[tip: objtool/core] objtool/klp: Fix cloning of zero-length section symbols

[tip-bot2 for Josh Poimboeuf]

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

Commit-ID:     98377f3ba7c02d6eb34e203c9f9823bc62b0d231
Gitweb:        https://git.kernel.org/tip/98377f3ba7c02d6eb34e203c9f9823bc62b0d231
Author:        Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
AuthorDate:    Thu, 09 Apr 2026 18:35:01 -07:00
Committer:     Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
CommitterDate: Mon, 04 May 2026 21:16:00 -07:00

objtool/klp: Fix cloning of zero-length section symbols

Fix NULL dereference when cloning a symbol from an empty section.
sec->data is only populated for sections with non-zero size.

Fixes: dd590d4d57eb ("objtool/klp: Introduce klp diff subcommand for diffing object files")
Acked-by: Song Liu <song@xxxxxxxxxx>
Reviewed-by: Miroslav Benes <mbenes@xxxxxxx>
Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
---
 tools/objtool/klp-diff.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/objtool/klp-diff.c b/tools/objtool/klp-diff.c
index a226e99..17a6146 100644
--- a/tools/objtool/klp-diff.c
+++ b/tools/objtool/klp-diff.c
@@ -681,7 +681,7 @@ static struct symbol *__clone_symbol(struct elf *elf, struct symbol *patched_sym
 			size_t size;
 
 			/* bss doesn't have data */
-			if (patched_sym->sec->data->d_buf)
+			if (patched_sym->sec->data && patched_sym->sec->data->d_buf)
 				data = patched_sym->sec->data->d_buf + patched_sym->offset;
 
 			if (is_sec_sym(patched_sym))