[3.8.y.z extended stable] Patch "Input: mousedev - fix race when creating mixed device" has been added to staging queue
Kamal Mostafa
kamal at canonical.com
Mon Mar 31 18:48:12 UTC 2014
This is a note to let you know that I have just added a patch titled
Input: mousedev - fix race when creating mixed device
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 3.8.13.21.
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 cec5d1e4d58b41b97ca9c39fd6f1bcdb0b5b9255 Mon Sep 17 00:00:00 2001
From: Dmitry Torokhov <dmitry.torokhov at gmail.com>
Date: Thu, 6 Mar 2014 12:57:24 -0800
Subject: Input: mousedev - fix race when creating mixed device
commit e4dbedc7eac7da9db363a36f2bd4366962eeefcc upstream.
We should not be using static variable mousedev_mix in methods that can be
called before that singleton gets assigned. While at it let's add open and
close methods to mousedev structure so that we do not need to test if we
are dealing with multiplexor or normal device and simply call appropriate
method directly.
This fixes: https://bugzilla.kernel.org/show_bug.cgi?id=71551
Reported-by: GiulioDP <depasquale.giulio at gmail.com>
Tested-by: GiulioDP <depasquale.giulio at gmail.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov at gmail.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
drivers/input/mousedev.c | 73 ++++++++++++++++++++++++++++--------------------
1 file changed, 42 insertions(+), 31 deletions(-)
diff --git a/drivers/input/mousedev.c b/drivers/input/mousedev.c
index 4c842c3..b604564 100644
--- a/drivers/input/mousedev.c
+++ b/drivers/input/mousedev.c
@@ -67,7 +67,6 @@ struct mousedev {
struct device dev;
struct cdev cdev;
bool exist;
- bool is_mixdev;
struct list_head mixdev_node;
bool opened_by_mixdev;
@@ -77,6 +76,9 @@ struct mousedev {
int old_x[4], old_y[4];
int frac_dx, frac_dy;
unsigned long touch;
+
+ int (*open_device)(struct mousedev *mousedev);
+ void (*close_device)(struct mousedev *mousedev);
};
enum mousedev_emul {
@@ -116,9 +118,6 @@ static unsigned char mousedev_imex_seq[] = { 0xf3, 200, 0xf3, 200, 0xf3, 80 };
static struct mousedev *mousedev_mix;
static LIST_HEAD(mousedev_mix_list);
-static void mixdev_open_devices(void);
-static void mixdev_close_devices(void);
-
#define fx(i) (mousedev->old_x[(mousedev->pkt_count - (i)) & 03])
#define fy(i) (mousedev->old_y[(mousedev->pkt_count - (i)) & 03])
@@ -428,9 +427,7 @@ static int mousedev_open_device(struct mousedev *mousedev)
if (retval)
return retval;
- if (mousedev->is_mixdev)
- mixdev_open_devices();
- else if (!mousedev->exist)
+ if (!mousedev->exist)
retval = -ENODEV;
else if (!mousedev->open++) {
retval = input_open_device(&mousedev->handle);
@@ -446,9 +443,7 @@ static void mousedev_close_device(struct mousedev *mousedev)
{
mutex_lock(&mousedev->mutex);
- if (mousedev->is_mixdev)
- mixdev_close_devices();
- else if (mousedev->exist && !--mousedev->open)
+ if (mousedev->exist && !--mousedev->open)
input_close_device(&mousedev->handle);
mutex_unlock(&mousedev->mutex);
@@ -459,21 +454,29 @@ static void mousedev_close_device(struct mousedev *mousedev)
* stream. Note that this function is called with mousedev_mix->mutex
* held.
*/
-static void mixdev_open_devices(void)
+static int mixdev_open_devices(struct mousedev *mixdev)
{
- struct mousedev *mousedev;
+ int error;
+
+ error = mutex_lock_interruptible(&mixdev->mutex);
+ if (error)
+ return error;
- if (mousedev_mix->open++)
- return;
+ if (!mixdev->open++) {
+ struct mousedev *mousedev;
- list_for_each_entry(mousedev, &mousedev_mix_list, mixdev_node) {
- if (!mousedev->opened_by_mixdev) {
- if (mousedev_open_device(mousedev))
- continue;
+ list_for_each_entry(mousedev, &mousedev_mix_list, mixdev_node) {
+ if (!mousedev->opened_by_mixdev) {
+ if (mousedev_open_device(mousedev))
+ continue;
- mousedev->opened_by_mixdev = true;
+ mousedev->opened_by_mixdev = true;
+ }
}
}
+
+ mutex_unlock(&mixdev->mutex);
+ return 0;
}
/*
@@ -481,19 +484,22 @@ static void mixdev_open_devices(void)
* device. Note that this function is called with mousedev_mix->mutex
* held.
*/
-static void mixdev_close_devices(void)
+static void mixdev_close_devices(struct mousedev *mixdev)
{
- struct mousedev *mousedev;
+ mutex_lock(&mixdev->mutex);
- if (--mousedev_mix->open)
- return;
+ if (!--mixdev->open) {
+ struct mousedev *mousedev;
- list_for_each_entry(mousedev, &mousedev_mix_list, mixdev_node) {
- if (mousedev->opened_by_mixdev) {
- mousedev->opened_by_mixdev = false;
- mousedev_close_device(mousedev);
+ list_for_each_entry(mousedev, &mousedev_mix_list, mixdev_node) {
+ if (mousedev->opened_by_mixdev) {
+ mousedev->opened_by_mixdev = false;
+ mousedev_close_device(mousedev);
+ }
}
}
+
+ mutex_unlock(&mixdev->mutex);
}
@@ -522,7 +528,7 @@ static int mousedev_release(struct inode *inode, struct file *file)
mousedev_detach_client(mousedev, client);
kfree(client);
- mousedev_close_device(mousedev);
+ mousedev->close_device(mousedev);
return 0;
}
@@ -550,7 +556,7 @@ static int mousedev_open(struct inode *inode, struct file *file)
client->mousedev = mousedev;
mousedev_attach_client(mousedev, client);
- error = mousedev_open_device(mousedev);
+ error = mousedev->open_device(mousedev);
if (error)
goto err_free_client;
@@ -861,16 +867,21 @@ static struct mousedev *mousedev_create(struct input_dev *dev,
if (mixdev) {
dev_set_name(&mousedev->dev, "mice");
+
+ mousedev->open_device = mixdev_open_devices;
+ mousedev->close_device = mixdev_close_devices;
} else {
int dev_no = minor;
/* Normalize device number if it falls into legacy range */
if (dev_no < MOUSEDEV_MINOR_BASE + MOUSEDEV_MINORS)
dev_no -= MOUSEDEV_MINOR_BASE;
dev_set_name(&mousedev->dev, "mouse%d", dev_no);
+
+ mousedev->open_device = mousedev_open_device;
+ mousedev->close_device = mousedev_close_device;
}
mousedev->exist = true;
- mousedev->is_mixdev = mixdev;
mousedev->handle.dev = input_get_device(dev);
mousedev->handle.name = dev_name(&mousedev->dev);
mousedev->handle.handler = handler;
@@ -919,7 +930,7 @@ static void mousedev_destroy(struct mousedev *mousedev)
device_del(&mousedev->dev);
mousedev_cleanup(mousedev);
input_free_minor(MINOR(mousedev->dev.devt));
- if (!mousedev->is_mixdev)
+ if (mousedev != mousedev_mix)
input_unregister_handle(&mousedev->handle);
put_device(&mousedev->dev);
}
--
1.8.3.2
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