On Wed, 17 Apr 2013, Benjamin Tissoires wrote: > Hi Jiri, > > This is a small rework of the HID debugfs. > I encountered a problem with multitouch devices: they have too much usages to > fit into the fixed size output buffer of 512. > So I digg a little, and end up with those 4 patches.
Hi Benjamin, thanks, I will look into it and see whether I would be able to apply it still for 3.10 merge window. I also have a locking fix for HID-debugfs which I am going to apply shortly, but I am travelling this week, so I am in a bit degraded mode. For reference, locking fix below. From: Jiri Kosina <[email protected]> Subject: [PATCH] HID: protect hid_debug_list Accesses to hid_device->hid_debug_list are not serialized properly, which could result in SMP concurrency issues when HID debugfs events are accessesed by multiple userspace processess. Serialize all the list operations by a mutex. Reported-by: Al Viro <[email protected]> Signed-off-by: Jiri Kosina <[email protected]> --- drivers/hid/hid-core.c | 1 + drivers/hid/hid-debug.c | 6 ++++++ include/linux/hid.h | 1 + 3 files changed, 8 insertions(+) diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c index 1129f49..e3b7123 100644 --- a/drivers/hid/hid-core.c +++ b/drivers/hid/hid-core.c @@ -2347,6 +2347,7 @@ struct hid_device *hid_allocate_device(void) init_waitqueue_head(&hdev->debug_wait); INIT_LIST_HEAD(&hdev->debug_list); + mutex_init(&hdev->debug_list_lock); sema_init(&hdev->driver_lock, 1); sema_init(&hdev->driver_input_lock, 1); diff --git a/drivers/hid/hid-debug.c b/drivers/hid/hid-debug.c index 933fff0..3337261 100644 --- a/drivers/hid/hid-debug.c +++ b/drivers/hid/hid-debug.c @@ -580,12 +580,14 @@ void hid_debug_event(struct hid_device *hdev, char *buf) int i; struct hid_debug_list *list; + mutex_lock(&hdev->debug_list_lock); list_for_each_entry(list, &hdev->debug_list, node) { for (i = 0; i < strlen(buf); i++) list->hid_debug_buf[(list->tail + i) % HID_DEBUG_BUFSIZE] = buf[i]; list->tail = (list->tail + i) % HID_DEBUG_BUFSIZE; } + mutex_unlock(&hdev->debug_list_lock); wake_up_interruptible(&hdev->debug_wait); } @@ -960,7 +962,9 @@ static int hid_debug_events_open(struct inode *inode, struct file *file) file->private_data = list; mutex_init(&list->read_mutex); + mutex_lock(&list->hdev->debug_list_lock); list_add_tail(&list->node, &list->hdev->debug_list); + mutex_unlock(&list->hdev->debug_list_lock); out: return err; @@ -1055,7 +1059,9 @@ static int hid_debug_events_release(struct inode *inode, struct file *file) { struct hid_debug_list *list = file->private_data; + mutex_lock(&list->hdev->debug_list_lock); list_del(&list->node); + mutex_unlock(&list->hdev->debug_list_lock); kfree(list->hid_debug_buf); kfree(list); diff --git a/include/linux/hid.h b/include/linux/hid.h index b7b5ff2..af1b86d 100644 --- a/include/linux/hid.h +++ b/include/linux/hid.h @@ -515,6 +515,7 @@ struct hid_device { /* device report descriptor */ struct dentry *debug_rdesc; struct dentry *debug_events; struct list_head debug_list; + struct mutex debug_list_lock; wait_queue_head_t debug_wait; }; -- Jiri Kosina SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
