[PATCH] dyndbg: Ignore additional arguments from pr_fmt

From: Philipp Hahn

Date: Fri Feb 27 2026 - 04:53:04 EST


pr_fmt can be used to add a common prefix to any output from a module:
#define pr_fmt(fmt) KBUILD_MODNAME ".%s ", __func__

But adding additional arguments breaks dynamic debug:
> error: macro "DEFINE_DYNAMIC_DEBUG_METADATA_CLS" passed 4 arguments, but takes just 3
> | pr_debug_ratelimited("%s", "Hello world!");
> | ^
> note: macro "DEFINE_DYNAMIC_DEBUG_METADATA_CLS" defined here
> | #define DEFINE_DYNAMIC_DEBUG_METADATA_CLS(name, cls, fmt) \
> |
> error: ‘DEFINE_DYNAMIC_DEBUG_METADATA_CLS’ undeclared (first use in this function)
> | DEFINE_DYNAMIC_DEBUG_METADATA_CLS(name, _DPRINTK_CLASS_DFLT, fmt)
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> note: in expansion of macro ‘DEFINE_DYNAMIC_DEBUG_METADATA’
> | DEFINE_DYNAMIC_DEBUG_METADATA(descriptor, pr_fmt(fmt)); \
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> note: in expansion of macro ‘pr_debug_ratelimited’
> | pr_debug_ratelimited("%s", "Hello world!");
> | ^~~~~~~~~~~~~~~~~~~~

Add an additional ', ...' to DEFINE_DYNAMIC_DEBUG_METADATA_CLS to slurp
any additional argument, which `pr_fmt` might add.

Signed-off-by: Philipp Hahn <phahn-oss@xxxxxx>
---
include/linux/dynamic_debug.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index 05743900a1169..0ac0df04bac00 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -167,7 +167,7 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
dump_stack(); \
}

-#define DEFINE_DYNAMIC_DEBUG_METADATA_CLS(name, cls, fmt) \
+#define DEFINE_DYNAMIC_DEBUG_METADATA_CLS(name, cls, fmt, ...) \
static struct _ddebug __aligned(8) \
__section("__dyndbg") name = { \
.modname = KBUILD_MODNAME, \
--
2.43.0


--CFwBZZ+b2rGOhDlc--