The nwbutton driver uses interruptible_sleep_on to wait for buttons getting pressed after we enter the read() function, which is inherently racy and cannot be fixed by using wait_event without changing the driver's user space interface.
Instead, this patch just uses an open-coded variant of the same interruptible_sleep_on() call, so the driver behavior doesn't change but we remove the sleep_on family from the kernel. Signed-off-by: Arnd Bergmann <[email protected]> Cc: Greg Kroah-Hartman <[email protected]> --- drivers/char/nwbutton.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/char/nwbutton.c b/drivers/char/nwbutton.c index 1fd00dc..76c490f 100644 --- a/drivers/char/nwbutton.c +++ b/drivers/char/nwbutton.c @@ -168,7 +168,10 @@ static irqreturn_t button_handler (int irq, void *dev_id) static int button_read (struct file *filp, char __user *buffer, size_t count, loff_t *ppos) { - interruptible_sleep_on (&button_wait_queue); + DEFINE_WAIT(wait); + prepare_to_wait(&button_wait_queue, &wait, TASK_INTERRUPTIBLE); + schedule(); + finish_wait(&button_wait_queue, &wait); return (copy_to_user (buffer, &button_output_buffer, bcount)) ? -EFAULT : bcount; } -- 1.8.3.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
