linux-kernel - [PATCH] objtool: Fix false "ignoring unreachables" warning

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Message-ID: <5eb28eeb6a724b7d945a961cfdcf8d41e6edf3dc.1744238814.git.jpoimboe@kernel.org>
Date: Wed,  9 Apr 2025 15:49:36 -0700
From: Josh Poimboeuf <jpoimboe@...nel.org>
To: x86@...nel.org
Cc: linux-kernel@...r.kernel.org,
	Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...nel.org>,
	kernel test robot <lkp@...el.com>
Subject: [PATCH] objtool: Fix false "ignoring unreachables" warning

There's no need to try to automatically disable unreachable warnings if
they've already been manually disabled due to CONFIG_KCOV quirks.

This avoids a spurious warning with a KCOV kernel:

  fs/smb/client/cifs_unicode.o: warning: objtool: cifsConvertToUTF16.part.0+0xce5: ignoring unreachables due to jump table quirk

Reported-by: kernel test robot <lkp@...el.com>
Closes: https://lore.kernel.org/r/202504090910.QkvTAR36-lkp@intel.com/
Signed-off-by: Josh Poimboeuf <jpoimboe@...nel.org>
---
 tools/objtool/arch/x86/special.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/objtool/arch/x86/special.c b/tools/objtool/arch/x86/special.c
index 403e587676f1..06ca4a2659a4 100644
--- a/tools/objtool/arch/x86/special.c
+++ b/tools/objtool/arch/x86/special.c
@@ -126,7 +126,7 @@ struct reloc *arch_find_switch_table(struct objtool_file *file,
 	 * indicates a rare GCC quirk/bug which can leave dead
 	 * code behind.
 	 */
-	if (reloc_type(text_reloc) == R_X86_64_PC32) {
+	if (!file->ignore_unreachables && reloc_type(text_reloc) == R_X86_64_PC32) {
 		WARN_INSN(insn, "ignoring unreachables due to jump table quirk");
 		file->ignore_unreachables = true;
 	}
-- 
2.49.0