We need to release the port lock when we call tty_flip_buffer_push() to avoid a deadlock when the serial-core routines try to acquire the same lock. This deadlock has been observed on CONFIG_PREEMPT_RT configurations. Signed-off-by: Dale Farnsworth <dale@xxxxxxxxxxxxxx> Cc: <mgreer@xxxxxxxxxx> --- drivers/serial/mpsc.c | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-) diff --git a/drivers/serial/mpsc.c b/drivers/serial/mpsc.c index c9f53e7..158d748 100644 --- a/drivers/serial/mpsc.c +++ b/drivers/serial/mpsc.c @@ -1065,7 +1065,9 @@ next_frame: if ((readl(pi->sdma_base + SDMA_SDCM) & SDMA_SDCM_ERD) == 0) mpsc_start_rx(pi); + spin_unlock(&pi->port.lock); tty_flip_buffer_push(tty); + spin_lock(&pi->port.lock); return rc; } -- 1.5.6 -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
