Commit 1bcb58a0 authored by Josh Poimboeuf's avatar Josh Poimboeuf Committed by Ingo Molnar
Browse files

objtool: Only print one warning per function 



When objtool discovers an issue, it's very common for it to flood the
terminal with a lot of duplicate warnings.  For example:

  warning: objtool: rtlwifi_rate_mapping()+0x2e7: frame pointer state mismatch
  warning: objtool: rtlwifi_rate_mapping()+0x2f3: frame pointer state mismatch
  warning: objtool: rtlwifi_rate_mapping()+0x2ff: frame pointer state mismatch
  warning: objtool: rtlwifi_rate_mapping()+0x30b: frame pointer state mismatch
  ...

The first warning is usually all you need.  Change it to only warn once
per function.

Suggested-by: default avatarIngo Molnar <mingo@kernel.org>
Signed-off-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Bernd Petrovitsch <bernd@petrovitsch.priv.at>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Chris J Arges <chris.j.arges@canonical.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Pedro Alves <palves@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/c47f3ca38aa01e2a9b6601f9e38efd414c3f3c18.1457502970.git.jpoimboe@redhat.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 042ba73f

tools/objtool/builtin-check.c

+25 −23
Original line number Diff line number Diff line
@@ -800,7 +800,7 @@ static int validate_branch(struct objtool_file *file, 
	struct instruction *insn;

	struct section *sec;

	unsigned char state;

	int ret, warnings = 0;

	int ret;



	insn = first;

	sec = insn->sec;
@@ -809,7 +809,7 @@ static int validate_branch(struct objtool_file *file, 
	if (insn->alt_group && list_empty(&insn->alts)) {

		WARN_FUNC("don't know how to handle branch to middle of alternative instruction group",

			  sec, insn->offset);

		warnings++;

		return 1;

	}



	while (1) {
@@ -817,10 +817,10 @@ static int validate_branch(struct objtool_file *file, 
			if (frame_state(insn->state) != frame_state(state)) {

				WARN_FUNC("frame pointer state mismatch",

					  sec, insn->offset);

				warnings++;

				return 1;

			}



			return warnings;

			return 0;

		}



		/*
@@ -828,14 +828,15 @@ static int validate_branch(struct objtool_file *file, 
		 * the next function.

		 */

		if (is_fentry_call(insn) && (state & STATE_FENTRY))

			return warnings;

			return 0;



		insn->visited = true;

		insn->state = state;



		list_for_each_entry(alt, &insn->alts, list) {

			ret = validate_branch(file, alt->insn, state);

			warnings += ret;

			if (ret)

				return 1;

		}



		switch (insn->type) {
@@ -845,7 +846,7 @@ static int validate_branch(struct objtool_file *file, 
				if (state & STATE_FP_SAVED) {

					WARN_FUNC("duplicate frame pointer save",

						  sec, insn->offset);

					warnings++;

					return 1;

				}

				state |= STATE_FP_SAVED;

			}
@@ -856,7 +857,7 @@ static int validate_branch(struct objtool_file *file, 
				if (state & STATE_FP_SETUP) {

					WARN_FUNC("duplicate frame pointer setup",

						  sec, insn->offset);

					warnings++;

					return 1;

				}

				state |= STATE_FP_SETUP;

			}
@@ -875,9 +876,9 @@ static int validate_branch(struct objtool_file *file, 
			if (!nofp && has_modified_stack_frame(insn)) {

				WARN_FUNC("return without frame pointer restore",

					  sec, insn->offset);

				warnings++;

				return 1;

			}

			return warnings;

			return 0;



		case INSN_CALL:

			if (is_fentry_call(insn)) {
@@ -887,16 +888,16 @@ static int validate_branch(struct objtool_file *file, 


			ret = dead_end_function(file, insn->call_dest);

			if (ret == 1)

				return warnings;

				return 0;

			if (ret == -1)

				warnings++;

				return 1;



			/* fallthrough */

		case INSN_CALL_DYNAMIC:

			if (!nofp && !has_valid_stack_frame(insn)) {

				WARN_FUNC("call without frame pointer save/setup",

					  sec, insn->offset);

				warnings++;

				return 1;

			}

			break;
@@ -905,15 +906,16 @@ static int validate_branch(struct objtool_file *file, 
			if (insn->jump_dest) {

				ret = validate_branch(file, insn->jump_dest,

						      state);

				warnings += ret;

				if (ret)

					return 1;

			} else if (has_modified_stack_frame(insn)) {

				WARN_FUNC("sibling call from callable instruction with changed frame pointer",

					  sec, insn->offset);

				warnings++;

				return 1;

			} /* else it's a sibling call */



			if (insn->type == INSN_JUMP_UNCONDITIONAL)

				return warnings;

				return 0;



			break;
@@ -922,13 +924,13 @@ static int validate_branch(struct objtool_file *file, 
			    has_modified_stack_frame(insn)) {

				WARN_FUNC("sibling call from callable instruction with changed frame pointer",

					  sec, insn->offset);

				warnings++;

				return 1;

			}



			return warnings;

			return 0;



		case INSN_BUG:

			return warnings;

			return 0;



		default:

			break;
@@ -937,12 +939,11 @@ static int validate_branch(struct objtool_file *file, 
		insn = next_insn_same_sec(file, insn);

		if (!insn) {

			WARN("%s: unexpected end of section", sec->name);

			warnings++;

			return warnings;

			return 1;

		}

	}



	return warnings;

	return 0;

}



static bool is_gcov_insn(struct instruction *insn)
@@ -1055,7 +1056,8 @@ static int validate_functions(struct objtool_file *file) 
				if (insn->visited)

					continue;



				if (!ignore_unreachable_insn(func, insn)) {

				if (!ignore_unreachable_insn(func, insn) &&

				    !warnings) {

					WARN_FUNC("function has unreachable instruction", insn->sec, insn->offset);

					warnings++;

				}

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