kernel symbol table.
>
> [1] https://lore.kernel.org/lkml/20220802015052...@kernel.org/
> [2] https://lore.kernel.org/lkml/20240605032120...@kernel.org/
>
> Tested-by: Martin Rodriguez Reboredo <yako...@gmail.com>
> Reviewed-by: Shuah Khan <sk...@linuxfoundation.org>
> Reviewed-by: Rae Moar <rm...@google.com>
> Signed-off-by: Sergio González Collado <sergio....@gmail.com>
> Link: https://github.com/Rust-for-Linux/linux/issues/504
Thanks for fixing the typo and this new version! This patch still does
not apply cleanly in the Makefile for me. Have you rebased it on the
kselftest/kunit branch? I also have a few more questions that I just
noticed.
Thanks!
-Rae
make a symbol with a length that exceeds the KSYM_NAME_LEN. What is
the intention for this line?
The change list that applies cleanly for me is:
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_CRC16_KUNIT_TEST) += crc16_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..2a2dd1151097
> --- /dev/null
> +++ b/lib/longest_symbol_kunit.c
> @@ -0,0 +1,84 @@
> +// 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
I don't believe you use this macro. Could probably be deleted.
+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..2a2dd1151097
> --- /dev/null
> +++ b/lib/longest_symbol_kunit.c
> @@ -0,0 +1,84 @@
> +// 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)
be deleted.
> +
> +/*Generate a symbol whose name length is 511 */
> +#define LONGEST_SYM_NAME DDDDDI(g1h2i3j4k5l6m7n)
> +
> +#define RETURN_LONGEST_SYM 0xAAAAA
> +
> +noinline int LONGEST_SYM_NAME(void);
> +noinline int LONGEST_SYM_NAME(void)
> +{
> + return RETURN_LONGEST_SYM;
> +}
> +
> +_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)));
__stringify(KSYM_NAME) to give the maximum length?
Also, I get an error because the length of LONGEST_SYM_NAME is 512.
The error is produced by this code:
https://elixir.bootlin.com/linux/v6.13.1/source/scripts/kallsyms.c#L152
and alerts if the symbol length is >= to KSYM_NAME_LEN. That is fine
as long as that is the intention of this test to produce a warning. Or
should this warning change to be "> KSYM_NAME_LEN" if usage of symbols
that are the maximum length is allowed?
Sergio González Collado
Feb 17, 2025, 3:30:16 PM2/17/25
to Rae Moar, David Gow, linux-k...@vger.kernel.org, kuni...@googlegroups.com, Miguel Ojeda, Alex Gaynor, Boqun Feng, Gary Guo, Björn Roy Baron, Benno Lossin, Andreas Hindborg, Alice Ryhl, David Rheinsberg, rust-fo...@vger.kernel.org, x...@kernel.org, Martin Rodriguez Reboredo, Shuah Khan
Hello,
That will define how much space to write a symbol. I'm also not
familiar with that test, but I know had to be fixed:
https://lore.kernel.org/lkml/Y9ES4UKl%2F+D...@gmail.com/T/#m3ef0e12bb834d01ed1ebdcae12ef5f2add342077
I will create a new rebased version of the patch.
> >
> > diff --git a/lib/longest_symbol_kunit.c b/lib/longest_symbol_kunit.c
> > new file mode 100644
> > index 000000000000..2a2dd1151097
> > --- /dev/null
> > +++ b/lib/longest_symbol_kunit.c
> > @@ -0,0 +1,84 @@
> > +// 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
>
> I don't believe you use this macro. Could probably be deleted.
>
This macro should work out of the box by means of the pr_*() macros:
https://docs.kernel.org/core-api/printk-basics.html#c.pr_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)
>
> I don't think you use this anymore with the new changes. Can probably
> be deleted.
>
Indeed, I totally overlooked that.
>
> > +
> > +/*Generate a symbol whose name length is 511 */
> > +#define LONGEST_SYM_NAME DDDDDI(g1h2i3j4k5l6m7n)
> > +
> > +#define RETURN_LONGEST_SYM 0xAAAAA
> > +
> > +noinline int LONGEST_SYM_NAME(void);
> > +noinline int LONGEST_SYM_NAME(void)
> > +{
> > + return RETURN_LONGEST_SYM;
> > +}
> > +
> > +_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)));
>
> Should this error return __stringify(KSYM_NAME_LEN) instead of
> __stringify(KSYM_NAME) to give the maximum length?
>
It is done on purpose to show what the actual symbol is. Under some
conditions the names can incorporate
prefix symbols, for example:
https://lore.kernel.org/lkml/202210281944...@infradead.org/,
if this happens it will be easier to spot what is going on.
>
> Also, I get an error because the length of LONGEST_SYM_NAME is 512.
> The error is produced by this code:
> https://elixir.bootlin.com/linux/v6.13.1/source/scripts/kallsyms.c#L152
> and alerts if the symbol length is >= to KSYM_NAME_LEN. That is fine
> as long as that is the intention of this test to produce a warning. Or
> should this warning change to be "> KSYM_NAME_LEN" if usage of symbols
> that are the maximum length is allowed?
>
Indeed that is expected, as the limit is reached. I think it may not
be really needed to update the condition to "> KSYM_NAME_LEN".
Thanks a lot for your remarks.
Cheers!
familiar with that test, but I know had to be fixed:
https://lore.kernel.org/lkml/Y9ES4UKl%2F+D...@gmail.com/T/#m3ef0e12bb834d01ed1ebdcae12ef5f2add342077
> >
> > diff --git a/lib/longest_symbol_kunit.c b/lib/longest_symbol_kunit.c
> > new file mode 100644
> > index 000000000000..2a2dd1151097
> > --- /dev/null
> > +++ b/lib/longest_symbol_kunit.c
> > @@ -0,0 +1,84 @@
> > +// 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
>
> I don't believe you use this macro. Could probably be deleted.
>
https://docs.kernel.org/core-api/printk-basics.html#c.pr_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)
>
> I don't think you use this anymore with the new changes. Can probably
> be deleted.
>
>
> > +
> > +/*Generate a symbol whose name length is 511 */
> > +#define LONGEST_SYM_NAME DDDDDI(g1h2i3j4k5l6m7n)
> > +
> > +#define RETURN_LONGEST_SYM 0xAAAAA
> > +
> > +noinline int LONGEST_SYM_NAME(void);
> > +noinline int LONGEST_SYM_NAME(void)
> > +{
> > + return RETURN_LONGEST_SYM;
> > +}
> > +
> > +_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)));
>
> Should this error return __stringify(KSYM_NAME_LEN) instead of
> __stringify(KSYM_NAME) to give the maximum length?
>
conditions the names can incorporate
prefix symbols, for example:
https://lore.kernel.org/lkml/202210281944...@infradead.org/,
if this happens it will be easier to spot what is going on.
>
> Also, I get an error because the length of LONGEST_SYM_NAME is 512.
> The error is produced by this code:
> https://elixir.bootlin.com/linux/v6.13.1/source/scripts/kallsyms.c#L152
> and alerts if the symbol length is >= to KSYM_NAME_LEN. That is fine
> as long as that is the intention of this test to produce a warning. Or
> should this warning change to be "> KSYM_NAME_LEN" if usage of symbols
> that are the maximum length is allowed?
>
be really needed to update the condition to "> KSYM_NAME_LEN".
Thanks a lot for your remarks.
Cheers!
Rae Moar
Feb 19, 2025, 6:10:22 PM2/19/25
to Sergio González Collado, David Gow, linux-k...@vger.kernel.org, kuni...@googlegroups.com, Miguel Ojeda, Alex Gaynor, Boqun Feng, Gary Guo, Björn Roy Baron, Benno Lossin, Andreas Hindborg, Alice Ryhl, David Rheinsberg, rust-fo...@vger.kernel.org, x...@kernel.org, Martin Rodriguez Reboredo, Shuah Khan
On Mon, Feb 17, 2025 at 3:30 PM Sergio González Collado
Hi! Thanks for your responses.
This seems good to me. Thanks for the explanation.
Right now this outputs: "Incorrect symbol len. Expected KSYM_NAME_LEN:
KSYM_NAME, but found: sizeof(snn...6m7n)"
This seems incorrect because KSYM_NAME has no value. Instead I would
expect: "Incorrect symbol len. Expected KSYM_NAME_LEN: 512, but
found: sizeof(snn...6m7n)".
>
> >
> > Also, I get an error because the length of LONGEST_SYM_NAME is 512.
> > The error is produced by this code:
> > https://elixir.bootlin.com/linux/v6.13.1/source/scripts/kallsyms.c#L152
> > and alerts if the symbol length is >= to KSYM_NAME_LEN. That is fine
> > as long as that is the intention of this test to produce a warning. Or
> > should this warning change to be "> KSYM_NAME_LEN" if usage of symbols
> > that are the maximum length is allowed?
> >
> Indeed that is expected, as the limit is reached. I think it may not
> be really needed to update the condition to "> KSYM_NAME_LEN".
>
That seems good to me.
Thanks!
-Rae
This seems good to me. Thanks for the explanation.
KSYM_NAME, but found: sizeof(snn...6m7n)"
This seems incorrect because KSYM_NAME has no value. Instead I would
expect: "Incorrect symbol len. Expected KSYM_NAME_LEN: 512, but
found: sizeof(snn...6m7n)".
>
> >
> > Also, I get an error because the length of LONGEST_SYM_NAME is 512.
> > The error is produced by this code:
> > https://elixir.bootlin.com/linux/v6.13.1/source/scripts/kallsyms.c#L152
> > and alerts if the symbol length is >= to KSYM_NAME_LEN. That is fine
> > as long as that is the intention of this test to produce a warning. Or
> > should this warning change to be "> KSYM_NAME_LEN" if usage of symbols
> > that are the maximum length is allowed?
> >
> Indeed that is expected, as the limit is reached. I think it may not
> be really needed to update the condition to "> KSYM_NAME_LEN".
>
Thanks!
-Rae
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