From nobody Sat Dec 27 22:50:43 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7DF71C4332F for ; Thu, 14 Dec 2023 16:52:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1443694AbjLNQwA (ORCPT ); Thu, 14 Dec 2023 11:52:00 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52962 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230314AbjLNQvm (ORCPT ); Thu, 14 Dec 2023 11:51:42 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F3924D66 for ; Thu, 14 Dec 2023 08:51:11 -0800 (PST) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0D7C4C433C8; Thu, 14 Dec 2023 16:51:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1702572671; bh=/Qylc2+JKzSkPgqtG0O15AfjjZ9hpoVXvrfTV9+uIPA=; h=From:To:Cc:Subject:Date:From; b=Rw4g39EK4Oz975BOvXZXh6h9gnLJDQFsGE9qj6QwJbbXn59dZWCY2oC+Jm3rfAJry poOCUcsm5X+40s3GlTO52kgrnj8YITcOc8xNYA9lzI3rzVZ48/So37jLNPuXi5sbOq C9jCLamZVMBCmLWwVCTl68hCpTqTisLsU5MO2FEQKSAeRPPYCq2oxJopZKk4ICoOn3 dxaryI8HdITj+XGWhhuItNYvo/lJfoUbElVMMu5siFy2DptQgaaeVuPYyUIn8rvo4g Buom6W9VT0cFvLFIF6fUTqIM4NPW1TL3yfM7JrlklrOCfbQzj3yVFllQeMbtzQxG/l AxXqeB39K3a6A== From: Bjorn Helgaas To: linux-pci@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Igor Mammedov , Fiona Ebner , Dongli Zhang , Jonathan Woithe , "Rafael J . Wysocki" , "Michael S . Tsirkin" , Bjorn Helgaas , stable@vger.kernel.org Subject: [PATCH] Revert "PCI: acpiphp: Reassign resources on bridge if necessary" Date: Thu, 14 Dec 2023 10:51:02 -0600 Message-Id: <20231214165102.1093961-1-helgaas@kernel.org> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Bjorn Helgaas This reverts commit 40613da52b13fb21c5566f10b287e0ca8c12c4e9 and the subsequent fix to it: cc22522fd55e ("PCI: acpiphp: Use pci_assign_unassigned_bridge_resources()= only for non-root bus") 40613da52b13 fixed a problem where hot-adding a device with large BARs failed if the bridge windows programmed by firmware were not large enough. cc22522fd55e ("PCI: acpiphp: Use pci_assign_unassigned_bridge_resources() only for non-root bus") fixed a problem with 40613da52b13: an ACPI hot-add of a device on a PCI root bus (common in the virt world) or firmware sending ACPI Bus Check to non-existent Root Ports (e.g., on Dell Inspiron 7352/0W6WV0) caused a NULL pointer dereference and suspend/resume hangs. Unfortunately the combination of 40613da52b13 and cc22522fd55e caused other problems: - Fiona reported that hot-add of SCSI disks in QEMU virtual machine fails sometimes. - Dongli reported a similar problem with hot-add of SCSI disks. - Jonathan reported a console freeze during boot on bare metal due to an error in radeon GPU initialization. Revert both patches to avoid adding these problems. This means we will again see the problems with hot-adding devices with large BARs and the NULL pointer dereferences and suspend/resume issues that 40613da52b13 and cc22522fd55e were intended to fix. Fixes: 40613da52b13 ("PCI: acpiphp: Reassign resources on bridge if necessa= ry") Fixes: cc22522fd55e ("PCI: acpiphp: Use pci_assign_unassigned_bridge_resour= ces() only for non-root bus") Reported-by: Fiona Ebner Closes: https://lore.kernel.org/r/9eb669c0-d8f2-431d-a700-6da13053ae54@prox= mox.com Reported-by: Dongli Zhang Closes: https://lore.kernel.org/r/3c4a446a-b167-11b8-f36f-d3c1b49b42e9@orac= le.com Reported-by: Jonathan Woithe Closes: https://lore.kernel.org/r/ZXpaNCLiDM+Kv38H@marvin.atrad.com.au Signed-off-by: Bjorn Helgaas Cc: Cc: Igor Mammedov Acked-by: Igor Mammedov Acked-by: Michael S. Tsirkin --- drivers/pci/hotplug/acpiphp_glue.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpip= hp_glue.c index 601129772b2d..5b1f271c6034 100644 --- a/drivers/pci/hotplug/acpiphp_glue.c +++ b/drivers/pci/hotplug/acpiphp_glue.c @@ -512,15 +512,12 @@ static void enable_slot(struct acpiphp_slot *slot, bo= ol bridge) if (pass && dev->subordinate) { check_hotplug_bridge(slot, dev); pcibios_resource_survey_bus(dev->subordinate); - if (pci_is_root_bus(bus)) - __pci_bus_size_bridges(dev->subordinate, &add_list); + __pci_bus_size_bridges(dev->subordinate, + &add_list); } } } - if (pci_is_root_bus(bus)) - __pci_bus_assign_resources(bus, &add_list, NULL); - else - pci_assign_unassigned_bridge_resources(bus->self); + __pci_bus_assign_resources(bus, &add_list, NULL); } =20 acpiphp_sanitize_bus(bus); --=20 2.34.1