From cdcb44e87bedcf5070eece61f89f9373a3810031 Mon Sep 17 00:00:00 2001 From: Jiri Kosina Date: Thu, 10 May 2007 08:45:56 +0200 Subject: USB HID: hiddev - fix race between hiddev_send_event() and hiddev_release() There is a small race window in which hiddev_release() could corrupt the list that is being processed for new event in hiddev_send_event(). Synchronize the operations over this list. Signed-off-by: Jiri Kosina --- drivers/hid/usbhid/hiddev.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) (limited to 'drivers/hid') diff --git a/drivers/hid/usbhid/hiddev.c b/drivers/hid/usbhid/hiddev.c index a8b3d66cd49..488d61bdbf2 100644 --- a/drivers/hid/usbhid/hiddev.c +++ b/drivers/hid/usbhid/hiddev.c @@ -51,6 +51,7 @@ struct hiddev { wait_queue_head_t wait; struct hid_device *hid; struct list_head list; + spinlock_t list_lock; }; struct hiddev_list { @@ -161,7 +162,9 @@ static void hiddev_send_event(struct hid_device *hid, { struct hiddev *hiddev = hid->hiddev; struct hiddev_list *list; + unsigned long flags; + spin_lock_irqsave(&hiddev->list_lock, flags); list_for_each_entry(list, &hiddev->list, node) { if (uref->field_index != HID_FIELD_INDEX_NONE || (list->flags & HIDDEV_FLAG_REPORT) != 0) { @@ -171,6 +174,7 @@ static void hiddev_send_event(struct hid_device *hid, kill_fasync(&list->fasync, SIGIO, POLL_IN); } } + spin_unlock_irqrestore(&hiddev->list_lock, flags); wake_up_interruptible(&hiddev->wait); } @@ -235,9 +239,13 @@ static int hiddev_fasync(int fd, struct file *file, int on) static int hiddev_release(struct inode * inode, struct file * file) { struct hiddev_list *list = file->private_data; + unsigned long flags; hiddev_fasync(-1, file, 0); + + spin_lock_irqsave(&list->hiddev->list_lock, flags); list_del(&list->node); + spin_unlock_irqrestore(&list->hiddev->list_lock, flags); if (!--list->hiddev->open) { if (list->hiddev->exist) @@ -257,6 +265,7 @@ static int hiddev_release(struct inode * inode, struct file * file) static int hiddev_open(struct inode *inode, struct file *file) { struct hiddev_list *list; + unsigned long flags; int i = iminor(inode) - HIDDEV_MINOR_BASE; @@ -267,7 +276,11 @@ static int hiddev_open(struct inode *inode, struct file *file) return -ENOMEM; list->hiddev = hiddev_table[i]; + + spin_lock_irqsave(&list->hiddev->list_lock, flags); list_add_tail(&list->node, &hiddev_table[i]->list); + spin_unlock_irqrestore(&list->hiddev->list_lock, flags); + file->private_data = list; if (!list->hiddev->open++) @@ -773,6 +786,7 @@ int hiddev_connect(struct hid_device *hid) init_waitqueue_head(&hiddev->wait); INIT_LIST_HEAD(&hiddev->list); + spin_lock_init(&hiddev->list_lock); hiddev->hid = hid; hiddev->exist = 1; -- cgit v1.2.3