From: Ian Abbott Date: Fri, 28 Jul 2017 15:22:31 +0000 (+0100) Subject: staging: comedi: comedi_fops: do not call blocking ops when !TASK_RUNNING X-Git-Tag: v4.9.44~17 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=b189f8eb27153daaaa464d7bfec9c5a8ed2989a0;p=platform%2Fkernel%2Flinux-amlogic.git staging: comedi: comedi_fops: do not call blocking ops when !TASK_RUNNING 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 Signed-off-by: Ian Abbott Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c index ec99790..7458df4 100644 --- a/drivers/staging/comedi/comedi_fops.c +++ b/drivers/staging/comedi/comedi_fops.c @@ -2385,6 +2385,7 @@ static ssize_t comedi_write(struct file *file, const char __user *buf, continue; } + set_current_state(TASK_RUNNING); wp = async->buf_write_ptr; n1 = min(n, async->prealloc_bufsz - wp); n2 = n - n1; @@ -2517,6 +2518,8 @@ static ssize_t comedi_read(struct file *file, char __user *buf, size_t nbytes, } continue; } + + set_current_state(TASK_RUNNING); rp = async->buf_read_ptr; n1 = min(n, async->prealloc_bufsz - rp); n2 = n - n1;