This is a note to let you know that I've just added the patch titled staging: comedi: comedi_fops: do not call blocking ops when !TASK_RUNNING to the 4.12-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: staging-comedi-comedi_fops-do-not-call-blocking-ops-when-task_running.patch and it can be found in the queue-4.12 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From cef988642cdac44e910a27cb6e8166c96f86a0df Mon Sep 17 00:00:00 2001 From: Ian Abbott <abbotti@xxxxxxxxx> Date: Fri, 28 Jul 2017 16:22:31 +0100 Subject: staging: comedi: comedi_fops: do not call blocking ops when !TASK_RUNNING From: Ian Abbott <abbotti@xxxxxxxxx> commit cef988642cdac44e910a27cb6e8166c96f86a0df upstream. Comedi's read and write file operation handlers (`comedi_read()` and `comedi_write()`) currently call `copy_to_user()` or `copy_from_user()` whilst in the `TASK_INTERRUPTIBLE` state, which falls foul of the `might_fault()` checks when enabled. Fix it by setting the current task state back to `TASK_RUNNING` a bit earlier before calling these functions. Reported-by: Piotr Gregor <piotrgregor@xxxxxxxxxxx> Signed-off-by: Ian Abbott <abbotti@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/staging/comedi/comedi_fops.c | 3 +++ 1 file changed, 3 insertions(+) --- a/drivers/staging/comedi/comedi_fops.c +++ b/drivers/staging/comedi/comedi_fops.c @@ -2396,6 +2396,7 @@ static ssize_t comedi_write(struct file continue; } + set_current_state(TASK_RUNNING); wp = async->buf_write_ptr; n1 = min(n, async->prealloc_bufsz - wp); n2 = n - n1; @@ -2528,6 +2529,8 @@ static ssize_t comedi_read(struct file * } continue; } + + set_current_state(TASK_RUNNING); rp = async->buf_read_ptr; n1 = min(n, async->prealloc_bufsz - rp); n2 = n - n1; Patches currently in stable-queue which might be from abbotti@xxxxxxxxx are queue-4.12/staging-comedi-comedi_fops-do-not-call-blocking-ops-when-task_running.patch