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: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Josh 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: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Josh Poimboeuf 2016-03-09 00:07:01 -06:00 committed by Ingo Molnar
parent 042ba73fe7
commit 1bcb58a099
1 changed files with 25 additions and 23 deletions

View File

@ -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++;
}