From nobody Thu Apr 9 09:04:45 2026 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (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 ED3C536AB7C; Mon, 9 Mar 2026 19:54:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773086056; cv=none; b=PDNKCqhyGskYKqhGyxm+Q/xCLuNBQiTi4JOckdAMEA2hdxoEOQVGbInvxb8RrDW5InXzKwYoQHbKBz5uhIz0Zu/xjYc7h6J7mpVPTRmbYELU4z0Vy9DVpY/oIsJUvHh1ZOs93yQBQErOz5CFkuZIlouOjutrqMgGiXe9ofmWA8g= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773086056; c=relaxed/simple; bh=Igv/CiVzdEQXYqqNBd9xbHmvBrqGCcTRG3YIAFFQcW0=; h=Date:From:To:Subject:Cc:In-Reply-To:References:MIME-Version: Message-ID:Content-Type; b=haWgi+61stLdeWM6CvXqsL7dcqQ/GK2Wgx3PLr1wXUpXcAy7T0SAMpHRTfhyjGOglvMppyMxuOp3TsPEF4ACgjmsgVFsPUsI4H/Vjh1xAL28hh01odub2ZW+yd75jrlpZ8Ew/FqFGC8J3llOFJ48G8vB219BLpeQ9GcEiPuizcg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=lCg3B8jp; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=MI52TF/r; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="lCg3B8jp"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="MI52TF/r" Date: Mon, 09 Mar 2026 19:54:12 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1773086053; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=aObbEGszkdBxXRkt2JBb1Rn0rtGJgiewhzsar9e2LtM=; b=lCg3B8jp2EFw78htAcWWMBr6Y0xYgkkBZzOhlVfSggx8ljLUrzQmMluA3I/vsWuKA6Ukbh ee1gJ2vuJloLmr0BeNY7A2QsrBsmoojdZVCOFTqiXVol6Y7gCMa6caFR9+X7kWUCY2aZJW 22UKlRgR5sqqKGJAou5Y3uP/6Qh2RmtSf/Mzr8zys9sTnV7Td+Umjk/Xy/8SbRFpKCuB6F cNe2COFlMUL7R1tgUNK2K6WwQnoIomLXPixcZFYZ29bKuSZW9z1HheKDn2lD7cLYS40toD fCoBNoT1d26UOP/jh+daRSYK2CqK55hjtouzAl0PCg+hX57m2Y9T4UpXS4vBsA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1773086053; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=aObbEGszkdBxXRkt2JBb1Rn0rtGJgiewhzsar9e2LtM=; b=MI52TF/rTmDr3w2P9wY3cFE6L5BJi4jfhgiFubzoGM3lCk3YJyv2c66xEWp2548bP4oV3p Ae1wn7CgZSGSHxAw== From: "tip-bot2 for Josh Poimboeuf" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: objtool/urgent] objtool: Handle Clang RSP musical chairs Cc: Arnd Bergmann , Josh Poimboeuf , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <240e6a172cc73292499334a3724d02ccb3247fc7.1772818491.git.jpoimboe@kernel.org> References: <240e6a172cc73292499334a3724d02ccb3247fc7.1772818491.git.jpoimboe@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-ID: <177308605242.1647592.16704999572041610391.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Precedence: bulk Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable The following commit has been merged into the objtool/urgent branch of tip: Commit-ID: 7fdaa640c810cb42090a182c33f905bcc47a616a Gitweb: https://git.kernel.org/tip/7fdaa640c810cb42090a182c33f905bcc= 47a616a Author: Josh Poimboeuf AuthorDate: Fri, 06 Mar 2026 09:35:06 -08:00 Committer: Josh Poimboeuf CommitterDate: Mon, 09 Mar 2026 08:45:10 -07:00 objtool: Handle Clang RSP musical chairs 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.fa= stmail.com Link: https://patch.msgid.link/240e6a172cc73292499334a3724d02ccb3247fc7.177= 2818491.git.jpoimboe@kernel.org Signed-off-by: Josh Poimboeuf --- 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/decod= e.c index 73bfea2..c581782 100644 --- a/tools/objtool/arch/x86/decode.c +++ b/tools/objtool/arch/x86/decode.c @@ -395,52 +395,36 @@ int arch_decode_instruction(struct objtool_file *file= , const struct section *sec if (!rex_w) break; =20 - if (modrm_reg =3D=3D CFI_SP) { - - if (mod_is_reg()) { - /* mov %rsp, reg */ - ADD_OP(op) { - op->src.type =3D OP_SRC_REG; - op->src.reg =3D CFI_SP; - op->dest.type =3D OP_DEST_REG; - op->dest.reg =3D modrm_rm; - } - break; - - } else { - /* skip RIP relative displacement */ - if (is_RIP()) - break; - - /* skip nontrivial SIB */ - if (have_SIB()) { - modrm_rm =3D sib_base; - if (sib_index !=3D CFI_SP) - break; - } - - /* mov %rsp, disp(%reg) */ - ADD_OP(op) { - op->src.type =3D OP_SRC_REG; - op->src.reg =3D CFI_SP; - op->dest.type =3D OP_DEST_REG_INDIRECT; - op->dest.reg =3D modrm_rm; - op->dest.offset =3D ins.displacement.value; - } - break; + if (mod_is_reg()) { + /* mov reg, reg */ + ADD_OP(op) { + op->src.type =3D OP_SRC_REG; + op->src.reg =3D modrm_reg; + op->dest.type =3D OP_DEST_REG; + op->dest.reg =3D modrm_rm; } - break; } =20 - if (rm_is_reg(CFI_SP)) { + /* skip RIP relative displacement */ + if (is_RIP()) + break; =20 - /* mov reg, %rsp */ + /* skip nontrivial SIB */ + if (have_SIB()) { + modrm_rm =3D sib_base; + if (sib_index !=3D CFI_SP) + break; + } + + /* mov %rsp, disp(%reg) */ + if (modrm_reg =3D=3D CFI_SP) { ADD_OP(op) { op->src.type =3D OP_SRC_REG; - op->src.reg =3D modrm_reg; - op->dest.type =3D OP_DEST_REG; - op->dest.reg =3D CFI_SP; + op->src.reg =3D CFI_SP; + op->dest.type =3D OP_DEST_REG_INDIRECT; + op->dest.reg =3D modrm_rm; + op->dest.offset =3D ins.displacement.value; } break; } diff --git a/tools/objtool/check.c b/tools/objtool/check.c index a30379e..786b2f2 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -3000,6 +3000,20 @@ static int update_cfi_state(struct instruction *insn, cfi->stack_size +=3D 8; } =20 + else if (cfi->vals[op->src.reg].base =3D=3D 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 =3D CFI_CFA; + cfi->vals[op->dest.reg].offset =3D cfi->vals[op->src.reg].offset; + } + =20 break; =20