From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 48AA233120E; Tue, 31 Mar 2026 16:49:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774975754; cv=none; b=uQP18EkGg6tKzyXtShy7R9OU7igvirLRs2iay1xWEB3m68kx04ZejxUo/Pwo0I5JCo7hdpqip6jQVBnLZsynu07dgp96VtsoC2U0IvY34ugf3qtPfp31a/q4upKvJ06wNEoXep2NZ4u9R2+Mr95IZbeLwqnSdlX8cLNh3TMRD3w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774975754; c=relaxed/simple; bh=bQYArPzY/siTpP7U3fgPGvC1BttN5s1ntOkESjt0SEk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=TaZKnQY6GuyCYHOqvTbFs22h6K0F7fvDxnBPLkisxdz+EvjCNXsbIhy1fSzYzmnKadMlfoJolkOWx2n+siVhNmUWRj/UsILB1qsku6HO+l0axYr36SgFPTLmrRBN8alMCOMZTIvhmYz27K+gKTkvxrWtco3sPfjNhrLBbEZOw3Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=BqiS3QFj; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="BqiS3QFj" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9846AC19423; Tue, 31 Mar 2026 16:49:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1774975753; bh=bQYArPzY/siTpP7U3fgPGvC1BttN5s1ntOkESjt0SEk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=BqiS3QFjKkBeNOs5rnNbDfK/Jj/qXRsY+OuBbeOi0IeoO+m7kqfshHaL/4BV6fAz4 DpgqVCA56pgbdXMFgs924ZvPf65m3tloTsMIK2pUYmX9NskoQqJ4OiiQOvk/ZQfTZw O1ClKpA6DWWvLT9jwjXyGToxwVrlVUbmSjINNfuA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Arnd Bergmann , Josh Poimboeuf , Sasha Levin Subject: [PATCH 6.12 040/244] objtool: Handle Clang RSP musical chairs Date: Tue, 31 Mar 2026 18:19:50 +0200 Message-ID: <20260331161743.179407713@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260331161741.651718120@linuxfoundation.org> References: <20260331161741.651718120@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Josh Poimboeuf [ Upstream commit 7fdaa640c810cb42090a182c33f905bcc47a616a ] For no apparent reason (possibly related to CONFIG_KMSAN), Clang can randomly pass the value of RSP to other registers and then back again to RSP. Handle that accordingly. Fixes the following warnings: drivers/input/misc/uinput.o: warning: objtool: uinput_str_to_user+0x165: undefined stack state drivers/input/misc/uinput.o: warning: objtool: uinput_str_to_user+0x165: unknown CFA base reg -1 Reported-by: Arnd Bergmann Closes: https://lore.kernel.org/90956545-2066-46e3-b547-10c884582eb0@app.fastmail.com Link: https://patch.msgid.link/240e6a172cc73292499334a3724d02ccb3247fc7.1772818491.git.jpoimboe@kernel.org Signed-off-by: Josh Poimboeuf Signed-off-by: Sasha Levin --- tools/objtool/arch/x86/decode.c | 62 ++++++++++++--------------------- tools/objtool/check.c | 14 ++++++++ 2 files changed, 37 insertions(+), 39 deletions(-) diff --git a/tools/objtool/arch/x86/decode.c b/tools/objtool/arch/x86/decode.c index ed6bff0e01dcd..f96b7b47babd5 100644 --- a/tools/objtool/arch/x86/decode.c +++ b/tools/objtool/arch/x86/decode.c @@ -331,52 +331,36 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec if (!rex_w) break; - if (modrm_reg == CFI_SP) { - - if (mod_is_reg()) { - /* mov %rsp, reg */ - ADD_OP(op) { - op->src.type = OP_SRC_REG; - op->src.reg = CFI_SP; - op->dest.type = OP_DEST_REG; - op->dest.reg = modrm_rm; - } - break; - - } else { - /* skip RIP relative displacement */ - if (is_RIP()) - break; - - /* skip nontrivial SIB */ - if (have_SIB()) { - modrm_rm = sib_base; - if (sib_index != CFI_SP) - break; - } - - /* mov %rsp, disp(%reg) */ - ADD_OP(op) { - op->src.type = OP_SRC_REG; - op->src.reg = CFI_SP; - op->dest.type = OP_DEST_REG_INDIRECT; - op->dest.reg = modrm_rm; - op->dest.offset = ins.displacement.value; - } - break; + if (mod_is_reg()) { + /* mov reg, reg */ + ADD_OP(op) { + op->src.type = OP_SRC_REG; + op->src.reg = modrm_reg; + op->dest.type = OP_DEST_REG; + op->dest.reg = modrm_rm; } - break; } - if (rm_is_reg(CFI_SP)) { + /* skip RIP relative displacement */ + if (is_RIP()) + break; - /* mov reg, %rsp */ + /* skip nontrivial SIB */ + if (have_SIB()) { + modrm_rm = sib_base; + if (sib_index != CFI_SP) + break; + } + + /* mov %rsp, disp(%reg) */ + if (modrm_reg == CFI_SP) { ADD_OP(op) { op->src.type = OP_SRC_REG; - op->src.reg = modrm_reg; - op->dest.type = OP_DEST_REG; - op->dest.reg = CFI_SP; + op->src.reg = CFI_SP; + op->dest.type = OP_DEST_REG_INDIRECT; + op->dest.reg = modrm_rm; + op->dest.offset = ins.displacement.value; } break; } diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 4adb3f3d9aed8..ad83bb3197225 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -3021,6 +3021,20 @@ static int update_cfi_state(struct instruction *insn, cfi->stack_size += 8; } + else if (cfi->vals[op->src.reg].base == CFI_CFA) { + /* + * Clang RSP musical chairs: + * + * mov %rsp, %rdx [handled above] + * ... + * mov %rdx, %rbx [handled here] + * ... + * mov %rbx, %rsp [handled above] + */ + cfi->vals[op->dest.reg].base = CFI_CFA; + cfi->vals[op->dest.reg].offset = cfi->vals[op->src.reg].offset; + } + break; -- 2.51.0