[GIT pull] objtool/urgent for 5.7-rc5

[Thomas Gleixner]

Linus,

please pull the latest objtool/urgent branch from:

   git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git objtool-urgent-2020-05-10

up to:  1119d265bc20: objtool: Fix infinite loop in find_jump_table()


A single fix for objtool to prevent an infinite loop in the jump table
search which can be triggered when building the kernel with
-ffunction-sections.

Thanks,

	tglx

------------------>
Josh Poimboeuf (1):
      objtool: Fix infinite loop in find_jump_table()


 tools/objtool/check.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 4b170fd08a28..0e8f9a32e4d1 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -72,6 +72,17 @@ static struct instruction *next_insn_same_func(struct objtool_file *file,
 	return find_insn(file, func->cfunc->sec, func->cfunc->offset);
 }
 
+static struct instruction *prev_insn_same_sym(struct objtool_file *file,
+					       struct instruction *insn)
+{
+	struct instruction *prev = list_prev_entry(insn, list);
+
+	if (&prev->list != &file->insn_list && prev->func == insn->func)
+		return prev;
+
+	return NULL;
+}
+
 #define func_for_each_insn(file, func, insn)				\
 	for (insn = find_insn(file, func->sec, func->offset);		\
 	     insn;							\
@@ -1050,8 +1061,8 @@ static struct rela *find_jump_table(struct objtool_file *file,
 	 * it.
 	 */
 	for (;
-	     &insn->list != &file->insn_list && insn->func && insn->func->pfunc == func;
-	     insn = insn->first_jump_src ?: list_prev_entry(insn, list)) {
+	     insn && insn->func && insn->func->pfunc == func;
+	     insn = insn->first_jump_src ?: prev_insn_same_sym(file, insn)) {
 
 		if (insn != orig_insn && insn->type == INSN_JUMP_DYNAMIC)
 			break;