From patchwork Wed Jul 26 12:35:18 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Igor Mammedov X-Patchwork-Id: 706676 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 F1E73C41513 for ; Wed, 26 Jul 2023 12:36:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233424AbjGZMgP (ORCPT ); Wed, 26 Jul 2023 08:36:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43550 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233346AbjGZMgN (ORCPT ); Wed, 26 Jul 2023 08:36:13 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 82E871FEF for ; Wed, 26 Jul 2023 05:35:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1690374926; h=from:from: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=XrRclP6rIDLOdKio+U8eIclA36kjoF7aS12oWTBS7Y8=; b=SH5qGEYvSB4HjIar2LqyR/gNL1mViwTG4Nibve5TzFmidKHbz0nCK9qLYTO7nXnm1zTiE6 zPYRCB4dm+FX4VPq/U+oGp4FK5T93ukdDIIkUDV8A9foQw2zonAxPl1h8OKAAdyCN7jeCy 01gqoONTi3ddP3mcZ00mw3UcEGiszyc= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-266-wce5mkF9M-aFlY9zMsp0fg-1; Wed, 26 Jul 2023 08:35:23 -0400 X-MC-Unique: wce5mkF9M-aFlY9zMsp0fg-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 0550F805951; Wed, 26 Jul 2023 12:35:23 +0000 (UTC) Received: from dell-r430-03.lab.eng.brq2.redhat.com (dell-r430-03.lab.eng.brq2.redhat.com [10.37.153.18]) by smtp.corp.redhat.com (Postfix) with ESMTP id A4576492B01; Wed, 26 Jul 2023 12:35:21 +0000 (UTC) From: Igor Mammedov To: linux-kernel@vger.kernel.org Cc: terraluna977@gmail.com, bhelgaas@google.com, linux-pci@vger.kernel.org, imammedo@redhat.com, mst@redhat.com, rafael@kernel.org, linux-acpi@vger.kernel.org Subject: [PATCH 1/1] PCI: acpiphp:: use pci_assign_unassigned_bridge_resources() only if bus->self not NULL Date: Wed, 26 Jul 2023 14:35:18 +0200 Message-Id: <20230726123518.2361181-2-imammedo@redhat.com> In-Reply-To: <20230726123518.2361181-1-imammedo@redhat.com> References: <20230726123518.2361181-1-imammedo@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.9 Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org Commit [1] switched acpiphp hotplug to use pci_assign_unassigned_bridge_resources() which depends on bridge being available, however in some cases when acpiphp is in use, enable_slot() can get a slot without bridge associated. 1. legitimate case of hotplug on root bus (likely not exiting on real hw, but widely used in virt world) 2. broken firmware, that sends 'Bus check' events to non existing root ports (Dell Inspiron 7352/0W6WV0), which somehow endup at acpiphp:enable_slot(..., bridge = 0) and with bus without bridge assigned to it. Issue is easy to reproduce with QEMU's 'pc' machine provides PCI hotplug on hostbridge slots. to reproduce boot kernel at commit [1] in VM started with followin CLI and hotplug a device: once guest OS is fully booted at qemu prompt: (qemu) device_add e1000 it will cause NULL pointer dereference at void pci_assign_unassigned_bridge_resources(struct pci_dev *bridge) { struct pci_bus *parent = bridge->subordinate; [ 612.277651] BUG: kernel NULL pointer dereference, address: 0000000000000018 [...] [ 612.277798] ? pci_assign_unassigned_bridge_resources+0x1f/0x260 [ 612.277804] ? pcibios_allocate_dev_resources+0x3c/0x2a0 [ 612.277809] enable_slot+0x21f/0x3e0 [ 612.277816] acpiphp_hotplug_notify+0x13d/0x260 [ 612.277822] ? __pfx_acpiphp_hotplug_notify+0x10/0x10 [ 612.277827] acpi_device_hotplug+0xbc/0x540 [ 612.277834] acpi_hotplug_work_fn+0x15/0x20 [ 612.277839] process_one_work+0x1f7/0x370 [ 612.277845] worker_thread+0x45/0x3b0 [ 612.277850] ? __pfx_worker_thread+0x10/0x10 [ 612.277854] kthread+0xdc/0x110 [ 612.277860] ? __pfx_kthread+0x10/0x10 [ 612.277866] ret_from_fork+0x28/0x40 [ 612.277871] ? __pfx_kthread+0x10/0x10 [ 612.277876] ret_from_fork_asm+0x1b/0x30 The issue was discovered on Dell Inspiron 7352/0W6WV0 laptop with following sequence: 1. suspend to RAM 2. wake up with the same backtrace being observed: 3. 2nd suspend to RAM attempt makes laptop freeze Fix it by using __pci_bus_assign_resources() instead of pci_assign_unassigned_bridge_resources()as we used to do but only in case when bus doesn't have a bridge associated with it. That let us keep hotplug on root bus working like it used to be but at the same time keeps resource reassignment usable on root ports (and other 1st level bridges) that was fixed by [1]. 1) Fixes: 40613da52b13 ("PCI: acpiphp: Reassign resources on bridge if necessary") Link: https://lore.kernel.org/r/11fc981c-af49-ce64-6b43-3e282728bd1a@gmail.com Reported-by: Woody Suwalski Signed-off-by: Igor Mammedov Acked-by: Rafael J. Wysocki Acked-by: Michael S. Tsirkin --- drivers/pci/hotplug/acpiphp_glue.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c index 328d1e416014..3bc4e1f3efee 100644 --- a/drivers/pci/hotplug/acpiphp_glue.c +++ b/drivers/pci/hotplug/acpiphp_glue.c @@ -498,6 +498,7 @@ static void enable_slot(struct acpiphp_slot *slot, bool bridge) acpiphp_native_scan_bridge(dev); } } else { + LIST_HEAD(add_list); int max, pass; acpiphp_rescan_slot(slot); @@ -511,10 +512,15 @@ static void enable_slot(struct acpiphp_slot *slot, bool bridge) if (pass && dev->subordinate) { check_hotplug_bridge(slot, dev); pcibios_resource_survey_bus(dev->subordinate); + if (!bus->self) + __pci_bus_size_bridges(dev->subordinate, &add_list); } } } - pci_assign_unassigned_bridge_resources(bus->self); + if (bus->self) + pci_assign_unassigned_bridge_resources(bus->self); + else + __pci_bus_assign_resources(bus, &add_list, NULL); } acpiphp_sanitize_bus(bus);