linux-kernel - [PATCH 2/2] pci, acpi: free IO resource during shutdown

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Message-Id: <1457389310-3538-2-git-send-email-okaya@codeaurora.org>
Date:	Mon,  7 Mar 2016 17:21:50 -0500
From:	Sinan Kaya <okaya@...eaurora.org>
To:	linux-pci@...r.kernel.org, linux-acpi@...r.kernel.org,
	timur@...eaurora.org, cov@...eaurora.org, jcm@...hat.com
Cc:	agross@...eaurora.org, linux-arm-msm@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	Sinan Kaya <okaya@...eaurora.org>, linux-kernel@...r.kernel.org
Subject: [PATCH 2/2] pci, acpi: free IO resource during shutdown

The ACPI PCI driver is leaking out memory mappings
when a slot is removed. Upon insertion following a
removal, we are hitting a BUG statement. Second call
to the remap API hits a bug statement because the area is
already mapped. This patch releases additional virtual
memory mapped by pci_remap_iospace function as part of
__release_pci_root_info function if the region type is IO.

 BUG: failure at kernel/lib/ioremap.c:31/ioremap_pte_range()!
 Kernel panic - not syncing: BUG!
 CPU: 1 PID: 630 Comm: kworker/u48:3 Not tainted
 Workqueue: kacpi_hotplug acpi_hotplug_work_fn Call trace:
 dump_backtrace+0x0/0x10c [<ffff800000086e58>]
 show_stack+0x10/0x1c [<ffff8000004d1f50>]
 dump_stack+0x74/0xc4
 panic+0xe4/0x21c [<ffff8000002577cc>]
 ioremap_page_range+0x290/0x30c [<ffff8000002861dc>]
 pci_remap_iospace+0x88/0xa0 [<ffff8000000908f8>]
 setup_resource+0x114/0x16c [<ffff8000002c0fc0>]
 acpi_walk_resource_buffer+0x54/0xb0
 acpi_walk_resources+0x90/0xbc
 pci_acpi_scan_root+0x184/0x2d0
 acpi_pci_root_add+0x368/0x434
 acpi_bus_attach+0x124/0x22c [<ffff8000002a5628>]
 acpi_bus_scan+0x58/0x74 [<ffff8000002a57c0>]
 acpi_device_hotplug+0xc4/0x3f0 [<ffff8000002a0468>]
 acpi_hotplug_work_fn+0x1c/0x34 [<ffff8000000b9310>]
 process_one_work+0x1e8/0x308 [<ffff8000000b9b04>]
 worker_thread+0x294/0x3cc  [<ffff8000000bd9

Signed-off-by: Sinan Kaya <okaya@...eaurora.org>
---
 drivers/acpi/pci_root.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index 71bbfae..6d4bc2d 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -946,6 +946,8 @@ static void acpi_pci_root_release_info(struct pci_host_bridge *bridge)

 	resource_list_for_each_entry(entry, &bridge->windows) {
 		res = entry->res;
+		if (res->flags & IORESOURCE_IO)
+			pci_unmap_iospace(res);
 		if (res->parent &&
 		    (res->flags & (IORESOURCE_MEM | IORESOURCE_IO)))
 			release_resource(res);
-- 
1.8.2.1