From: Julien Thierry <[email protected]>

[ Upstream commit 7170cf47d16f1ba29eca07fd818870b7af0a93a5 ]

The .alternatives section can contain entries with no original
instructions. Objtool will currently crash when handling such an entry.

Just skip that entry, but still give a warning to discourage useless
entries.

Signed-off-by: Julien Thierry <[email protected]>
Acked-by: Peter Zijlstra (Intel) <[email protected]>
Reviewed-by: Miroslav Benes <[email protected]>
Signed-off-by: Josh Poimboeuf <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
---
 tools/objtool/check.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index fcc6cd404f56..48b234d8f251 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -865,6 +865,12 @@ static int add_special_section_alts(struct objtool_file 
*file)
                }
 
                if (special_alt->group) {
+                       if (!special_alt->orig_len) {
+                               WARN_FUNC("empty alternative entry",
+                                         orig_insn->sec, orig_insn->offset);
+                               continue;
+                       }
+
                        ret = handle_group_alt(file, special_alt, orig_insn,
                                               &new_insn);
                        if (ret)
-- 
2.25.1



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