From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.zytor.com (terminus.zytor.com [198.137.202.136]) (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 79BC32765C4; Tue, 10 Feb 2026 04:16:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.136 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770697010; cv=none; b=Bzl+nfsfhn9ynKfBg9pmpa6gOE4BQct5aROPioHiEmvCiRmY9+ckvLLAdfXqiFP2DGCEbdBFIQBDKahJgvVthzuy57lDF+u9K4tAmVxxMury2kS3+lc+XUWdsGQ/+CldGVgSAvEsQ6DPXXllSG5XS42tKxLgul5J5L44TvhrS40= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770697010; c=relaxed/simple; bh=dShp/s0xOahHfZuk2rk8o5k/pdR7As113m62F4PaSDw=; h=Date:From:To:CC:Subject:In-Reply-To:References:Message-ID: MIME-Version:Content-Type; b=H7lxd4QndoxvLz/uXOiQ9wNL6lFz5EXTt3knokyOzKrTpZFQRKWu4Yolg3ODLuqOARNrSrL+3CyuDHkrMSLTmUahCsKAZk6iBUzz7BGHEQM9ZD/bTukYFUtSsuTPKe+DYf//BYraK6dpyo2MMVqGPMzZCDs70v0+kQSIpNIGcNk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zytor.com; spf=pass smtp.mailfrom=zytor.com; dkim=fail (2048-bit key) header.d=zytor.com header.i=@zytor.com header.b=bPjZ9Y2g reason="signature verification failed"; arc=none smtp.client-ip=198.137.202.136 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zytor.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=zytor.com Authentication-Results: smtp.subspace.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=zytor.com header.i=@zytor.com header.b="bPjZ9Y2g" Received: from ehlo.thunderbird.net (c-76-133-66-138.hsd1.ca.comcast.net [76.133.66.138]) (authenticated bits=0) by mail.zytor.com (8.18.1/8.17.1) with ESMTPSA id 61A4Fqvg3149966 (version=TLSv1.3 cipher=TLS_AES_128_GCM_SHA256 bits=128 verify=NO); Mon, 9 Feb 2026 20:15:53 -0800 DKIM-Filter: OpenDKIM Filter v2.11.0 mail.zytor.com 61A4Fqvg3149966 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zytor.com; s=2026012301; t=1770696956; bh=lMA+e7t1AQwEppF56ecV3ZH9XLnQSHpFgr1CYZ9e58g=; h=Date:From:To:CC:Subject:In-Reply-To:References:From; b=bPjZ9Y2gc8XthT6zR8auXTW7LY0+PoYLaGLDTGvP5fag/zuiuP5tQ6Cv1wveyTm57 ErTx2dN99MNaspd+H16qZxFGNWq4gETPUsrJoDgKj1PTeMhC7npPFbbF4bIVa8hIoO NukcLD2uJLbiJ77RYGLeLH/E/TPTD31/BxU422+TVn8WU5ZP6uSWIObtIO9TNOQPtb WrO0aiPQ/p3gP3xcrmc3gdEICDoxjGG11jNeQb1yAwO2td78+CCqjwFIVAJD9j7qFu w8xSdWmfKueV84Yjuxx6TQ07qAZiYO5eLrXtTlCq8NvgnA8cMYxrSIKl+Ol4AJQrzF 13NMFFJ2qFaNg== Date: Mon, 09 Feb 2026 20:15:46 -0800 From: "H. Peter Anvin" To: Xi Ruoyao , Jens Remus CC: "Jason A. Donenfeld" , "Peter Zijlstra (Intel)" , "Theodore Ts'o" , =?ISO-8859-1?Q?Thomas_Wei=DFschuh?= , Xin Li , Andrew Cooper , Andy Lutomirski , Ard Biesheuvel , Borislav Petkov , Brian Gerst , Dave Hansen , Ingo Molnar , James Morse , Jarkko Sakkinen , Josh Poimboeuf , Kees Cook , Nam Cao , Oleg Nesterov , Perry Yuan , Thomas Gleixner , Thomas Huth , Uros Bizjak , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-sgx@vger.kernel.org, x86@kernel.org, Indu Bhagat , Claudiu Zissulescu-Ianculescu , Heiko Carstens , Vasily Gorbik Subject: =?US-ASCII?Q?Re=3A_=5BPATCH_v4=2E1_06/10=5D_x86/entry/vdso32?= =?US-ASCII?Q?=3A_remove_open-coded_DWARF_in_sigreturn=2ES?= User-Agent: K-9 Mail for Android In-Reply-To: References: <20260106211856.560186-6-hpa@zytor.com> <223707e2-3231-4037-bd1f-490ddf6aeeb6@linux.ibm.com> Message-ID: <29D95765-BD93-451D-8FD8-54250ADE1DEB@zytor.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On February 9, 2026 7:11:25 PM PST, Xi Ruoyao wrote: >On Mon, 2026-02-02 at 19:57 -0800, H=2E Peter Anvin wrote: >> That hack dates back from before the signal frame extension=2E It is no >> longer necessary=2E > >Unfortunately at least it seems libgcc unwinder does not handle the >signal frame extension properly=2E The code reads: > > fde =3D _Unwind_Find_FDE (context->ra + _Unwind_IsSignalFrame (context)= - 1,=20 > &context->bases); > if (fde =3D=3D NULL) > { =20 >#ifdef MD_FALLBACK_FRAME_STATE_FOR > /* Couldn't find frame unwind info for this function=2E Try a > target-specific fallback mechanism=2E This will necessarily > not provide a personality routine or LSDA=2E */ > return MD_FALLBACK_FRAME_STATE_FOR (context, fs);=20 >#else > return _URC_END_OF_STACK; >#endif > } =20 > > fs->pc =3D context->bases=2Efunc; > > cie =3D get_cie (fde); > insn =3D extract_cie_info (cie, context, fs);=20 > >Thus, it indeed attempts to avoid subtracting 1 for a signal frame, but >=2E=2E=2E _Unwind_IsSignalFrame (context) actually extracts a flag in con= text >which will only be raised up by extract_cie_info=2E > >Or am I missing something here? > Oh, good grief=2E=2E=2E How does this possibly work on non-x86 platforms?