From: Josh Poimboeuf Date: Wed, 29 Oct 2025 19:54:08 +0000 (-0700) Subject: objtool: Fix skip_alt_group() for non-alternative STAC/CLAC X-Git-Tag: v6.18-rc4~6^2 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=c44b4b9eeb71f5b0b617abf6fd66d1ef0aab6200;p=thirdparty%2Fkernel%2Flinux.git objtool: Fix skip_alt_group() for non-alternative STAC/CLAC If an insn->alt points to a STAC/CLAC instruction, skip_alt_group() assumes it's part of an alternative ("alt group") as opposed to some other kind of "alt" such as an exception fixup. While that assumption may hold true in the current code base, Linus has an out-of-tree patch which breaks that assumption by replacing the STAC/CLAC alternatives with raw STAC/CLAC instructions. Make skip_alt_group() more robust by making sure it's actually an alt group before continuing. Reported-by: Linus Torvalds Fixes: 2d12c6fb7875 ("objtool: Remove ANNOTATE_IGNORE_ALTERNATIVE from CLAC/STAC") Closes: https://lore.kernel.org/CAHk-=wi6goUT36sR8GE47_P-aVrd5g38=VTRHpktWARbyE-0ow@mail.gmail.com Signed-off-by: Josh Poimboeuf Signed-off-by: Ingo Molnar Tested-by: Linus Torvalds Link: https://patch.msgid.link/3d22415f7b8e06a64e0873b21f48389290eeaa49.1761767616.git.jpoimboe@kernel.org --- diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 620854fdaaf6..9004fbc06769 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -3516,8 +3516,11 @@ static bool skip_alt_group(struct instruction *insn) { struct instruction *alt_insn = insn->alts ? insn->alts->insn : NULL; + if (!insn->alt_group) + return false; + /* ANNOTATE_IGNORE_ALTERNATIVE */ - if (insn->alt_group && insn->alt_group->ignore) + if (insn->alt_group->ignore) return true; /*