Some unit tests intentionally trigger warning backtraces by passing bad parameters to API functions. Such unit tests typically check the return value from those calls, not the existence of the warning backtrace.

Such intentionally generated warning backtraces are neither desirable nor useful for a number of reasons. - They can result in overlooked real problems. - A warning that suddenly starts to show up in unit tests needs to be investigated and has to be marked to be ignored, for example by adjusting filter scripts. Such filters are ad-hoc because there is no real standard format for warnings. On top of that, such filter scripts would require constant maintenance.

One option to address problem would be to add messages such as "expected warning backtraces start / end here" to the kernel log. However, that would again require filter scripts, it might result in missing real problematic warning backtraces triggered while the test is running, and the irrelevant backtrace(s) would still clog the kernel log.

Solve the problem by providing a means to identify and suppress specific warning backtraces while executing test code.

Cc: Dan Carpenter dan.carpenter@linaro.org Cc: Daniel Diaz daniel.diaz@linaro.org Cc: Naresh Kamboju naresh.kamboju@linaro.org Cc: Kees Cook keescook@chromium.org Signed-off-by: Guenter Roeck linux@roeck-us.net --- include/asm-generic/bug.h | 16 +++++++++--- include/kunit/bug.h | 51 +++++++++++++++++++++++++++++++++++++++ include/kunit/test.h | 1 + include/linux/bug.h | 13 ++++++++++ lib/bug.c | 51 ++++++++++++++++++++++++++++++++++++--- lib/kunit/Makefile | 6 +++-- lib/kunit/bug.c | 40 ++++++++++++++++++++++++++++++ 7 files changed, 169 insertions(+), 9 deletions(-) create mode 100644 include/kunit/bug.h create mode 100644 lib/kunit/bug.c

diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h index 6e794420bd39..c170b6477689 100644 --- a/include/asm-generic/bug.h +++ b/include/asm-generic/bug.h @@ -18,6 +18,7 @@ #endif

#ifndef __ASSEMBLY__ +#include <kunit/bug.h> #include <linux/panic.h> #include <linux/printk.h>

@@ -39,8 +40,14 @@ struct bug_entry { #ifdef CONFIG_DEBUG_BUGVERBOSE #ifndef CONFIG_GENERIC_BUG_RELATIVE_POINTERS const char *file; +#ifdef HAVE_BUG_FUNCTION + const char *function; +#endif #else signed int file_disp; +#ifdef HAVE_BUG_FUNCTION + signed int function_disp; +#endif #endif unsigned short line; #endif @@ -96,15 +103,18 @@ extern __printf(1, 2) void __warn_printk(const char *fmt, ...); #define __WARN() __WARN_printf(TAINT_WARN, NULL) #define __WARN_printf(taint, arg...) do { \ instrumentation_begin(); \ - warn_slowpath_fmt(__FILE__, __LINE__, taint, arg); \ + if (!IS_SUPPRESSED_WARNING(__func__)) \ + warn_slowpath_fmt(__FILE__, __LINE__, taint, arg);\ instrumentation_end(); \ } while (0) #else #define __WARN() __WARN_FLAGS(BUGFLAG_TAINT(TAINT_WARN)) #define __WARN_printf(taint, arg...) do { \ instrumentation_begin(); \ - __warn_printk(arg); \ - __WARN_FLAGS(BUGFLAG_NO_CUT_HERE | BUGFLAG_TAINT(taint));\ + if (!IS_SUPPRESSED_WARNING(__func__)) { \ + __warn_printk(arg); \ + __WARN_FLAGS(BUGFLAG_NO_CUT_HERE | BUGFLAG_TAINT(taint));\ + } \ instrumentation_end(); \ } while (0) #define WARN_ON_ONCE(condition) ({ \ diff --git a/include/kunit/bug.h b/include/kunit/bug.h new file mode 100644 index 000000000000..1e34da961599 --- /dev/null +++ b/include/kunit/bug.h @@ -0,0 +1,51 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * KUnit helpers for backtrace suppression + * + * Copyright (c) 2024 Guenter Roeck linux@roeck-us.net + */ + +#ifndef _KUNIT_BUG_H +#define _KUNIT_BUG_H + +#ifndef __ASSEMBLY__ + +#include <linux/kconfig.h> + +#if IS_ENABLED(CONFIG_KUNIT) + +#include <linux/stringify.h> +#include <linux/types.h> + +struct __suppressed_warning { + struct list_head node; + const char *function; +}; + +void __start_suppress_warning(struct __suppressed_warning *warning); +void __end_suppress_warning(struct __suppressed_warning *warning); +bool __is_suppressed_warning(const char *function); + +#define DEFINE_SUPPRESSED_WARNING(func) \ + struct __suppressed_warning __kunit_suppress_##func = \ + { .function = __stringify(func) } + +#define START_SUPPRESSED_WARNING(func) \ + __start_suppress_warning(&__kunit_suppress_##func) + +#define END_SUPPRESSED_WARNING(func) \ + __end_suppress_warning(&__kunit_suppress_##func) + +#define IS_SUPPRESSED_WARNING(func) \ + __is_suppressed_warning(func) + +#else /* CONFIG_KUNIT */ + +#define DEFINE_SUPPRESSED_WARNING(func) +#define START_SUPPRESSED_WARNING(func) +#define END_SUPPRESSED_WARNING(func) +#define IS_SUPPRESSED_WARNING(func) (false) + +#endif /* CONFIG_KUNIT */ +#endif /* __ASSEMBLY__ */ +#endif /* _KUNIT_BUG_H */ diff --git a/include/kunit/test.h b/include/kunit/test.h index fcb4a4940ace..894c9fd1495d 100644 --- a/include/kunit/test.h +++ b/include/kunit/test.h @@ -10,6 +10,7 @@ #define _KUNIT_TEST_H

#include <kunit/assert.h> +#include <kunit/bug.h> #include <kunit/try-catch.h>

#include <linux/args.h> diff --git a/include/linux/bug.h b/include/linux/bug.h index 348acf2558f3..c668762dc76a 100644 --- a/include/linux/bug.h +++ b/include/linux/bug.h @@ -36,6 +36,9 @@ static inline int is_warning_bug(const struct bug_entry *bug) return bug->flags & BUGFLAG_WARNING; }

+void bug_get_file_function_line(struct bug_entry *bug, const char **file, + const char **function, unsigned int *line); + void bug_get_file_line(struct bug_entry *bug, const char **file, unsigned int *line);

@@ -62,6 +65,16 @@ static inline enum bug_trap_type report_bug(unsigned long bug_addr, }

struct bug_entry; +static inline void bug_get_file_function_line(struct bug_entry *bug, + const char **file, + const char **function, + unsigned int *line) +{ + *file = NULL; + *function = NULL; + *line = 0; +} + static inline void bug_get_file_line(struct bug_entry *bug, const char **file, unsigned int *line) { diff --git a/lib/bug.c b/lib/bug.c index e0ff21989990..6b85d4042e07 100644 --- a/lib/bug.c +++ b/lib/bug.c @@ -26,6 +26,14 @@ when CONFIG_DEBUG_BUGVERBOSE is not enabled, so you must generate the values accordingly.

+ 2a.Optionally implement support for the "function" entry in struct + bug_entry. This entry must point to the name of the function triggering + the warning or bug trap (normally __func__). This is only needed if + both CONFIG_DEBUG_BUGVERBOSE and CONFIG_KUNIT are enabled and if + the architecture wants to implement support for suppressing warning + backtraces. The architecture must define HAVE_BUG_FUNCTION if it adds + pointers to function names to struct bug_entry. + 3. Implement the trap - In the illegal instruction trap handler (typically), verify that the fault was in kernel mode, and call report_bug() @@ -127,14 +135,21 @@ static inline struct bug_entry *module_find_bug(unsigned long bugaddr) } #endif

-void bug_get_file_line(struct bug_entry *bug, const char **file, - unsigned int *line) +void bug_get_file_function_line(struct bug_entry *bug, const char **file, + const char **function, unsigned int *line) { + *function = NULL; #ifdef CONFIG_DEBUG_BUGVERBOSE #ifdef CONFIG_GENERIC_BUG_RELATIVE_POINTERS *file = (const char *)&bug->file_disp + bug->file_disp; +#ifdef HAVE_BUG_FUNCTION + *function = (const char *)&bug->function_disp + bug->function_disp; +#endif #else *file = bug->file; +#ifdef HAVE_BUG_FUNCTION + *function = bug->function; +#endif #endif *line = bug->line; #else @@ -143,6 +158,13 @@ void bug_get_file_line(struct bug_entry *bug, const char **file, #endif }

+void bug_get_file_line(struct bug_entry *bug, const char **file, unsigned int *line) +{ + const char *function; + + bug_get_file_function_line(bug, file, &function, line); +} + struct bug_entry *find_bug(unsigned long bugaddr) { struct bug_entry *bug; @@ -157,8 +179,9 @@ struct bug_entry *find_bug(unsigned long bugaddr) static enum bug_trap_type __report_bug(unsigned long bugaddr, struct pt_regs *regs) { struct bug_entry *bug; - const char *file; + const char *file, *function; unsigned line, warning, once, done; + char __maybe_unused sym[KSYM_SYMBOL_LEN];

if (!is_valid_bugaddr(bugaddr)) return BUG_TRAP_TYPE_NONE; @@ -169,12 +192,32 @@ static enum bug_trap_type __report_bug(unsigned long bugaddr, struct pt_regs *re

disable_trace_on_warning();

- bug_get_file_line(bug, &file, &line); + bug_get_file_function_line(bug, &file, &function, &line); +#if IS_ENABLED(CONFIG_KUNIT) && defined(CONFIG_KALLSYMS) + if (!function) { + /* + * This will be seen if report_bug is called on an architecture + * with no architecture-specific support for suppressing warning + * backtraces, if CONFIG_DEBUG_BUGVERBOSE is not enabled, or if + * the calling code is from assembler which does not record a + * function name. Extracting the function name from the bug + * address is less than perfect since compiler optimization may + * result in 'bugaddr' pointing to a function which does not + * actually trigger the warning, but it is better than no + * suppression at all. + */ + sprint_symbol_no_offset(sym, bugaddr); + function = sym; + } +#endif /* IS_ENABLED(CONFIG_KUNIT) && defined(CONFIG_KALLSYMS) */

warning = (bug->flags & BUGFLAG_WARNING) != 0; once = (bug->flags & BUGFLAG_ONCE) != 0; done = (bug->flags & BUGFLAG_DONE) != 0;

+ if (warning && IS_SUPPRESSED_WARNING(function)) + return BUG_TRAP_TYPE_WARN; + if (warning && once) { if (done) return BUG_TRAP_TYPE_WARN; diff --git a/lib/kunit/Makefile b/lib/kunit/Makefile index 309659a32a78..545b57c3be48 100644 --- a/lib/kunit/Makefile +++ b/lib/kunit/Makefile @@ -14,8 +14,10 @@ ifeq ($(CONFIG_KUNIT_DEBUGFS),y) kunit-objs += debugfs.o endif

-# KUnit 'hooks' are built-in even when KUnit is built as a module. -obj-y += hooks.o +# KUnit 'hooks' and bug handling are built-in even when KUnit is built +# as a module. +obj-y += hooks.o \ + bug.o

obj-$(CONFIG_KUNIT_TEST) += kunit-test.o

diff --git a/lib/kunit/bug.c b/lib/kunit/bug.c new file mode 100644 index 000000000000..f93544d7a9d1 --- /dev/null +++ b/lib/kunit/bug.c @@ -0,0 +1,40 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * KUnit helpers for backtrace suppression + * + * Copyright (c) 2024 Guenter Roeck linux@roeck-us.net + */ + +#include <kunit/bug.h> +#include <linux/export.h> +#include <linux/list.h> +#include <linux/string.h> + +static LIST_HEAD(suppressed_warnings); + +void __start_suppress_warning(struct __suppressed_warning *warning) +{ + list_add(&warning->node, &suppressed_warnings); +} +EXPORT_SYMBOL_GPL(__start_suppress_warning); + +void __end_suppress_warning(struct __suppressed_warning *warning) +{ + list_del(&warning->node); +} +EXPORT_SYMBOL_GPL(__end_suppress_warning); + +bool __is_suppressed_warning(const char *function) +{ + struct __suppressed_warning *warning; + + if (!function) + return false; + + list_for_each_entry(warning, &suppressed_warnings, node) { + if (!strcmp(function, warning->function)) + return true; + } + return false; +} +EXPORT_SYMBOL_GPL(__is_suppressed_warning);

Count suppressed warning backtraces to enable code which suppresses warning backtraces to check if the expected backtrace(s) have been observed.

Using atomics for the backtrace count resulted in build errors on some architectures due to include file recursion, so use a plain integer for now.

Signed-off-by: Guenter Roeck linux@roeck-us.net --- include/kunit/bug.h | 7 ++++++- lib/kunit/bug.c | 4 +++- 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/include/kunit/bug.h b/include/kunit/bug.h index 1e34da961599..2097a854ac8c 100644 --- a/include/kunit/bug.h +++ b/include/kunit/bug.h @@ -20,6 +20,7 @@ struct __suppressed_warning { struct list_head node; const char *function; + int counter; };

void __start_suppress_warning(struct __suppressed_warning *warning); @@ -28,7 +29,7 @@ bool __is_suppressed_warning(const char *function);

#define DEFINE_SUPPRESSED_WARNING(func) \ struct __suppressed_warning __kunit_suppress_##func = \ - { .function = __stringify(func) } + { .function = __stringify(func), .counter = 0 }

#define START_SUPPRESSED_WARNING(func) \ __start_suppress_warning(&__kunit_suppress_##func) @@ -39,12 +40,16 @@ bool __is_suppressed_warning(const char *function); #define IS_SUPPRESSED_WARNING(func) \ __is_suppressed_warning(func)

+#define SUPPRESSED_WARNING_COUNT(func) \ + (__kunit_suppress_##func.counter) + #else /* CONFIG_KUNIT */

#define DEFINE_SUPPRESSED_WARNING(func) #define START_SUPPRESSED_WARNING(func) #define END_SUPPRESSED_WARNING(func) #define IS_SUPPRESSED_WARNING(func) (false) +#define SUPPRESSED_WARNING_COUNT(func) (0)

#endif /* CONFIG_KUNIT */ #endif /* __ASSEMBLY__ */ diff --git a/lib/kunit/bug.c b/lib/kunit/bug.c index f93544d7a9d1..13b3d896c114 100644 --- a/lib/kunit/bug.c +++ b/lib/kunit/bug.c @@ -32,8 +32,10 @@ bool __is_suppressed_warning(const char *function) return false;

list_for_each_entry(warning, &suppressed_warnings, node) { - if (!strcmp(function, warning->function)) + if (!strcmp(function, warning->function)) { + warning->counter++; return true; + } } return false; }

Add unit tests to verify that warning backtrace suppression works.

If backtrace suppression does _not_ work, the unit tests will likely trigger unsuppressed backtraces, which should actually help to get the affected architectures / platforms fixed.

Signed-off-by: Guenter Roeck linux@roeck-us.net --- lib/kunit/Makefile | 3 +- lib/kunit/backtrace-suppression-test.c | 104 +++++++++++++++++++++++++ 2 files changed, 106 insertions(+), 1 deletion(-) create mode 100644 lib/kunit/backtrace-suppression-test.c

diff --git a/lib/kunit/Makefile b/lib/kunit/Makefile index 545b57c3be48..6a44d2b54ea9 100644 --- a/lib/kunit/Makefile +++ b/lib/kunit/Makefile @@ -19,7 +19,8 @@ endif obj-y += hooks.o \ bug.o

-obj-$(CONFIG_KUNIT_TEST) += kunit-test.o +obj-$(CONFIG_KUNIT_TEST) += kunit-test.o \ + backtrace-suppression-test.o

# string-stream-test compiles built-in only. ifeq ($(CONFIG_KUNIT_TEST),y) diff --git a/lib/kunit/backtrace-suppression-test.c b/lib/kunit/backtrace-suppression-test.c new file mode 100644 index 000000000000..47c619283802 --- /dev/null +++ b/lib/kunit/backtrace-suppression-test.c @@ -0,0 +1,104 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * KUnit test for suppressing warning tracebacks + * + * Copyright (C) 2024, Guenter Roeck + * Author: Guenter Roeck linux@roeck-us.net + */ + +#include <kunit/test.h> +#include <linux/bug.h> + +static void backtrace_suppression_test_warn_direct(struct kunit *test) +{ + DEFINE_SUPPRESSED_WARNING(backtrace_suppression_test_warn_direct); + + START_SUPPRESSED_WARNING(backtrace_suppression_test_warn_direct); + WARN(1, "This backtrace should be suppressed"); + END_SUPPRESSED_WARNING(backtrace_suppression_test_warn_direct); + + KUNIT_EXPECT_EQ(test, SUPPRESSED_WARNING_COUNT(backtrace_suppression_test_warn_direct), 1); +} + +static void trigger_backtrace_warn(void) +{ + WARN(1, "This backtrace should be suppressed"); +} + +static void backtrace_suppression_test_warn_indirect(struct kunit *test) +{ + DEFINE_SUPPRESSED_WARNING(trigger_backtrace_warn); + + START_SUPPRESSED_WARNING(trigger_backtrace_warn); + trigger_backtrace_warn(); + END_SUPPRESSED_WARNING(trigger_backtrace_warn); + + KUNIT_EXPECT_EQ(test, SUPPRESSED_WARNING_COUNT(trigger_backtrace_warn), 1); +} + +static void backtrace_suppression_test_warn_multi(struct kunit *test) +{ + DEFINE_SUPPRESSED_WARNING(trigger_backtrace_warn); + DEFINE_SUPPRESSED_WARNING(backtrace_suppression_test_warn_multi); + + START_SUPPRESSED_WARNING(backtrace_suppression_test_warn_multi); + START_SUPPRESSED_WARNING(trigger_backtrace_warn); + WARN(1, "This backtrace should be suppressed"); + trigger_backtrace_warn(); + END_SUPPRESSED_WARNING(trigger_backtrace_warn); + END_SUPPRESSED_WARNING(backtrace_suppression_test_warn_multi); + + KUNIT_EXPECT_EQ(test, SUPPRESSED_WARNING_COUNT(backtrace_suppression_test_warn_multi), 1); + KUNIT_EXPECT_EQ(test, SUPPRESSED_WARNING_COUNT(trigger_backtrace_warn), 1); +} + +static void backtrace_suppression_test_warn_on_direct(struct kunit *test) +{ + DEFINE_SUPPRESSED_WARNING(backtrace_suppression_test_warn_on_direct); + + if (!IS_ENABLED(CONFIG_DEBUG_BUGVERBOSE) && !IS_ENABLED(CONFIG_KALLSYMS)) + kunit_skip(test, "requires CONFIG_DEBUG_BUGVERBOSE or CONFIG_KALLSYMS"); + + START_SUPPRESSED_WARNING(backtrace_suppression_test_warn_on_direct); + WARN_ON(1); + END_SUPPRESSED_WARNING(backtrace_suppression_test_warn_on_direct); + + KUNIT_EXPECT_EQ(test, + SUPPRESSED_WARNING_COUNT(backtrace_suppression_test_warn_on_direct), 1); +} + +static void trigger_backtrace_warn_on(void) +{ + WARN_ON(1); +} + +static void backtrace_suppression_test_warn_on_indirect(struct kunit *test) +{ + DEFINE_SUPPRESSED_WARNING(trigger_backtrace_warn_on); + + if (!IS_ENABLED(CONFIG_DEBUG_BUGVERBOSE)) + kunit_skip(test, "requires CONFIG_DEBUG_BUGVERBOSE"); + + START_SUPPRESSED_WARNING(trigger_backtrace_warn_on); + trigger_backtrace_warn_on(); + END_SUPPRESSED_WARNING(trigger_backtrace_warn_on); + + KUNIT_EXPECT_EQ(test, SUPPRESSED_WARNING_COUNT(trigger_backtrace_warn_on), 1); +} + +static struct kunit_case backtrace_suppression_test_cases[] = { + KUNIT_CASE(backtrace_suppression_test_warn_direct), + KUNIT_CASE(backtrace_suppression_test_warn_indirect), + KUNIT_CASE(backtrace_suppression_test_warn_multi), + KUNIT_CASE(backtrace_suppression_test_warn_on_direct), + KUNIT_CASE(backtrace_suppression_test_warn_on_indirect), + {} +}; + +static struct kunit_suite backtrace_suppression_test_suite = { + .name = "backtrace-suppression-test", + .test_cases = backtrace_suppression_test_cases, +}; +kunit_test_suites(&backtrace_suppression_test_suite); + +MODULE_LICENSE("GPL");

Document API functions for suppressing warning backtraces.

Signed-off-by: Guenter Roeck linux@roeck-us.net --- Documentation/dev-tools/kunit/usage.rst | 30 ++++++++++++++++++++++++- 1 file changed, 29 insertions(+), 1 deletion(-)

diff --git a/Documentation/dev-tools/kunit/usage.rst b/Documentation/dev-tools/kunit/usage.rst index 22955d56b379..8d3d36d4103d 100644 --- a/Documentation/dev-tools/kunit/usage.rst +++ b/Documentation/dev-tools/kunit/usage.rst @@ -157,6 +157,34 @@ Alternatively, one can take full control over the error message by using if (some_setup_function()) KUNIT_FAIL(test, "Failed to setup thing for testing");

+Suppressing warning backtraces +------------------------------ + +Some unit tests trigger warning backtraces either intentionally or as side +effect. Such backtraces are normally undesirable since they distract from +the actual test and may result in the impression that there is a problem. + +Such backtraces can be suppressed. To suppress a backtrace in some_function(), +use the following code. + +.. code-block:: c + + static void some_test(struct kunit *test) + { + DEFINE_SUPPRESSED_WARNING(some_function); + + START_SUPPRESSED_WARNING(some_function); + trigger_backtrace(); + END_SUPPRESSED_WARNING(some_function); + } + +SUPPRESSED_WARNING_COUNT() returns the number of suppressed backtraces. If the +suppressed backtrace was triggered on purpose, this can be used to check if +the backtrace was actually triggered. + +.. code-block:: c + + KUNIT_EXPECT_EQ(test, SUPPRESSED_WARNING_COUNT(some_function), 1);

Test Suites ~~~~~~~~~~~ @@ -857,4 +885,4 @@ For example: dev_managed_string = devm_kstrdup(fake_device, "Hello, World!");

// Everything is cleaned up automatically when the test ends. - } \ No newline at end of file + }

The drm_test_rect_calc_hscale and drm_test_rect_calc_vscale unit tests intentionally trigger warning backtraces by providing bad parameters to the tested functions. What is tested is the return value, not the existence of a warning backtrace. Suppress the backtraces to avoid clogging the kernel log.

Signed-off-by: Guenter Roeck linux@roeck-us.net --- drivers/gpu/drm/tests/drm_rect_test.c | 6 ++++++ 1 file changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/tests/drm_rect_test.c b/drivers/gpu/drm/tests/drm_rect_test.c index 76332cd2ead8..75614cb4deb5 100644 --- a/drivers/gpu/drm/tests/drm_rect_test.c +++ b/drivers/gpu/drm/tests/drm_rect_test.c @@ -406,22 +406,28 @@ KUNIT_ARRAY_PARAM(drm_rect_scale, drm_rect_scale_cases, drm_rect_scale_case_desc

static void drm_test_rect_calc_hscale(struct kunit *test) { + DEFINE_SUPPRESSED_WARNING(drm_calc_scale); const struct drm_rect_scale_case *params = test->param_value; int scaling_factor;

+ START_SUPPRESSED_WARNING(drm_calc_scale); scaling_factor = drm_rect_calc_hscale(&params->src, &params->dst, params->min_range, params->max_range); + END_SUPPRESSED_WARNING(drm_calc_scale);

KUNIT_EXPECT_EQ(test, scaling_factor, params->expected_scaling_factor); }

static void drm_test_rect_calc_vscale(struct kunit *test) { + DEFINE_SUPPRESSED_WARNING(drm_calc_scale); const struct drm_rect_scale_case *params = test->param_value; int scaling_factor;

+ START_SUPPRESSED_WARNING(drm_calc_scale); scaling_factor = drm_rect_calc_vscale(&params->src, &params->dst, params->min_range, params->max_range); + END_SUPPRESSED_WARNING(drm_calc_scale);

KUNIT_EXPECT_EQ(test, scaling_factor, params->expected_scaling_factor); }

Add name of functions triggering warning backtraces to the __bug_table object section to enable support for suppressing WARNING backtraces.

To limit image size impact, the pointer to the function name is only added to the __bug_table section if both CONFIG_KUNIT and CONFIG_DEBUG_BUGVERBOSE are enabled. Otherwise, the __func__ assembly parameter is replaced with a (dummy) NULL parameter to avoid an image size increase due to unused __func__ entries (this is necessary because __func__ is not a define but a virtual variable).

Signed-off-by: Guenter Roeck linux@roeck-us.net --- arch/x86/include/asm/bug.h | 21 ++++++++++++++++----- 1 file changed, 16 insertions(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/bug.h b/arch/x86/include/asm/bug.h index a3ec87d198ac..d87bf8bab238 100644 --- a/arch/x86/include/asm/bug.h +++ b/arch/x86/include/asm/bug.h @@ -23,18 +23,28 @@

#ifdef CONFIG_DEBUG_BUGVERBOSE

+#if IS_ENABLED(CONFIG_KUNIT) +# define HAVE_BUG_FUNCTION +# define __BUG_FUNC_PTR __BUG_REL(%c1) +# define __BUG_FUNC __func__ +#else +# define __BUG_FUNC_PTR +# define __BUG_FUNC NULL +#endif /* IS_ENABLED(CONFIG_KUNIT) */ + #define _BUG_FLAGS(ins, flags, extra) \ do { \ asm_inline volatile("1:\t" ins "\n" \ ".pushsection __bug_table,"aw"\n" \ "2:\t" __BUG_REL(1b) "\t# bug_entry::bug_addr\n" \ "\t" __BUG_REL(%c0) "\t# bug_entry::file\n" \ - "\t.word %c1" "\t# bug_entry::line\n" \ - "\t.word %c2" "\t# bug_entry::flags\n" \ - "\t.org 2b+%c3\n" \ + "\t" __BUG_FUNC_PTR "\t# bug_entry::function\n" \ + "\t.word %c2" "\t# bug_entry::line\n" \ + "\t.word %c3" "\t# bug_entry::flags\n" \ + "\t.org 2b+%c4\n" \ ".popsection\n" \ extra \ - : : "i" (__FILE__), "i" (__LINE__), \ + : : "i" (__FILE__), "i" (__BUG_FUNC), "i" (__LINE__),\ "i" (flags), \ "i" (sizeof(struct bug_entry))); \ } while (0) @@ -80,7 +90,8 @@ do { \ do { \ __auto_type __flags = BUGFLAG_WARNING|(flags); \ instrumentation_begin(); \ - _BUG_FLAGS(ASM_UD2, __flags, ASM_REACHABLE); \ + if (!IS_SUPPRESSED_WARNING(__func__)) \ + _BUG_FLAGS(ASM_UD2, __flags, ASM_REACHABLE); \ instrumentation_end(); \ } while (0)

Add name of functions triggering warning backtraces to the __bug_table object section to enable support for suppressing WARNING backtraces.

To limit image size impact, the pointer to the function name is only added to the __bug_table section if both CONFIG_KUNIT and CONFIG_DEBUG_BUGVERBOSE are enabled. Otherwise, the __func__ assembly parameter is replaced with a (dummy) NULL parameter to avoid an image size increase due to unused __func__ entries (this is necessary because __func__ is not a define but a virtual variable).

Signed-off-by: Guenter Roeck linux@roeck-us.net --- arch/loongarch/include/asm/bug.h | 38 +++++++++++++++++++++++--------- 1 file changed, 27 insertions(+), 11 deletions(-)

diff --git a/arch/loongarch/include/asm/bug.h b/arch/loongarch/include/asm/bug.h index d4ca3ba25418..25f2b5ae7702 100644 --- a/arch/loongarch/include/asm/bug.h +++ b/arch/loongarch/include/asm/bug.h @@ -3,47 +3,63 @@ #define __ASM_BUG_H

#include <asm/break.h> +#include <kunit/bug.h> #include <linux/stringify.h>

#ifndef CONFIG_DEBUG_BUGVERBOSE -#define _BUGVERBOSE_LOCATION(file, line) +#define _BUGVERBOSE_LOCATION(file, func, line) #else -#define __BUGVERBOSE_LOCATION(file, line) \ +#if IS_ENABLED(CONFIG_KUNIT) +# define HAVE_BUG_FUNCTION +# define __BUG_FUNC_PTR(func) .long func - .; +#else +# define __BUG_FUNC_PTR(func) +#endif + +#define __BUGVERBOSE_LOCATION(file, func, line) \ .pushsection .rodata.str, "aMS", @progbits, 1; \ 10002: .string file; \ .popsection; \ \ .long 10002b - .; \ + __BUG_FUNC_PTR(func) \ .short line; -#define _BUGVERBOSE_LOCATION(file, line) __BUGVERBOSE_LOCATION(file, line) +#define _BUGVERBOSE_LOCATION(file, func, line) __BUGVERBOSE_LOCATION(file, func, line) #endif

#ifndef CONFIG_GENERIC_BUG -#define __BUG_ENTRY(flags) +#define __BUG_ENTRY(flags, func) #else -#define __BUG_ENTRY(flags) \ +#define __BUG_ENTRY(flags, func) \ .pushsection __bug_table, "aw"; \ .align 2; \ 10000: .long 10001f - .; \ - _BUGVERBOSE_LOCATION(__FILE__, __LINE__) \ + _BUGVERBOSE_LOCATION(__FILE__, func, __LINE__) \ .short flags; \ .popsection; \ 10001: #endif

-#define ASM_BUG_FLAGS(flags) \ - __BUG_ENTRY(flags) \ +#define ASM_BUG_FLAGS(flags, func) \ + __BUG_ENTRY(flags, func) \ break BRK_BUG

-#define ASM_BUG() ASM_BUG_FLAGS(0) +#define ASM_BUG() ASM_BUG_FLAGS(0, .) + +#ifdef HAVE_BUG_FUNCTION +# define __BUG_FUNC __func__ +#else +# define __BUG_FUNC NULL +#endif

#define __BUG_FLAGS(flags) \ - asm_inline volatile (__stringify(ASM_BUG_FLAGS(flags))); + asm_inline volatile (__stringify(ASM_BUG_FLAGS(flags, %0)) : : "i" (__BUG_FUNC));

#define __WARN_FLAGS(flags) \ do { \ instrumentation_begin(); \ - __BUG_FLAGS(BUGFLAG_WARNING|(flags)); \ + if (!IS_SUPPRESSED_WARNING(__func__)) \ + __BUG_FLAGS(BUGFLAG_WARNING|(flags)); \ instrumentation_end(); \ } while (0)

Add name of functions triggering warning backtraces to the __bug_table object section to enable support for suppressing WARNING backtraces.

To limit image size impact, the pointer to the function name is only added to the __bug_table section if both CONFIG_KUNIT and CONFIG_DEBUG_BUGVERBOSE are enabled. Otherwise, the __func__ assembly parameter is replaced with a (dummy) NULL parameter to avoid an image size increase due to unused __func__ entries (this is necessary because __func__ is not a define but a virtual variable).

Signed-off-by: Guenter Roeck linux@roeck-us.net --- arch/sh/include/asm/bug.h | 26 ++++++++++++++++++++++---- 1 file changed, 22 insertions(+), 4 deletions(-)

diff --git a/arch/sh/include/asm/bug.h b/arch/sh/include/asm/bug.h index 05a485c4fabc..cadc335eb759 100644 --- a/arch/sh/include/asm/bug.h +++ b/arch/sh/include/asm/bug.h @@ -24,21 +24,36 @@ * The offending file and line are encoded in the __bug_table section. */ #ifdef CONFIG_DEBUG_BUGVERBOSE + +#if IS_ENABLED(CONFIG_KUNIT) +# define HAVE_BUG_FUNCTION +# define __BUG_FUNC_PTR "\t.long %O2\n" +#else +# define __BUG_FUNC_PTR +#endif /* IS_ENABLED(CONFIG_KUNIT) */ + #define _EMIT_BUG_ENTRY \ "\t.pushsection __bug_table,"aw"\n" \ "2:\t.long 1b, %O1\n" \ - "\t.short %O2, %O3\n" \ - "\t.org 2b+%O4\n" \ + __BUG_FUNC_PTR \ + "\t.short %O3, %O4\n" \ + "\t.org 2b+%O5\n" \ "\t.popsection\n" #else #define _EMIT_BUG_ENTRY \ "\t.pushsection __bug_table,"aw"\n" \ "2:\t.long 1b\n" \ - "\t.short %O3\n" \ - "\t.org 2b+%O4\n" \ + "\t.short %O4\n" \ + "\t.org 2b+%O5\n" \ "\t.popsection\n" #endif

+#ifdef HAVE_BUG_FUNCTION +# define __BUG_FUNC __func__ +#else +# define __BUG_FUNC NULL +#endif + #define BUG() \ do { \ __asm__ __volatile__ ( \ @@ -47,6 +62,7 @@ do { \ : \ : "n" (TRAPA_BUG_OPCODE), \ "i" (__FILE__), \ + "i" (__BUG_FUNC), \ "i" (__LINE__), "i" (0), \ "i" (sizeof(struct bug_entry))); \ unreachable(); \ @@ -60,6 +76,7 @@ do { \ : \ : "n" (TRAPA_BUG_OPCODE), \ "i" (__FILE__), \ + "i" (__BUG_FUNC), \ "i" (__LINE__), \ "i" (BUGFLAG_WARNING|(flags)), \ "i" (sizeof(struct bug_entry))); \ @@ -85,6 +102,7 @@ do { \ : \ : "n" (TRAPA_BUG_OPCODE), \ "i" (__FILE__), \ + "i" (__BUG_FUNC), \ "i" (__LINE__), \ "i" (BUGFLAG_UNWINDER), \ "i" (sizeof(struct bug_entry))); \

Add name of functions triggering warning backtraces to the __bug_table object section to enable support for suppressing WARNING backtraces.

To limit image size impact, the pointer to the function name is only added to the __bug_table section if both CONFIG_KUNIT and CONFIG_DEBUG_BUGVERBOSE are enabled. Otherwise, the __func__ assembly parameter is replaced with a (dummy) NULL parameter to avoid an image size increase due to unused __func__ entries (this is necessary because __func__ is not a define but a virtual variable).

Signed-off-by: Guenter Roeck linux@roeck-us.net --- arch/powerpc/include/asm/bug.h | 37 +++++++++++++++++++++++++--------- 1 file changed, 28 insertions(+), 9 deletions(-)

diff --git a/arch/powerpc/include/asm/bug.h b/arch/powerpc/include/asm/bug.h index 1db485aacbd9..330d4983f90e 100644 --- a/arch/powerpc/include/asm/bug.h +++ b/arch/powerpc/include/asm/bug.h @@ -14,6 +14,9 @@ .section __bug_table,"aw" 5001: .4byte \addr - . .4byte 5002f - . +#if IS_ENABLED(CONFIG_KUNIT) + .4byte 0 +#endif .short \line, \flags .org 5001b+BUG_ENTRY_SIZE .previous @@ -32,30 +35,46 @@ #endif /* verbose */

#else /* !__ASSEMBLY__ */ -/* _EMIT_BUG_ENTRY expects args %0,%1,%2,%3 to be FILE, LINE, flags and - sizeof(struct bug_entry), respectively */ +/* _EMIT_BUG_ENTRY expects args %0,%1,%2,%3,%4 to be FILE, __func__, LINE, flags + and sizeof(struct bug_entry), respectively */ #ifdef CONFIG_DEBUG_BUGVERBOSE + +#if IS_ENABLED(CONFIG_KUNIT) +# define HAVE_BUG_FUNCTION +# define __BUG_FUNC_PTR " .4byte %1 - .\n" +#else +# define __BUG_FUNC_PTR +#endif /* IS_ENABLED(CONFIG_KUNIT) */ + #define _EMIT_BUG_ENTRY \ ".section __bug_table,"aw"\n" \ "2: .4byte 1b - .\n" \ " .4byte %0 - .\n" \ - " .short %1, %2\n" \ - ".org 2b+%3\n" \ + __BUG_FUNC_PTR \ + " .short %2, %3\n" \ + ".org 2b+%4\n" \ ".previous\n" #else #define _EMIT_BUG_ENTRY \ ".section __bug_table,"aw"\n" \ "2: .4byte 1b - .\n" \ - " .short %2\n" \ - ".org 2b+%3\n" \ + " .short %3\n" \ + ".org 2b+%4\n" \ ".previous\n" #endif

+#ifdef HAVE_BUG_FUNCTION +# define __BUG_FUNC __func__ +#else +# define __BUG_FUNC NULL +#endif + #define BUG_ENTRY(insn, flags, ...) \ __asm__ __volatile__( \ "1: " insn "\n" \ _EMIT_BUG_ENTRY \ - : : "i" (__FILE__), "i" (__LINE__), \ + : : "i" (__FILE__), "i" (__BUG_FUNC), \ + "i" (__LINE__), \ "i" (flags), \ "i" (sizeof(struct bug_entry)), \ ##__VA_ARGS__) @@ -80,7 +99,7 @@ if (x) \ BUG(); \ } else { \ - BUG_ENTRY(PPC_TLNEI " %4, 0", 0, "r" ((__force long)(x))); \ + BUG_ENTRY(PPC_TLNEI " %5, 0", 0, "r" ((__force long)(x))); \ } \ } while (0)

@@ -90,7 +109,7 @@ if (__ret_warn_on) \ __WARN(); \ } else { \ - BUG_ENTRY(PPC_TLNEI " %4, 0", \ + BUG_ENTRY(PPC_TLNEI " %5, 0", \ BUGFLAG_WARNING | BUGFLAG_TAINT(TAINT_WARN), \ "r" (__ret_warn_on)); \ } \