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ACPI: fix oops after dock driver fails to initialize

PATCH In review Chuck Ebbert 2 participants 2 messages May 8, 2007 – May 10, 2007 ACPI

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Chuck Ebbert

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#0 lore raw

PATCH 1/1 ACPI: fix oops after dock driver fails to initialize

ACPI: fix oops after dock driver fails to initialize

The driver tests the dock_station pointer for nonnull to check whether it has initialized properly. But in some cases dock_station will be non-null after being freed when driver init fails. Fix by zeroing the pointer after freeing.

Signed-off-by Chuck Ebbert <[email protected]>
---
 drivers/acpi/dock.c |    6 ++++++
 1 file changed, 6 insertions(+)
drivers/acpi/dock.c +6 -0
@@ -698,6 +698,7 @@ static int dock_add(acpi_handle handle)
 	if (ret) {
 		printk(KERN_ERR PREFIX "Error %d registering dock device\n", ret);
 		kfree(dock_station);
+		dock_station = NULL;
 		return ret;
 	}
 	ret = device_create_file(&dock_device.dev, &dev_attr_docked);

@@ -705,6 +706,7 @@ static int dock_add(acpi_handle handle)
 		printk("Error %d adding sysfs file\n", ret);
 		platform_device_unregister(&dock_device);
 		kfree(dock_station);
+		dock_station = NULL;
 		return ret;
 	}
 	ret = device_create_file(&dock_device.dev, &dev_attr_undock);

@@ -713,6 +715,7 @@ static int dock_add(acpi_handle handle)
 		device_remove_file(&dock_device.dev, &dev_attr_docked);
 		platform_device_unregister(&dock_device);
 		kfree(dock_station);
+		dock_station = NULL;
 		return ret;
 	}
 

@@ -725,6 +728,7 @@ static int dock_add(acpi_handle handle)
 	dd = alloc_dock_dependent_device(handle);
 	if (!dd) {
 		kfree(dock_station);
+		dock_station = NULL;
 		ret = -ENOMEM;
 		goto dock_add_err_unregister;
 	}

@@ -752,6 +756,7 @@ dock_add_err_unregister:
 	device_remove_file(&dock_device.dev, &dev_attr_undock);
 	platform_device_unregister(&dock_device);
 	kfree(dock_station);
+	dock_station = NULL;
 	return ret;
 }
 

@@ -785,6 +790,7 @@ static int dock_remove(void)
 
 	/* free dock station memory */
 	kfree(dock_station);
+	dock_station = NULL;
 	return 0;
 }
#1 lore raw
Quoted 1 line · On Tue, 08 May 2007 18:39:55 -0400 Chuck Ebbert <[email protected]> wrote:

You didn't write much.

Oh, it was an attachment. thwap.

Quoted 57 lines

ACPI: fix oops after dock driver fails to initialize

The driver tests the dock_station pointer for nonnull to check whether it has initialized properly. But in some cases dock_station will be non-null after being freed when driver init fails. Fix by zeroing the pointer after freeing.

Signed-off-by Chuck Ebbert <[email protected]>
---
 drivers/acpi/dock.c |    6 ++++++
 1 file changed, 6 insertions(+)
drivers/acpi/dock.c +5 -0
@@ -698,6 +698,7 @@ static int dock_add(acpi_handle handle)
 	if (ret) {
 		printk(KERN_ERR PREFIX "Error %d registering dock device\n", ret);
 		kfree(dock_station);
+		dock_station = NULL;
 		return ret;
 	}
 	ret = device_create_file(&dock_device.dev, &dev_attr_docked);

@@ -705,6 +706,7 @@ static int dock_add(acpi_handle handle)
 		printk("Error %d adding sysfs file\n", ret);
 		platform_device_unregister(&dock_device);
 		kfree(dock_station);
+		dock_station = NULL;
 		return ret;
 	}
 	ret = device_create_file(&dock_device.dev, &dev_attr_undock);

@@ -713,6 +715,7 @@ static int dock_add(acpi_handle handle)
 		device_remove_file(&dock_device.dev, &dev_attr_docked);
 		platform_device_unregister(&dock_device);
 		kfree(dock_station);
+		dock_station = NULL;
 		return ret;
 	}
 

@@ -725,6 +728,7 @@ static int dock_add(acpi_handle handle)
 	dd = alloc_dock_dependent_device(handle);
 	if (!dd) {
 		kfree(dock_station);
+		dock_station = NULL;
 		ret = -ENOMEM;
 		goto dock_add_err_unregister;
 	}

@@ -752,6 +756,7 @@ dock_add_err_unregister:
 	device_remove_file(&dock_device.dev, &dev_attr_undock);
 	platform_device_unregister(&dock_device);
 	kfree(dock_station);
+	dock_station = NULL;
 	return ret;
 }

drivers/acpi/dock.c static int dock_remove(void) · line 796

Quoted 7 lines
drivers/acpi/dock.c +1 -0
@@ -785,6 +790,7 @@ static int dock_remove(void)
 
 	/* free dock station memory */
 	kfree(dock_station);
+	dock_station = NULL;
 	return 0;
 }

I think you're missing a case, here:

	ret = device_create_file(&dock_device.dev, &dev_attr_uid);
	if (ret) {
		printk("Error %d adding sysfs file\n", ret);
		platform_device_unregister(&dock_device);
		kfree(dock_station);
		return ret;
	}

also, the code duplication in there is unpleasing. Doesn't this look better?

 drivers/acpi/dock.c |   26 ++++++++++++--------------
 1 files changed, 12 insertions(+), 14 deletions(-)
drivers/acpi/dock.c renamed from drivers/acpi/dock.c~acpi-fix-oops-after-dock-driver-fails-to-initialize +12 -14
diff -puN drivers/acpi/dock.c~acpi-fix-oops-after-dock-driver-fails-to-initialize drivers/acpi/dock.c
@@ -714,31 +714,24 @@ static int dock_add(acpi_handle handle)
 	dock_device.name = dock_device_name;
 	ret = platform_device_register(&dock_device);
 	if (ret) {
-		printk(KERN_ERR PREFIX "Error %d registering dock device\n", ret);
-		kfree(dock_station);
-		return ret;
+		printk(KERN_ERR PREFIX "Error %d registering dock device\n",
+				ret);
+		goto err;
 	}
 	ret = device_create_file(&dock_device.dev, &dev_attr_docked);
 	if (ret) {
 		printk("Error %d adding sysfs file\n", ret);
-		platform_device_unregister(&dock_device);
-		kfree(dock_station);
-		return ret;
+		goto err_register;
 	}
 	ret = device_create_file(&dock_device.dev, &dev_attr_undock);
 	if (ret) {
 		printk("Error %d adding sysfs file\n", ret);
-		device_remove_file(&dock_device.dev, &dev_attr_docked);
-		platform_device_unregister(&dock_device);
-		kfree(dock_station);
-		return ret;
+		goto err_sysfs_1;
 	}
 	ret = device_create_file(&dock_device.dev, &dev_attr_uid);
 	if (ret) {
 		printk("Error %d adding sysfs file\n", ret);
-		platform_device_unregister(&dock_device);
-		kfree(dock_station);
-		return ret;
+		goto err_sysfs_2;
 	}
 
 	/* Find dependent devices */

@@ -749,7 +742,6 @@ static int dock_add(acpi_handle handle)
 	/* add the dock station as a device dependent on itself */
 	dd = alloc_dock_dependent_device(handle);
 	if (!dd) {
-		kfree(dock_station);
 		ret = -ENOMEM;
 		goto dock_add_err_unregister;
 	}

@@ -773,10 +765,15 @@ static int dock_add(acpi_handle handle)
 dock_add_err:
 	kfree(dd);
 dock_add_err_unregister:
+err_sysfs_2:
 	device_remove_file(&dock_device.dev, &dev_attr_docked);
+err_sysfs_1:
 	device_remove_file(&dock_device.dev, &dev_attr_undock);
+err_register:
 	platform_device_unregister(&dock_device);
+err:
 	kfree(dock_station);
+	dock_station = NULL;
 	return ret;
 }
 

@@ -810,6 +807,7 @@ static int dock_remove(void)
 
 	/* free dock station memory */
 	kfree(dock_station);
+	dock_station = NULL;
 	return 0;
 }

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