4.14-stable review patch. If anyone has any objections, please let me know.
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From: Johan Hovold johan@kernel.org
[ Upstream commit fd00cf81a9a84776ba58e56bd042c726dcf75cf3 ]
The receive_buf callback is supposed to return the number of bytes processed and should specifically not return a negative errno.
Due to missing sanity checks in the serdev tty-port controller, a driver not providing a receive_buf callback could cause the flush_to_ldisc() worker to spin in a tight loop when the tty buffer pointers are incremented with -EINVAL (-22).
The missing sanity checks have now been added to the tty-port controller, but let's fix up the serdev-controller helper as well.
Signed-off-by: Johan Hovold johan@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin alexander.levin@verizon.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- include/linux/serdev.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/include/linux/serdev.h +++ b/include/linux/serdev.h @@ -184,7 +184,7 @@ static inline int serdev_controller_rece struct serdev_device *serdev = ctrl->serdev;
if (!serdev || !serdev->ops->receive_buf) - return -EINVAL; + return 0;
return serdev->ops->receive_buf(serdev, data, count); }