From: Josh Poimboeuf <jpoimboe@redhat.com>
Date: Wed, 1 Apr 2020 18:23:29 +0000 (-0500)
Subject: objtool: Make BP scratch register warning more robust
X-Git-Tag: v5.7-rc2~3^2~7
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=b296695298d8632d8b703ac25fe70be34a07c0d9;p=thirdparty%2Fkernel%2Flinux.git

objtool: Make BP scratch register warning more robust

If func is NULL, a seg fault can result.

This is a theoretical issue which was found by Coverity, ID: 1492002
("Dereference after null check").

Fixes: c705cecc8431 ("objtool: Track original function across branches")
Reported-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/afc628693a37acd287e843bcc5c0430263d93c74.1585761021.git.jpoimboe@redhat.com
---

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index cb2d299664e72..4b170fd08a28b 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -2005,8 +2005,8 @@ static int validate_return(struct symbol *func, struct instruction *insn, struct
 	}
 
 	if (state->bp_scratch) {
-		WARN("%s uses BP as a scratch register",
-		     func->name);
+		WARN_FUNC("BP used as a scratch register",
+			  insn->sec, insn->offset);
 		return 1;
 	}