Le 04/05/2026 à 3:41 PM, Albert Esteve a écrit :
From: Guenter Roeck <[email protected]>
Document API functions for suppressing warning backtraces.
Tested-by: Linux Kernel Functional Testing <[email protected]>
Acked-by: Dan Carpenter <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Signed-off-by: Guenter Roeck <[email protected]>
Reviewed-by: David Gow <[email protected]>
Signed-off-by: Alessandro Carminati <[email protected]>
Reviewed-by: David Gow <[email protected]>
Signed-off-by: Albert Esteve <[email protected]>
---
This is great, thanks!
Reviewed-by: David Gow <[email protected]>
Cheers,
-- David
Documentation/dev-tools/kunit/usage.rst | 63 ++++++++++++++++++++++++++++++++-
1 file changed, 62 insertions(+), 1 deletion(-)
diff --git a/Documentation/dev-tools/kunit/usage.rst
b/Documentation/dev-tools/kunit/usage.rst
index ebd06f5ea4550..25724f7e72969 100644
--- a/Documentation/dev-tools/kunit/usage.rst
+++ b/Documentation/dev-tools/kunit/usage.rst
@@ -157,6 +157,67 @@ 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 a 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.
+
+Backtraces can be suppressed with **task-scoped suppression**: while
+suppression is active on the current task, the backtrace and stack dump from
+``WARN*()``, ``WARN_ON*()``, and related macros on that task are suppressed.
+Three API forms are available, in order of convenience.
+
+- Scoped suppression is the simplest form. Wrap the code that triggers
+ warnings in a ``kunit_warning_suppress()`` block:
+
+.. code-block:: c
+
+ static void some_test(struct kunit *test)
+ {
+ kunit_warning_suppress(test) {
+ trigger_backtrace();
+ KUNIT_EXPECT_SUPPRESSED_WARNING_COUNT(test, 1);
+ }
+ }
+
+.. note::
+ The warning count must be checked inside the block; the suppression handle
+ is not accessible after the block exits.
+
+- Manual macros are useful when the suppressed region is large enough that
+ extra indentation is undesirable, or when the warning count needs to be
+ checked after suppression ends. ``KUNIT_START_SUPPRESSED_WARNING()`` must
+ appear before ``KUNIT_END_SUPPRESSED_WARNING()`` in the same scope.
+ Limited to one pair per scope.
+
+.. code-block:: c
+
+ static void some_test(struct kunit *test)
+ {
+ KUNIT_START_SUPPRESSED_WARNING(test);
+ trigger_backtrace();
+ KUNIT_END_SUPPRESSED_WARNING(test);
+
+ KUNIT_EXPECT_SUPPRESSED_WARNING_COUNT(test, 1);
+ }
+
+- Direct functions return an explicit handle pointer. Use them when the handle
+ needs to be retained or passed across helper functions:
+
+.. code-block:: c
+
+ static void some_test(struct kunit *test)
+ {
+ struct kunit_suppressed_warning *w;
+
+ w = kunit_start_suppress_warning(test);
+ trigger_backtrace();
+ kunit_end_suppress_warning(test, w);
+
+ KUNIT_EXPECT_EQ(test, kunit_suppressed_warning_count(w), 1);
+ }
Test Suites
~~~~~~~~~~~
@@ -1211,4 +1272,4 @@ 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
+ }
