When GCC adds NOP padding between functions, those NOPs aren't
associated with a function symbol, which breaks objtool's detection of a
function falling through to another function. Instead it shows
confusing errors like:
drivers/mtd/chips/cfi_util.o: warning: objtool: cfi_qry_mode_on()+0x8b:
return with modified stack frame
drivers/mtd/chips/cfi_util.o: warning: objtool: cfi_qry_mode_on()+0x0: stack
state mismatch: cfa1=-4-32 cfa2=7+8
drivers/mtd/chips/cfi_cmdset_0002.o: warning: objtool:
fixup_use_fwh_lock()+0x8: unknown stack-related register move
drivers/mtd/chips/cfi_cmdset_0002.o: warning: objtool:
fixup_use_fwh_lock()+0x0: stack state mismatch: cfa1=6+16 cfa2=7+8
drivers/mtd/chips/cfi_cmdset_0002.o: warning: objtool: do_otp_write()+0xa:
unsupported stack pointer realignment
drivers/mtd/chips/cfi_cmdset_0002.o: warning: objtool: do_otp_write()+0x0:
stack state mismatch: cfa1=-4-40 cfa2=7+8
Reported-by: kbuild test robot
Signed-off-by: Josh Poimboeuf
---
tools/objtool/check.c | 14 +++---
1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 17375925e7aa..3dffeb944523 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -1536,15 +1536,15 @@ static int validate_branch(struct objtool_file *file,
struct instruction *first,
while (1) {
next_insn = next_insn_same_sec(file, insn);
- if (file->c_file && insn->func) {
- if (func && func != insn->func) {
- WARN("%s() falls through to next function %s()",
-func->name, insn->func->name);
- return 1;
- }
+
+ if (file->c_file && func && insn->func && func != insn->func) {
+ WARN("%s() falls through to next function %s()",
+func->name, insn->func->name);
+ return 1;
}
- func = insn->func;
+ if (insn->func)
+ func = insn->func;
if (func && insn->ignore) {
WARN_FUNC("BUG: why am I validating an ignored
function?",
--
2.13.3
