[PATCH v2] modpost: Ignore Clang LTO suffixes in symbol matching

[xur]

From: Rong Xu <xur@xxxxxxxxxx>

When building the kernel with Clang ThinLTO enabled, the compiler
can mangle static variable names by appending suffixes such as
".llvm.<hash>" to prevent naming collisions across translation units.

This name mangling breaks the section mismatch whitelisting in modpost.
modpost relies on glob patterns (e.g., "*_ops" or "*_probe") to identify
safe references between permanent data and initialization code. Because
the LTO suffix modifies the end of the symbol name, legitimately
whitelisted structures fail the match, resulting in false positive
warnings.

For example, a static pernet_operations struct triggers the following:

  WARNING: modpost: vmlinux: section mismatch in reference: \
  ping_v4_net_ops.llvm.5641696707737373282 (section: .data) -> \
  ping_v4_proc_init_net (section: .init.text)

Fix this by ignoring "*_ops.llvm.*" in "from" symbol names (the same
as "*_ops").

Reported-by: kernel test robot <lkp@xxxxxxxxx>
Closes: https://lore.kernel.org/oe-kbuild-all/202606111233.kM8oo8Df-lkp@xxxxxxxxx/
Signed-off-by: Rong Xu <xur@xxxxxxxxxx>
---
 scripts/mod/modpost.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index d592548cbd60..a7b72a81d248 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -969,7 +969,7 @@ static int secref_whitelist(const char *fromsec, const char *fromsym,
 	/* symbols in data sections that may refer to any init/exit sections */
 	if (match(fromsec, PATTERNS(DATA_SECTIONS)) &&
 	    match(tosec, PATTERNS(ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS)) &&
-	    match(fromsym, PATTERNS("*_ops", "*_console")))
+	    match(fromsym, PATTERNS("*_ops", "*_ops.llvm.*", "*_console")))
 		return 0;
 
 	/* Check for pattern 3 */

base-commit: e771677c937da5808f7b6c1f0e4a97ec1a84f8a8
-- 
2.55.0.rc0.738.g0c8ab3ebcc-goog