Add support for suppressing warning backtraces #828
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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. Since the new functionality results in an image size increase of about 1% if CONFIG_KUNIT is enabled, provide configuration option KUNIT_SUPPRESS_BACKTRACE to be able to disable the new functionality. This option is by default enabled since almost all systems with CONFIG_KUNIT enabled will want to benefit from it. 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> Tested-by: Linux Kernel Functional Testing <lkft@linaro.org> Acked-by: Dan Carpenter <dan.carpenter@linaro.org> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
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. Acked-by: Dan Carpenter <dan.carpenter@linaro.org> Reviewed-by: Kees Cook <keescook@chromium.org> Tested-by: Linux Kernel Functional Testing <lkft@linaro.org> Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
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. Tested-by: Linux Kernel Functional Testing <lkft@linaro.org> Acked-by: Dan Carpenter <dan.carpenter@linaro.org> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
Document API functions for suppressing warning backtraces. Tested-by: Linux Kernel Functional Testing <lkft@linaro.org> Acked-by: Dan Carpenter <dan.carpenter@linaro.org> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
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 and distraction from real problems. Tested-by: Linux Kernel Functional Testing <lkft@linaro.org> Acked-by: Dan Carpenter <dan.carpenter@linaro.org> Acked-by: Maíra Canal <mcanal@igalia.com> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: David Airlie <airlied@gmail.com> Cc: Daniel Vetter <daniel@ffwll.ch> Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
dev_addr_lists_test generates lock warning noise at the end of tests if lock debugging is enabled. There are two sets of warnings. WARNING: CPU: 0 PID: 689 at kernel/locking/mutex.c:923 __mutex_unlock_slowpath.constprop.0+0x13c/0x368 DEBUG_LOCKS_WARN_ON(__owner_task(owner) != __get_current()) WARNING: kunit_try_catch/1336 still has locks held! KUnit test cleanup is not guaranteed to run in the same thread as the test itself. For this test, this means that rtnl_lock() and rtnl_unlock() may be called from different threads. This triggers the warnings. Suppress the warnings because they are irrelevant for the test and just confusing and distracting. The first warning can be suppressed by using START_SUPPRESSED_WARNING() and END_SUPPRESSED_WARNING() around the call to rtnl_unlock(). To suppress the second warning, it is necessary to set debug_locks_silent while the rtnl lock is held. Tested-by: Linux Kernel Functional Testing <lkft@linaro.org> Cc: David Gow <davidgow@google.com> Cc: Jakub Kicinski <kuba@kernel.org> Cc: Eric Dumazet <edumazet@google.com> Acked-by: Dan Carpenter <dan.carpenter@linaro.org> Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
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_SUPPRESS_BACKTRACE 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). Tested-by: Linux Kernel Functional Testing <lkft@linaro.org> Acked-by: Dan Carpenter <dan.carpenter@linaro.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
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_SUPPRESS_BACKTRACE 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). Tested-by: Linux Kernel Functional Testing <lkft@linaro.org> Acked-by: Dan Carpenter <dan.carpenter@linaro.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
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_SUPPRESS_BACKTRACE 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). Tested-by: Linux Kernel Functional Testing <lkft@linaro.org> Acked-by: Dan Carpenter <dan.carpenter@linaro.org> Cc: Huacai Chen <chenhuacai@kernel.org> Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
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_SUPPRESS_BACKTRACE 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). While at it, declare assembler parameters as constants where possible. Refine .blockz instructions to calculate the necessary padding instead of using fixed values. Tested-by: Linux Kernel Functional Testing <lkft@linaro.org> Acked-by: Dan Carpenter <dan.carpenter@linaro.org> Acked-by: Helge Deller <deller@gmx.de> Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
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_SUPPRESS_BACKTRACE 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). Tested-by: Linux Kernel Functional Testing <lkft@linaro.org> Acked-by: Dan Carpenter <dan.carpenter@linaro.org> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
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_SUPPRESS_BACKTRACE 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). Tested-by: Linux Kernel Functional Testing <lkft@linaro.org> Acked-by: Dan Carpenter <dan.carpenter@linaro.org> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Rich Felker <dalias@libc.org> Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de> Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
Declaring the defines needed for suppressing warning inside '#ifdef CONFIG_DEBUG_BUGVERBOSE' results in a kerneldoc warning. .../bug.h:29: warning: expecting prototype for _EMIT_BUG_ENTRY(). Prototype was for HAVE_BUG_FUNCTION() instead Move the defines above the kerneldoc entry for _EMIT_BUG_ENTRY to make kerneldoc happy. Reported-by: Simon Horman <horms@kernel.org> Cc: Simon Horman <horms@kernel.org> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Rich Felker <dalias@libc.org> Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de> Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
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_SUPPRESS_BACKTRACE 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). To simplify the implementation, unify the __BUG_ENTRY_ADDR and __BUG_ENTRY_FILE macros into a single macro named __BUG_REL() which takes the address, file, or function reference as parameter. Tested-by: Linux Kernel Functional Testing <lkft@linaro.org> Acked-by: Dan Carpenter <dan.carpenter@linaro.org> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Albert Ou <aou@eecs.berkeley.edu> Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
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_SUPPRESS_BACKTRACE 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). Tested-by: Linux Kernel Functional Testing <lkft@linaro.org> Acked-by: Dan Carpenter <dan.carpenter@linaro.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
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At least one diff in series https://patchwork.kernel.org/project/linux-riscv/list/?series=841086 irrelevant now. Closing PR. |
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Pull request for series with
subject: Add support for suppressing warning backtraces
version: 3
url: https://patchwork.kernel.org/project/linux-riscv/list/?series=841086