linux-kernel - [tip: objtool/urgent] Revert "objtool: Increase per-function WARN

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Message-ID: <174349171954.14745.12146555759231129514.tip-bot2@tip-bot2>
Date: Tue, 01 Apr 2025 07:15:19 -0000
From: "tip-bot2 for Josh Poimboeuf" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Ingo Molnar <mingo@...nel.org>, Josh Poimboeuf <jpoimboe@...nel.org>,
 Linus Torvalds <torvalds@...ux-foundation.org>, x86@...nel.org,
 linux-kernel@...r.kernel.org
Subject: [tip: objtool/urgent] Revert "objtool: Increase per-function
 WARN_FUNC() rate limit"

The following commit has been merged into the objtool/urgent branch of tip:

Commit-ID:     c5610071a69d1c94c70e681874298b4fc6942098
Gitweb:        https://git.kernel.org/tip/c5610071a69d1c94c70e681874298b4fc6942098
Author:        Josh Poimboeuf <jpoimboe@...nel.org>
AuthorDate:    Mon, 31 Mar 2025 21:26:39 -07:00
Committer:     Ingo Molnar <mingo@...nel.org>
CommitterDate: Tue, 01 Apr 2025 09:07:13 +02:00

Revert "objtool: Increase per-function WARN_FUNC() rate limit"

This reverts commit 0a7fb6f07e3ad497d31ae9a2082d2cacab43d54a.

The "skipping duplicate warnings" warning is technically not an actual
warning, which can cause confusion.  This feature isn't all that useful
anyway.  It's exceedingly rare for a function to have more than one
unrelated warning.

Suggested-by: Ingo Molnar <mingo@...nel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@...nel.org>
Signed-off-by: Ingo Molnar <mingo@...nel.org>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Link: https://lore.kernel.org/r/e5abe5e858acf1a9207a5dfa0f37d17ac9dca872.1743481539.git.jpoimboe@kernel.org
---
 tools/objtool/check.c                |  4 ++--
 tools/objtool/include/objtool/elf.h  |  2 +-
 tools/objtool/include/objtool/warn.h | 14 +++-----------
 3 files changed, 6 insertions(+), 14 deletions(-)

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index bd0c78b..c8b3c8e 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -3545,7 +3545,7 @@ static int validate_branch(struct objtool_file *file, struct symbol *func,
 
 			WARN("%s() falls through to next function %s()",
 			     func->name, insn_func(insn)->name);
-			func->warnings++;
+			func->warned = 1;
 
 			return 1;
 		}
@@ -4576,7 +4576,7 @@ static void disas_warned_funcs(struct objtool_file *file)
 	char *funcs = NULL, *tmp;
 
 	for_each_sym(file, sym) {
-		if (sym->warnings) {
+		if (sym->warned) {
 			if (!funcs) {
 				funcs = malloc(strlen(sym->name) + 1);
 				if (!funcs) {
diff --git a/tools/objtool/include/objtool/elf.h b/tools/objtool/include/objtool/elf.h
index eba0439..c7c4e87 100644
--- a/tools/objtool/include/objtool/elf.h
+++ b/tools/objtool/include/objtool/elf.h
@@ -65,11 +65,11 @@ struct symbol {
 	u8 return_thunk      : 1;
 	u8 fentry            : 1;
 	u8 profiling_func    : 1;
+	u8 warned	     : 1;
 	u8 embedded_insn     : 1;
 	u8 local_label       : 1;
 	u8 frame_pointer     : 1;
 	u8 ignore	     : 1;
-	u8 warnings	     : 2;
 	struct list_head pv_target;
 	struct reloc *relocs;
 };
diff --git a/tools/objtool/include/objtool/warn.h b/tools/objtool/include/objtool/warn.h
index b29ac14..e3ad9b2 100644
--- a/tools/objtool/include/objtool/warn.h
+++ b/tools/objtool/include/objtool/warn.h
@@ -57,22 +57,14 @@ static inline char *offstr(struct section *sec, unsigned long offset)
 	free(_str);					\
 })
 
-#define WARN_LIMIT 2
-
 #define WARN_INSN(insn, format, ...)					\
 ({									\
 	struct instruction *_insn = (insn);				\
-	BUILD_BUG_ON(WARN_LIMIT > 2);					\
-	if (!_insn->sym || _insn->sym->warnings < WARN_LIMIT) {		\
+	if (!_insn->sym || !_insn->sym->warned)				\
 		WARN_FUNC(format, _insn->sec, _insn->offset,		\
 			  ##__VA_ARGS__);				\
-		if (_insn->sym)						\
-			_insn->sym->warnings++;				\
-	} else if (_insn->sym && _insn->sym->warnings == WARN_LIMIT) {	\
-		WARN_FUNC("skipping duplicate warning(s)",		\
-			  _insn->sec, _insn->offset);			\
-		_insn->sym->warnings++;					\
-	}								\
+	if (_insn->sym)							\
+		_insn->sym->warned = 1;					\
 })
 
 #define BT_INSN(insn, format, ...)				\