From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 EA45B36B935; Sat, 22 Aug 2026 08:40:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787388034; cv=none; b=qQGNR+jIAm8NJZOELpjtIcUT50uvCVTx5iHcECo4OxURhzQJFvqdOhzJ9hIPtflNhXbZICRLTtay+H5F6tWwZxbGj5NhXpCSEWGJ+nvGZjqmQdMeogKvq8YRJSD8ULXxt5MsfC1W0B0np8V1xM1QNy49XWwL7M/AtTOSfATUqK8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787388034; c=relaxed/simple; bh=RIGayfiO2+lLMSnzf+4DCjdX0jqyzt4cOKs+zg5dHYs=; h=Date:Message-ID:From:To:Cc:Subject:In-Reply-To:References: MIME-Version:Content-Type; b=JbbJJ3mi9JRNUMNokvYKqVFi+Jk9u60V0U2zOldAyWhPOACcnCd0KTihz7Kzr5vdJkALMzjrnF5PQeSrLAZ0FKFEpzXxhOg2igvYuFnok3iVeQAypoFUTeIeb5SucWCTsKQAIFyrq8h7SousnrEefVLLFKknqxlEqvtz7AJO2rU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=RCdeEWOl; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="RCdeEWOl" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7D00A1F000E9; Sat, 22 Aug 2026 08:40:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1787388030; bh=goS0hO9F9PB7GW9OY4RoUpd4niO++BgWcgqth7XojbQ=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=RCdeEWOl7vwP1easXifPNcEyw4TI9oZUWFv5A1RU6B3fxLxq9AvRr28vJjMKPpvO6 OubQ97d9U7wPbWvXMmFxbcsaxDsoxlRleDvSeqq/70aPfuTgsgYa4aYB/GJ+Mk49Q+ FO4kXaByqE1uzQ9vufOYXrdw2H9oAlouqVPFbgM0aVe0JEGo9ceAmy4qbk1VHlqSUC bgHU1ukKRmct/nKHNaYA/+zKxP+xHhkkfD/tWqKNB2VufWYdxm1WPbL9dcwB23chYz I91SPZ+39OlX3L28S0gNLQLsOa5prphUE8zHyuZKXobdb475E20IU08wi8M7E7FFdg g3OgOKAN9To4g== Received: from sofa.misterjones.org ([185.219.108.64] helo=goblin-girl.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.98.2) (envelope-from ) id 1wxhHA-00000000EOp-2Ehu; Sat, 22 Aug 2026 08:40:28 +0000 Date: Sat, 22 Aug 2026 09:40:28 +0100 Message-ID: <86tsom4kg3.wl-maz@kernel.org> From: Marc Zyngier To: Karl Mehltretter Cc: Oliver Upton , kvmarm@lists.linux.dev, Fuad Tabba , Joey Gouly , Steffen Eiden , Suzuki K Poulose , Zenghui Yu , Catalin Marinas , Will Deacon , Paolo Bonzini , Shuah Khan , Eric Auger , Christoffer Dall , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: Re: [PATCH v2 3/5] KVM: arm64: vgic-v3: Unregister redistributors before freeing regions In-Reply-To: References: <20260819224229.82948-1-kmehltretter@gmail.com> <20260819224229.82948-4-kmehltretter@gmail.com> <874igpp3qm.wl-maz@kernel.org> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/30.1 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: kmehltretter@gmail.com, oupton@kernel.org, kvmarm@lists.linux.dev, tabba@google.com, joey.gouly@arm.com, seiden@linux.ibm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, catalin.marinas@arm.com, will@kernel.org, pbonzini@redhat.com, shuah@kernel.org, eric.auger@redhat.com, christoffer.dall@arm.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-kselftest@vger.kernel.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false On Fri, 21 Aug 2026 20:09:32 +0100, Karl Mehltretter wrote: >=20 > On Thu, Aug 20, 2026 at 09:58:57AM +0100, Marc Zyngier wrote: > > The other bit of interest is in __kvm_vgic_vcpu_destroy(), and its > > conditional removal of the RD iodevs. Can't we just get rid of this > > whole block altogether now that we have a saner failing path? >=20 > I tested removing that block. > It reintroduces the use-after-free fixed by ae8f8b376102 > (=E2=80=9CKVM: arm64: Unregister redistributor for failed vCPU creation= =E2=80=9D). At the very least: vgic_cpu->rd_iodev.base_addr =3D VGIC_ADDR_UNDEF; should be removed, as it serves no purpose anymore: all vcpus, valid or not, should now go through vgic_unregister_redist_iodev() which resets the value. It isn't massively useful on teardown anyway, so you might as well kill the extra one. M. --=20 Without deviation from the norm, progress is not possible.