When the a large chunk of data send and the receiver does not send a Flow Control frame back in time, the sendmsg() does not return a error code, but the number of bytes sent corresponding to the size of the packet. If a timeout occurs the isotp_tx_timer_handler() is fired, sets sk->sk_err and calls the sk->sk_error_report() function. It was wrongly expected that the error would be propagated to user space in every case. For isotp_sendmsg() blocking on wait_event_interruptible() this is not the case. This patch fixes the problem by checking if sk->sk_err is set and returning the error to user space. Link: https://github.com/hartkopp/can-isotp/issues/42 Link: https://github.com/hartkopp/can-isotp/pull/43 Cc: Oliver Hartkopp <socketcan@xxxxxxxxxxxx> Cc: Sottas Guillaume (LMB) <Guillaume.Sottas@xxxxxxxxxxxx> Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx> --- Changes since v1: - add proper patch descriptiom - return negative error value net/can/isotp.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/can/isotp.c b/net/can/isotp.c index 9f94ad3caee9..d2601717211d 100644 --- a/net/can/isotp.c +++ b/net/can/isotp.c @@ -954,6 +954,9 @@ static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size) if (wait_tx_done) { /* wait for complete transmission of current pdu */ wait_event_interruptible(so->wait, so->tx.state == ISOTP_IDLE); + + if (sk->sk_err) + return -sk->sk_err; } return size; -- 2.30.2
