[PATCH bpf-next] lib/Kconfig.debug: add prompt for kernel module BTF

With DEBUG_INFO_BTF_MODULES enabled, a BTF mismatch between vmlinux
and a separately-built module prevents the module from loading, even
if the ABI is otherwise compatible and the module would otherwise load
without issues. Currently this can be avoided only by disabling BTF
entirely; disabling just module BTF would be sufficient but is not
possible with the current Kconfig.

Add a prompt for DEBUG_INFO_BTF_MODULES to allow it to be disabled
independently.

Signed-off-by: Connor O'Brien <redacted>
---
 lib/Kconfig.debug | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 1555da672275..a6bbd4bb2bde 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug

@@ -334,7 +334,7 @@ config PAHOLE_HAS_BTF_TAG
 	  these attributes, so make the config depend on CC_IS_CLANG.
 
 config DEBUG_INFO_BTF_MODULES
-	def_bool y
+	bool "Generate BTF typeinfo for modules"
 	depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
 	help
 	  Generate compact split BTF type information for kernel modules.

-- 
2.35.0.263.gb82422642f-goog

On 2/8/22 9:21 PM, Connor O'Brien wrote:

With DEBUG_INFO_BTF_MODULES enabled, a BTF mismatch between vmlinux
and a separately-built module prevents the module from loading, even
if the ABI is otherwise compatible and the module would otherwise load
without issues. Currently this can be avoided only by disabling BTF
entirely; disabling just module BTF would be sufficient but is not
possible with the current Kconfig.

Add a prompt for DEBUG_INFO_BTF_MODULES to allow it to be disabled
independently.

Signed-off-by: Connor O'Brien <redacted>

Acked-by: Yonghong Song <redacted>