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From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: ACPI Devel Maling List <linux-acpi@vger.kernel.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>,
	Aaron Lu <aaron.lu@intel.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Linux PCI <linux-pci@vger.kernel.org>,
	Mika Westerberg <mika.westerberg@linux.intel.com>,
	Robert Moore <robert.moore@intel.com>
Subject: [PATCH v3 2/7] ACPI / hotplug: Fix potential races in notify handlers
Date: Sun, 02 Feb 2014 18:15:02 +0100	[thread overview]
Message-ID: <1499994.Za93jVWRjt@vostro.rjw.lan> (raw)
In-Reply-To: <5157096.hCmU2aoKCT@vostro.rjw.lan>

From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

There is a slight possibility for the ACPI device object pointed to
by adev in acpi_hotplug_notify_cb() to become invalid between the
acpi_bus_get_device() that it comes from and the subsequent dereference
of that pointer under get_device().  Namely, if acpi_scan_drop_device()
runs in parallel with acpi_hotplug_notify_cb(), acpi_device_del_work_fn()
queued up by it may delete the device object in question right after
a successful execution of acpi_bus_get_device() in acpi_bus_notify().

An analogous problem is present in acpi_bus_notify() where the device
pointer coming from acpi_bus_get_device() may become invalid before
it subsequent dereference in the "if" block.

To prevent that from happening, introduce a new function,
acpi_bus_get_acpi_device(), working analogously to acpi_bus_get_device()
except that it will grab a reference to the ACPI device object returned
by it and it will do that under the ACPICA's namespace mutex.  Then,
make both acpi_hotplug_notify_cb() and acpi_bus_notify() use
acpi_bus_get_acpi_device() instead of acpi_bus_get_device() so as to
ensure that the pointers used by them will not become stale at one
point.

In addition to that, introduce acpi_bus_put_acpi_device() as a wrapper
around put_device() to be used along with acpi_bus_get_acpi_device()
and make the (new) users of the latter use acpi_bus_put_acpi_device()
too.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/acpi/bus.c      |    4 +++-
 drivers/acpi/internal.h |    2 ++
 drivers/acpi/scan.c     |   38 ++++++++++++++++++++++++++++++--------
 3 files changed, 35 insertions(+), 9 deletions(-)

Index: linux-pm/drivers/acpi/scan.c
===================================================================
--- linux-pm.orig/drivers/acpi/scan.c
+++ linux-pm/drivers/acpi/scan.c
@@ -476,7 +476,7 @@ static void acpi_device_hotplug(void *da
 
  out:
 	acpi_evaluate_hotplug_ost(adev->handle, src, ost_code, NULL);
-	put_device(&adev->dev);
+	acpi_bus_put_acpi_device(adev);
 	mutex_unlock(&acpi_scan_lock);
 	unlock_device_hotplug();
 }
@@ -488,9 +488,6 @@ static void acpi_hotplug_notify_cb(acpi_
 	struct acpi_device *adev;
 	acpi_status status;
 
-	if (acpi_bus_get_device(handle, &adev))
-		goto err_out;
-
 	switch (type) {
 	case ACPI_NOTIFY_BUS_CHECK:
 		acpi_handle_debug(handle, "ACPI_NOTIFY_BUS_CHECK event\n");
@@ -512,12 +509,14 @@ static void acpi_hotplug_notify_cb(acpi_
 		/* non-hotplug event; possibly handled by other handler */
 		return;
 	}
-	get_device(&adev->dev);
+	if (acpi_bus_get_acpi_device(handle, &adev))
+		goto err_out;
+
 	status = acpi_hotplug_execute(acpi_device_hotplug, adev, type);
 	if (ACPI_SUCCESS(status))
 		return;
 
-	put_device(&adev->dev);
+	acpi_bus_put_acpi_device(adev);
 
  err_out:
 	acpi_evaluate_hotplug_ost(handle, type, ost_code, NULL);
@@ -1112,14 +1111,16 @@ static void acpi_scan_drop_device(acpi_h
 	mutex_unlock(&acpi_device_del_lock);
 }
 
-int acpi_bus_get_device(acpi_handle handle, struct acpi_device **device)
+static int acpi_get_device_data(acpi_handle handle, struct acpi_device **device,
+				void (*callback)(void *))
 {
 	acpi_status status;
 
 	if (!device)
 		return -EINVAL;
 
-	status = acpi_get_data(handle, acpi_scan_drop_device, (void **)device);
+	status = acpi_get_data_full(handle, acpi_scan_drop_device,
+				    (void **)device, callback);
 	if (ACPI_FAILURE(status) || !*device) {
 		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No context for object [%p]\n",
 				  handle));
@@ -1127,8 +1128,29 @@ int acpi_bus_get_device(acpi_handle hand
 	}
 	return 0;
 }
+
+int acpi_bus_get_device(acpi_handle handle, struct acpi_device **device)
+{
+	return acpi_get_device_data(handle, device, NULL);
+}
 EXPORT_SYMBOL(acpi_bus_get_device);
 
+static void get_acpi_device(void *dev)
+{
+	if (dev)
+		get_device(&((struct acpi_device *)dev)->dev);
+}
+
+int acpi_bus_get_acpi_device(acpi_handle handle, struct acpi_device **adev_p)
+{
+	return acpi_get_device_data(handle, adev_p, get_acpi_device);
+}
+
+void acpi_bus_put_acpi_device(struct acpi_device *adev)
+{
+	put_device(&adev->dev);
+}
+
 int acpi_device_add(struct acpi_device *device,
 		    void (*release)(struct device *))
 {
Index: linux-pm/drivers/acpi/internal.h
===================================================================
--- linux-pm.orig/drivers/acpi/internal.h
+++ linux-pm/drivers/acpi/internal.h
@@ -81,6 +81,8 @@ bool acpi_scan_is_offline(struct acpi_de
 #define ACPI_STA_DEFAULT (ACPI_STA_DEVICE_PRESENT | ACPI_STA_DEVICE_ENABLED | \
 			  ACPI_STA_DEVICE_UI | ACPI_STA_DEVICE_FUNCTIONING)
 
+int acpi_bus_get_acpi_device(acpi_handle handle, struct acpi_device **adev_p);
+void acpi_bus_put_acpi_device(struct acpi_device *adev);
 int acpi_device_add(struct acpi_device *device,
 		    void (*release)(struct device *));
 void acpi_init_device_object(struct acpi_device *device, acpi_handle handle,
Index: linux-pm/drivers/acpi/bus.c
===================================================================
--- linux-pm.orig/drivers/acpi/bus.c
+++ linux-pm/drivers/acpi/bus.c
@@ -387,12 +387,14 @@ static void acpi_bus_notify(acpi_handle
 		break;
 	}
 
-	acpi_bus_get_device(handle, &device);
+	acpi_bus_get_acpi_device(handle, &device);
 	if (device) {
 		driver = device->driver;
 		if (driver && driver->ops.notify &&
 		    (driver->flags & ACPI_DRIVER_ALL_NOTIFY_EVENTS))
 			driver->ops.notify(device, type);
+
+		acpi_bus_put_acpi_device(device);
 	}
 }
 


  parent reply	other threads:[~2014-02-02 17:07 UTC|newest]

Thread overview: 100+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-01-27  0:37 [PATCH 0/11] ACPI / hotplug / PCI: Updates on top of changes merged recently Rafael J. Wysocki
2014-01-27  0:38 ` [PATCH 1/11] ACPI / hotplug / PCI: Proper kerneldoc comments for enumeration/removal Rafael J. Wysocki
2014-01-27  0:38 ` [PATCH 2/11] ACPI / hotplug / PCI: Simplify register_slot() Rafael J. Wysocki
2014-01-27  0:39 ` [PATCH 3/11] ACPI / hotplug / PCI: Drop acpiphp_bus_trim() Rafael J. Wysocki
2014-01-27  0:40 ` [PATCH 4/11] ACPI / hotplug / PCI: Rework acpiphp_no_hotplug() Rafael J. Wysocki
2014-01-27  0:41 ` [PATCH 5/11] ACPI / hotplug / PCI: Store acpi_device pointer in acpiphp_context Rafael J. Wysocki
2014-01-27  0:41 ` [PATCH 6/11] ACPI / hotplug / PCI: Drop acpiphp_bus_add() Rafael J. Wysocki
2014-01-27  0:42 ` [PATCH 7/11] ACPI / hotplug / PCI: Drop crit_sect locking Rafael J. Wysocki
2014-01-27  0:43 ` [PATCH 8/11] ACPI / hotplug / PCI: Simplify hotplug_event() Rafael J. Wysocki
2014-01-27  0:44 ` [PATCH 9/11] ACPI / hotplug / PCI: Simplify disable_slot() Rafael J. Wysocki
2014-01-27  0:45 ` [PATCH 10/11] ACPI / hotplug / PCI: Use acpi_handle_debug() in hotplug_event() Rafael J. Wysocki
2014-01-27  0:46 ` [PATCH 11/11] ACPI / hotplug: Do not pass ACPI handles to ACPI dock operations Rafael J. Wysocki
2014-01-28 22:10 ` [PATCH 0/5][RFT] ACPI / hotplug / PCI: Consolidation of ACPIPHP with ACPI core device hotplug Rafael J. Wysocki
2014-01-28 22:12   ` [PATCH 1/5][RFT] ACPI / hotplug / PCI: Attach hotplug contexts to struct acpi_device Rafael J. Wysocki
2014-01-28 22:13   ` [PATCH 2/5][RFT] ACPI / hotplug: Introduce acpi_install_hotplug_notify_handler() Rafael J. Wysocki
2014-01-28 22:14   ` [PATCH 3/5][RFT] ACPI / hotplug / PCI: Consolidate ACPIPHP with ACPI core hotplug Rafael J. Wysocki
2014-01-28 22:14   ` [PATCH 4/5][RFT] ACPI / hotplug / PCI: Simplify acpi_install_hotplug_notify_handler() Rafael J. Wysocki
2014-01-28 22:16   ` [PATCH 5/5][RFT] ACPI / hotplug: Dispach hotplug notifications from acpi_bus_notify() Rafael J. Wysocki
2014-01-28 23:57   ` [PATCH 0/5][RFT] ACPI / hotplug / PCI: Consolidation of ACPIPHP with ACPI core device hotplug Rafael J. Wysocki
2014-01-28 23:58     ` [Resend][PATCH 1/5][RFT] ACPI / hotplug / PCI: Attach hotplug contexts to struct acpi_device Rafael J. Wysocki
2014-01-28 23:59     ` [Resend][PATCH 2/5][RFT] ACPI / hotplug: Introduce acpi_install_hotplug_notify_handler() Rafael J. Wysocki
2014-01-28 23:59     ` [Update][PATCH 3/5][RFT] ACPI / hotplug / PCI: Consolidate ACPIPHP with ACPI core hotplug Rafael J. Wysocki
2014-01-29  0:00     ` [Update][PATCH 4/5][RFT] ACPI / hotplug / PCI: Simplify acpi_install_hotplug_notify_handler() Rafael J. Wysocki
2014-01-31 15:28       ` Mika Westerberg
2014-01-31 15:42         ` Rafael J. Wysocki
2014-01-31 15:40           ` Mika Westerberg
2014-01-31 16:01             ` Mika Westerberg
2014-01-31 16:16               ` Rafael J. Wysocki
2014-01-31 17:09                 ` Mika Westerberg
2014-01-31 17:34                   ` Rafael J. Wysocki
2014-02-02  0:12                     ` Rafael J. Wysocki
2014-01-29  0:02     ` [Update][PATCH 5/5][RFT] ACPI / hotplug / PCI: Hotplug notifications from acpi_bus_notify() Rafael J. Wysocki
2014-01-30 15:28       ` [Update 2x][PATCH " Rafael J. Wysocki
2014-02-02  0:52     ` [PATCH v2 0/6] ACPI / hotplug / PCI: Consolidation of ACPIPHP with ACPI core device hotplug Rafael J. Wysocki
2014-02-02  0:54       ` [PATCH v2 1/6] ACPI / hotplug: Fix theoretical race in acpi_hotplug_notify_cb() Rafael J. Wysocki
2014-02-02 17:01         ` Rafael J. Wysocki
2014-02-02  0:55       ` [PATCH v2 2/6] ACPI / hotplug / PCI: Define hotplug context lock in the core Rafael J. Wysocki
2014-02-02  0:56       ` [PATCH v2 3/6] ACPI / hotplug / PCI: Consolidate ACPIPHP with ACPI core hotplug Rafael J. Wysocki
2014-02-02  0:57       ` [PATCH v2 4/6] ACPI / hotplug / PCI: Rework the handling of eject requests Rafael J. Wysocki
2014-02-02  0:58       ` [PATCH v2 5/6] ACPI / hotplug / PCI: Simplify acpi_install_hotplug_notify_handler() Rafael J. Wysocki
2014-02-02  0:58       ` [PATCH v2 6/6] ACPI / hotplug / PCI: Hotplug notifications from acpi_bus_notify() Rafael J. Wysocki
2014-02-02 17:11       ` [PATCH v3 0/7] ACPI / hotplug / PCI: Consolidation of ACPIPHP with ACPI core device hotplug Rafael J. Wysocki
2014-02-02 17:12         ` [PATCH v3 1/7] ACPICA: Introduce acpi_get_data_full() and rework acpi_get_data() Rafael J. Wysocki
2014-02-02 17:15         ` Rafael J. Wysocki [this message]
2014-02-02 17:16         ` [PATCH v3 3/7] ACPI / hotplug / PCI: Define hotplug context lock in the core Rafael J. Wysocki
2014-02-02 17:17         ` [PATCH v3 4/7] ACPI / hotplug / PCI: Consolidate ACPIPHP with ACPI core hotplug Rafael J. Wysocki
2014-02-02 17:18         ` [PATCH v3 5/7] ACPI / hotplug / PCI: Rework the handling of eject requests Rafael J. Wysocki
2014-02-02 17:19         ` [PATCH v3 6/7] ACPI / hotplug / PCI: Simplify acpi_install_hotplug_notify_handler() Rafael J. Wysocki
2014-02-02 17:20         ` [PATCH v3 7/7] ACPI / hotplug / PCI: Hotplug notifications from acpi_bus_notify() Rafael J. Wysocki
2014-02-03 10:45         ` [PATCH v3 0/7] ACPI / hotplug / PCI: Consolidation of ACPIPHP with ACPI core device hotplug Mika Westerberg
2014-02-03 21:51           ` Rafael J. Wysocki
2014-02-02  0:19 ` [PATCH v2 0/13] ACPI / hotplug / PCI: Updates on top of changes merged recently Rafael J. Wysocki
2014-02-02  0:21   ` [PATCH v2 1/13] ACPI / hotplug / PCI: Remove entries from bus->devices in reverse order Rafael J. Wysocki
2014-02-02  0:22   ` [PATCH v2 2/13] ACPI / hotplug / PCI: Move PCI rescan-remove locking to hotplug_event() Rafael J. Wysocki
2014-02-02  0:23   ` [PATCH v2 3/13] ACPI / hotplug / PCI: Simplify disable_slot() Rafael J. Wysocki
2014-02-02  0:24   ` [PATCH v2 4/13] ACPI / hotplug / PCI: Proper kerneldoc comments for enumeration/removal Rafael J. Wysocki
2014-02-02  0:25   ` [PATCH v2 5/13] ACPI / hotplug / PCI: Simplify register_slot() Rafael J. Wysocki
2014-02-02  0:26   ` [PATCH v2 6/13] ACPI / hotplug / PCI: Drop acpiphp_bus_trim() Rafael J. Wysocki
2014-02-02  0:27   ` [PATCH v2 7/13] ACPI / hotplug / PCI: Rework acpiphp_no_hotplug() Rafael J. Wysocki
2014-02-02  0:27   ` [PATCH v2 8/13] ACPI / hotplug / PCI: Store acpi_device pointer in acpiphp_context Rafael J. Wysocki
2014-02-02  0:28   ` [PATCH v2 9/13] ACPI / hotplug / PCI: Drop acpiphp_bus_add() Rafael J. Wysocki
2014-02-02  0:29   ` [PATCH v2 10/13] ACPI / hotplug / PCI: Drop crit_sect locking Rafael J. Wysocki
2014-02-02  0:30   ` [PATCH v2 11/13] ACPI / hotplug / PCI: Simplify hotplug_event() Rafael J. Wysocki
2014-02-02  0:31   ` [PATCH v2 12/13] ACPI / hotplug / PCI: Use acpi_handle_debug() in hotplug_event() Rafael J. Wysocki
2014-02-02  0:31   ` [PATCH v2 13/13] ACPI / hotplug: Do not pass ACPI handles to ACPI dock operations Rafael J. Wysocki
2014-02-03  1:47   ` [PATCH] ACPI / hotplug / PCI: Scan root bus under the PCI rescan-remove lock Rafael J. Wysocki
2014-02-03 10:44   ` [PATCH v2 0/13] ACPI / hotplug / PCI: Updates on top of changes merged recently Mika Westerberg
2014-02-03 23:12     ` [PATCH v2 0/24] ACPI / hotplug / PCI: ACPIPHP updates and consolidation with ACPI core Rafael J. Wysocki
2014-02-03 23:14       ` [PATCH 1/24][Resend] ACPI / hotplug / PCI: Remove entries from bus->devices in reverse order Rafael J. Wysocki
2014-02-03 23:15       ` [PATCH 2/24][Resend] ACPI / hotplug / PCI: Move PCI rescan-remove locking to hotplug_event() Rafael J. Wysocki
2014-02-03 23:16       ` [PATCH 3/24][Resend] ACPI / hotplug / PCI: Scan root bus under the PCI rescan-remove lock Rafael J. Wysocki
2014-02-03 23:18       ` [PATCH 4/24][New] ACPI / hotplug / PCI: Fix bridge removal race in handle_hotplug_event() Rafael J. Wysocki
2014-02-03 23:18       ` [PATCH 5/24][New] ACPI / hotplug / PCI: Fix bridge removal race vs dock events Rafael J. Wysocki
2014-02-03 23:20       ` [PATCH 6/24][Resend] ACPI / hotplug / PCI: Simplify disable_slot() Rafael J. Wysocki
2014-02-03 23:21       ` [PATCH 7/24][Resend] ACPI / hotplug / PCI: Proper kerneldoc comments for enumeration/removal Rafael J. Wysocki
2014-02-03 23:22       ` [PATCH 8/24][Resend] ACPI / hotplug / PCI: Simplify register_slot() Rafael J. Wysocki
2014-02-03 23:23       ` [PATCH 9/24][Resend] ACPI / hotplug / PCI: Drop acpiphp_bus_trim() Rafael J. Wysocki
2014-02-03 23:24       ` [PATCH 10/24][Resend] ACPI / hotplug / PCI: Rework acpiphp_no_hotplug() Rafael J. Wysocki
2014-02-03 23:25       ` [PATCH 11/24][Update] ACPI / hotplug / PCI: Store acpi_device pointer in acpiphp_context Rafael J. Wysocki
2014-02-03 23:26       ` [PATCH 12/24][Resend] ACPI / hotplug / PCI: Drop acpiphp_bus_add() Rafael J. Wysocki
2014-02-03 23:27       ` [PATCH 13/24][Resend] ACPI / hotplug / PCI: Drop crit_sect locking Rafael J. Wysocki
2014-02-03 23:33       ` [PATCH 14/24][Update] ACPI / hotplug / PCI: Simplify hotplug_event() Rafael J. Wysocki
2014-02-03 23:33       ` [PATCH 15/24][Resend] ACPI / hotplug / PCI: Use acpi_handle_debug() in hotplug_event() Rafael J. Wysocki
2014-02-03 23:34       ` [PATCH 16/24][New] ACPI / hotplug / PCI: Do not pass ACPI handle to hotplug_event() Rafael J. Wysocki
2014-02-03 23:34       ` [PATCH 17/24][Resend] ACPICA: Introduce acpi_get_data_full() and rework acpi_get_data() Rafael J. Wysocki
2014-02-03 23:36       ` [PATCH 18/24][Update] ACPI / hotplug: Fix potential race in acpi_bus_notify() Rafael J. Wysocki
2014-02-03 23:36       ` [PATCH 19/24][Update] ACPI / hotplug / PCI: Define hotplug context lock in the core Rafael J. Wysocki
2014-02-03 23:37       ` [PATCH 20/24][Update] ACPI / hotplug / PCI: Consolidate ACPIPHP with ACPI core hotplug Rafael J. Wysocki
2014-02-06 13:07         ` [Update][PATCH 20/24] " Rafael J. Wysocki
2014-02-06 23:35           ` [Update 2x][PATCH " Rafael J. Wysocki
2014-02-03 23:38       ` [PATCH 21/24][Resend] ACPI / hotplug / PCI: Rework the handling of eject requests Rafael J. Wysocki
2014-02-03 23:39       ` [PATCH 22/24][Resend] ACPI / hotplug / PCI: Simplify acpi_install_hotplug_notify_handler() Rafael J. Wysocki
2014-02-06 13:09         ` [Update][PATCH 22/24] " Rafael J. Wysocki
2014-02-03 23:40       ` [PATCH 23/24][Update] ACPI / hotplug / PCI: Hotplug notifications from acpi_bus_notify() Rafael J. Wysocki
2014-02-06 13:10         ` [Update][PATCH 23/24] " Rafael J. Wysocki
2014-02-03 23:41       ` [PATCH 24/24][New] ACPI / hotplug / PCI: Rework acpiphp_check_host_bridge() Rafael J. Wysocki
2014-02-05 10:14       ` [PATCH v2 0/24] ACPI / hotplug / PCI: ACPIPHP updates and consolidation with ACPI core Mika Westerberg
2014-02-05 10:59         ` Rafael J. Wysocki
2014-02-11  0:19 ` [PATCH 0/11] ACPI / hotplug / PCI: Updates on top of changes merged recently Bjorn Helgaas
2014-02-11 12:53   ` Rafael J. Wysocki

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