objtool: Fix another switch table detection issue

Continue the switch table detection whack-a-mole. Add a check to distinguish KASAN data reads from switch data reads. The switch jump tables in .rodata have relocations associated with them. This fixes the following warning: crypto/asymmetric_keys/x509_cert_parser.o: warning: objtool: x509_note_pkey_algo()+0xa4: sibling call from callable instruction with modified stack frame Reported-by: Arnd Bergmann <[email protected]> Signed-off-by: Josh Poimboeuf <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> Tested-by: Arnd Bergmann <[email protected]> Cc: Peter Zijlstra <[email protected]> Link: https://lkml.kernel.org/r/d7c8853022ad47d158cb81e953a40469fc08a95e.1519784382.git.jpoimboe@redhat.com
ambv · Feb 28, 2018 · 1402fd8 · 1402fd8
1 parent 71c208d
commit 1402fd8
Showing 1 changed file with 5 additions and 1 deletion.
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
@@ -925,7 +925,11 @@ static struct rela *find_switch_table(struct objtool_file *file,
 		if (find_symbol_containing(file->rodata, text_rela->addend))
 			continue;
 
-		return find_rela_by_dest(file->rodata, text_rela->addend);
+		rodata_rela = find_rela_by_dest(file->rodata, text_rela->addend);
+		if (!rodata_rela)
+			continue;
+
+		return rodata_rela;
 	}
 
 	return NULL;