* re: ACPI / scan: Simplify acpi_match_device()
@ 2015-04-13 19:21 Dan Carpenter
2015-04-13 19:59 ` Rafael J. Wysocki
0 siblings, 1 reply; 3+ messages in thread
From: Dan Carpenter @ 2015-04-13 19:21 UTC (permalink / raw)
To: rafael.j.wysocki; +Cc: linux-acpi
Hello Rafael J. Wysocki,
The patch e1acdeb0e770: "ACPI / scan: Simplify acpi_match_device()"
from Apr 10, 2015, leads to the following static checker warning:
drivers/acpi/scan.c:269 acpi_companion_match()
error: potential NULL dereference 'adev'.
drivers/acpi/scan.c
247 static struct acpi_device *acpi_companion_match(const struct device *dev)
248 {
249 struct acpi_device *adev;
250
251 adev = ACPI_COMPANION(dev);
252 if (!adev)
253 return NULL;
254
255 if (list_empty(&adev->pnp.ids))
256 return NULL;
257
258 mutex_lock(&adev->physical_node_lock);
259 if (list_empty(&adev->physical_node_list)) {
260 adev = NULL;
^^^^^^^^^^^
261 } else {
262 const struct acpi_device_physical_node *node;
263
264 node = list_first_entry(&adev->physical_node_list,
265 struct acpi_device_physical_node, node);
266 if (node->dev != dev)
267 adev = NULL;
^^^^^^^^^^^^
268 }
269 mutex_unlock(&adev->physical_node_lock);
^^^^^^
Dereference.
270
271 return adev;
272 }
regards,
dan carpenter
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: ACPI / scan: Simplify acpi_match_device()
2015-04-13 19:21 ACPI / scan: Simplify acpi_match_device() Dan Carpenter
@ 2015-04-13 19:59 ` Rafael J. Wysocki
2015-04-14 10:37 ` Mika Westerberg
0 siblings, 1 reply; 3+ messages in thread
From: Rafael J. Wysocki @ 2015-04-13 19:59 UTC (permalink / raw)
To: Dan Carpenter; +Cc: rafael.j.wysocki, linux-acpi, Mika Westerberg
On Monday, April 13, 2015 10:21:59 PM Dan Carpenter wrote:
> Hello Rafael J. Wysocki,
>
> The patch e1acdeb0e770: "ACPI / scan: Simplify acpi_match_device()"
> from Apr 10, 2015, leads to the following static checker warning:
>
> drivers/acpi/scan.c:269 acpi_companion_match()
> error: potential NULL dereference 'adev'.
>
> drivers/acpi/scan.c
> 247 static struct acpi_device *acpi_companion_match(const struct device *dev)
> 248 {
> 249 struct acpi_device *adev;
> 250
> 251 adev = ACPI_COMPANION(dev);
> 252 if (!adev)
> 253 return NULL;
> 254
> 255 if (list_empty(&adev->pnp.ids))
> 256 return NULL;
> 257
> 258 mutex_lock(&adev->physical_node_lock);
> 259 if (list_empty(&adev->physical_node_list)) {
> 260 adev = NULL;
> ^^^^^^^^^^^
> 261 } else {
> 262 const struct acpi_device_physical_node *node;
> 263
> 264 node = list_first_entry(&adev->physical_node_list,
> 265 struct acpi_device_physical_node, node);
> 266 if (node->dev != dev)
> 267 adev = NULL;
> ^^^^^^^^^^^^
> 268 }
> 269 mutex_unlock(&adev->physical_node_lock);
> ^^^^^^
> Dereference.
>
> 270
> 271 return adev;
> 272 }
Right, thanks.
The patch below should fix it.
---
From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Subject: ACPI / scan: Fix NULL pointer dereference in acpi_companion_match()
Commit e1acdeb0e770 "ACPI / scan: Simplify acpi_match_device()"
introduced code that may lead to a NULL pointer dereference when
trying to unlock a mutex. Fix that.
Fixes: e1acdeb0e770 "ACPI / scan: Simplify acpi_match_device()"
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
drivers/acpi/scan.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
Index: linux-pm/drivers/acpi/scan.c
===================================================================
--- linux-pm.orig/drivers/acpi/scan.c
+++ linux-pm/drivers/acpi/scan.c
@@ -247,6 +247,7 @@ static int create_of_modalias(struct acp
static struct acpi_device *acpi_companion_match(const struct device *dev)
{
struct acpi_device *adev;
+ struct mutex *physical_node_lock;
adev = ACPI_COMPANION(dev);
if (!adev)
@@ -255,7 +256,8 @@ static struct acpi_device *acpi_companio
if (list_empty(&adev->pnp.ids))
return NULL;
- mutex_lock(&adev->physical_node_lock);
+ physical_node_lock = &adev->physical_node_lock;
+ mutex_lock(physical_node_lock);
if (list_empty(&adev->physical_node_list)) {
adev = NULL;
} else {
@@ -266,7 +268,7 @@ static struct acpi_device *acpi_companio
if (node->dev != dev)
adev = NULL;
}
- mutex_unlock(&adev->physical_node_lock);
+ mutex_unlock(physical_node_lock);
return adev;
}
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: ACPI / scan: Simplify acpi_match_device()
2015-04-13 19:59 ` Rafael J. Wysocki
@ 2015-04-14 10:37 ` Mika Westerberg
0 siblings, 0 replies; 3+ messages in thread
From: Mika Westerberg @ 2015-04-14 10:37 UTC (permalink / raw)
To: Rafael J. Wysocki; +Cc: Dan Carpenter, rafael.j.wysocki, linux-acpi
On Mon, Apr 13, 2015 at 09:59:48PM +0200, Rafael J. Wysocki wrote:
> On Monday, April 13, 2015 10:21:59 PM Dan Carpenter wrote:
> > Hello Rafael J. Wysocki,
> >
> > The patch e1acdeb0e770: "ACPI / scan: Simplify acpi_match_device()"
> > from Apr 10, 2015, leads to the following static checker warning:
> >
> > drivers/acpi/scan.c:269 acpi_companion_match()
> > error: potential NULL dereference 'adev'.
> >
> > drivers/acpi/scan.c
> > 247 static struct acpi_device *acpi_companion_match(const struct device *dev)
> > 248 {
> > 249 struct acpi_device *adev;
> > 250
> > 251 adev = ACPI_COMPANION(dev);
> > 252 if (!adev)
> > 253 return NULL;
> > 254
> > 255 if (list_empty(&adev->pnp.ids))
> > 256 return NULL;
> > 257
> > 258 mutex_lock(&adev->physical_node_lock);
> > 259 if (list_empty(&adev->physical_node_list)) {
> > 260 adev = NULL;
> > ^^^^^^^^^^^
> > 261 } else {
> > 262 const struct acpi_device_physical_node *node;
> > 263
> > 264 node = list_first_entry(&adev->physical_node_list,
> > 265 struct acpi_device_physical_node, node);
> > 266 if (node->dev != dev)
> > 267 adev = NULL;
> > ^^^^^^^^^^^^
> > 268 }
> > 269 mutex_unlock(&adev->physical_node_lock);
> > ^^^^^^
> > Dereference.
> >
> > 270
> > 271 return adev;
> > 272 }
>
> Right, thanks.
>
> The patch below should fix it.
>
> ---
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> Subject: ACPI / scan: Fix NULL pointer dereference in acpi_companion_match()
>
> Commit e1acdeb0e770 "ACPI / scan: Simplify acpi_match_device()"
> introduced code that may lead to a NULL pointer dereference when
> trying to unlock a mutex. Fix that.
>
> Fixes: e1acdeb0e770 "ACPI / scan: Simplify acpi_match_device()"
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
^ permalink raw reply [flat|nested] 3+ messages in thread
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2015-04-13 19:21 ACPI / scan: Simplify acpi_match_device() Dan Carpenter
2015-04-13 19:59 ` Rafael J. Wysocki
2015-04-14 10:37 ` Mika Westerberg
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