[tip: objtool/core] objtool/klp: Remove trailing '_' in demangle_name()

[tip-bot2 for Song Liu]

The following commit has been merged into the objtool/core branch of tip:

Commit-ID:     a3f28d2072452edb377eaad01375445dbace6771
Gitweb:        https://git.kernel.org/tip/a3f28d2072452edb377eaad01375445dbace6771
Author:        Song Liu <song@xxxxxxxxxx>
AuthorDate:    Thu, 05 Mar 2026 15:15:26 -08:00
Committer:     Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
CommitterDate: Fri, 06 Mar 2026 08:08:30 -08:00

objtool/klp: Remove trailing '_' in demangle_name()

With CONFIG_LTO_CLANG_THIN, it is possible to have nested __UNIQUE_ID_,
such as:

  __UNIQUE_ID_addressable___UNIQUE_ID_pci_invalid_bar_694_695

To remove both trailing numbers, also remove trailing '_'.

Also add comments to demangle_name().

Signed-off-by: Song Liu <song@xxxxxxxxxx>
Link: https://patch.msgid.link/20260305231531.3847295-3-song@xxxxxxxxxx
Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
---
 tools/objtool/elf.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index a634b22..fe6e66d 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -441,6 +441,19 @@ static int read_sections(struct elf *elf)
 	return 0;
 }
 
+/*
+ * Remove number suffix of a symbol.
+ *
+ * Specifically, remove trailing numbers for "__UNIQUE_ID_" symbols and
+ * symbols with '.'.
+ *
+ * With CONFIG_LTO_CLANG_THIN, it is possible to have nested __UNIQUE_ID_,
+ * such as
+ *
+ *   __UNIQUE_ID_addressable___UNIQUE_ID_pci_invalid_bar_694_695
+ *
+ * to remove both trailing numbers, also remove trailing '_'.
+ */
 static const char *demangle_name(struct symbol *sym)
 {
 	char *str;
@@ -463,7 +476,7 @@ static const char *demangle_name(struct symbol *sym)
 	for (int i = strlen(str) - 1; i >= 0; i--) {
 		char c = str[i];
 
-		if (!isdigit(c) && c != '.') {
+		if (!isdigit(c) && c != '.' && c != '_') {
 			str[i + 1] = '\0';
 			break;
 		}