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[3.8.y.z,extended,stable] Patch "ACPI / PM: Walk physical_node_list under physical_node_lock" has been added to staging queue

Message ID 1376606877-22521-1-git-send-email-kamal@canonical.com
State New
Headers show

Commit Message

Kamal Mostafa Aug. 15, 2013, 10:47 p.m. UTC
This is a note to let you know that I have just added a patch titled

    ACPI / PM: Walk physical_node_list under physical_node_lock

to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.7.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

From a3cd9f82f1029aeb4c1a5af856d87d948c629ffb Mon Sep 17 00:00:00 2001
From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Date: Tue, 6 Aug 2013 02:26:22 +0200
Subject: ACPI / PM: Walk physical_node_list under physical_node_lock

commit 623cf33cb055b1e81fa47e4fc16789b2c129e31e upstream.

The list of physical devices corresponding to an ACPI device
object is walked by acpi_system_wakeup_device_seq_show() and
physical_device_enable_wakeup() without taking that object's
physical_node_lock mutex.  Since each of those functions may be
run at any time as a result of a user space action, the lack of
appropriate locking in them may lead to a kernel crash if that
happens during device hot-add or hot-remove involving the device
object in question.

Fix the issue by modifying acpi_system_wakeup_device_seq_show() and
physical_device_enable_wakeup() to use physical_node_lock as
appropriate.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
 drivers/acpi/proc.c | 8 ++++++++
 1 file changed, 8 insertions(+)

--
1.8.1.2
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Patch

diff --git a/drivers/acpi/proc.c b/drivers/acpi/proc.c
index 52ce767..8fa2d08 100644
--- a/drivers/acpi/proc.c
+++ b/drivers/acpi/proc.c
@@ -311,6 +311,8 @@  acpi_system_wakeup_device_seq_show(struct seq_file *seq, void *offset)
 			   dev->pnp.bus_id,
 			   (u32) dev->wakeup.sleep_state);

+		mutex_lock(&dev->physical_node_lock);
+
 		if (!dev->physical_node_count) {
 			seq_printf(seq, "%c%-8s\n",
 				dev->wakeup.flags.run_wake ? '*' : ' ',
@@ -338,6 +340,8 @@  acpi_system_wakeup_device_seq_show(struct seq_file *seq, void *offset)
 				put_device(ldev);
 			}
 		}
+
+		mutex_unlock(&dev->physical_node_lock);
 	}
 	mutex_unlock(&acpi_device_lock);
 	return 0;
@@ -347,12 +351,16 @@  static void physical_device_enable_wakeup(struct acpi_device *adev)
 {
 	struct acpi_device_physical_node *entry;

+	mutex_lock(&adev->physical_node_lock);
+
 	list_for_each_entry(entry,
 		&adev->physical_node_list, node)
 		if (entry->dev && device_can_wakeup(entry->dev)) {
 			bool enable = !device_may_wakeup(entry->dev);
 			device_set_wakeup_enable(entry->dev, enable);
 		}
+
+	mutex_unlock(&adev->physical_node_lock);
 }

 static ssize_t