This is a note to let you know that I've just added the patch titled
HID: uhid: Use READ_ONCE()/WRITE_ONCE() for ->running
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
hid-uhid-use-read_once-write_once-for-running.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 652f2e382be89b8af0c340397dcd2e03609843ad
Author: Jann Horn <jannh@xxxxxxxxxx>
Date: Fri Jan 14 14:33:31 2022 +0100
HID: uhid: Use READ_ONCE()/WRITE_ONCE() for ->running
[ Upstream commit c8e7ff41f819b0c31c66c5196933c26c18f7681f ]
The flag uhid->running can be set to false by uhid_device_add_worker()
without holding the uhid->devlock. Mark all reads/writes of the flag
that might race with READ_ONCE()/WRITE_ONCE() for clarity and
correctness.
Signed-off-by: Jann Horn <jannh@xxxxxxxxxx>
Signed-off-by: Jiri Kosina <jkosina@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/hid/uhid.c b/drivers/hid/uhid.c
index ba0ca652b9dab..09da654d2b05c 100644
--- a/drivers/hid/uhid.c
+++ b/drivers/hid/uhid.c
@@ -84,7 +84,7 @@ static void uhid_device_add_worker(struct work_struct *work)
* However, we do have to clear the ->running flag and do a
* wakeup to make sure userspace knows that the device is gone.
*/
- uhid->running = false;
+ WRITE_ONCE(uhid->running, false);
wake_up_interruptible(&uhid->report_wait);
}
}
@@ -194,9 +194,9 @@ static int __uhid_report_queue_and_wait(struct uhid_device *uhid,
spin_unlock_irqrestore(&uhid->qlock, flags);
ret = wait_event_interruptible_timeout(uhid->report_wait,
- !uhid->report_running || !uhid->running,
+ !uhid->report_running || !READ_ONCE(uhid->running),
5 * HZ);
- if (!ret || !uhid->running || uhid->report_running)
+ if (!ret || !READ_ONCE(uhid->running) || uhid->report_running)
ret = -EIO;
else if (ret < 0)
ret = -ERESTARTSYS;
@@ -237,7 +237,7 @@ static int uhid_hid_get_report(struct hid_device *hid, unsigned char rnum,
struct uhid_event *ev;
int ret;
- if (!uhid->running)
+ if (!READ_ONCE(uhid->running))
return -EIO;
ev = kzalloc(sizeof(*ev), GFP_KERNEL);
@@ -279,7 +279,7 @@ static int uhid_hid_set_report(struct hid_device *hid, unsigned char rnum,
struct uhid_event *ev;
int ret;
- if (!uhid->running || count > UHID_DATA_MAX)
+ if (!READ_ONCE(uhid->running) || count > UHID_DATA_MAX)
return -EIO;
ev = kzalloc(sizeof(*ev), GFP_KERNEL);
@@ -580,7 +580,7 @@ static int uhid_dev_destroy(struct uhid_device *uhid)
if (!uhid->hid)
return -EINVAL;
- uhid->running = false;
+ WRITE_ONCE(uhid->running, false);
wake_up_interruptible(&uhid->report_wait);
cancel_work_sync(&uhid->worker);
@@ -594,7 +594,7 @@ static int uhid_dev_destroy(struct uhid_device *uhid)
static int uhid_dev_input(struct uhid_device *uhid, struct uhid_event *ev)
{
- if (!uhid->running)
+ if (!READ_ONCE(uhid->running))
return -EINVAL;
hid_input_report(uhid->hid, HID_INPUT_REPORT, ev->u.input.data,
@@ -605,7 +605,7 @@ static int uhid_dev_input(struct uhid_device *uhid, struct uhid_event *ev)
static int uhid_dev_input2(struct uhid_device *uhid, struct uhid_event *ev)
{
- if (!uhid->running)
+ if (!READ_ONCE(uhid->running))
return -EINVAL;
hid_input_report(uhid->hid, HID_INPUT_REPORT, ev->u.input2.data,
@@ -617,7 +617,7 @@ static int uhid_dev_input2(struct uhid_device *uhid, struct uhid_event *ev)
static int uhid_dev_get_report_reply(struct uhid_device *uhid,
struct uhid_event *ev)
{
- if (!uhid->running)
+ if (!READ_ONCE(uhid->running))
return -EINVAL;
uhid_report_wake_up(uhid, ev->u.get_report_reply.id, ev);
@@ -627,7 +627,7 @@ static int uhid_dev_get_report_reply(struct uhid_device *uhid,
static int uhid_dev_set_report_reply(struct uhid_device *uhid,
struct uhid_event *ev)
{
- if (!uhid->running)
+ if (!READ_ONCE(uhid->running))
return -EINVAL;
uhid_report_wake_up(uhid, ev->u.set_report_reply.id, ev);
