On Wed, 19 Dec 2007 16:57:04 +0100
"Remy Bohmer" <[EMAIL PROTECTED]> wrote:
> Hello Haavard,
>
> Sorry.. But I get an Oops on Preempt-RT with the latest set of
> patches. I did not see it earlier today with the other set of patches.
Hmm...from the backtrace, it looks like lock recursion -- port->lock is
held for the whole duration of the tasklet, but we somehow end up in
uart_start(), which grabs the lock again.
Could you try the patch below? It's a bit strange that you got an oops
though...
Haavard
diff --git a/drivers/serial/atmel_serial.c b/drivers/serial/atmel_serial.c
index 7967054..948c643 100644
--- a/drivers/serial/atmel_serial.c
+++ b/drivers/serial/atmel_serial.c
@@ -666,7 +666,13 @@ static void atmel_rx_from_ring(struct uart_port *port)
uart_insert_char(port, status, ATMEL_US_OVRE, c.ch, flg);
}
+ /*
+ * Drop the lock here since it might end up calling
+ * uart_start(), which takes the lock.
+ */
+ spin_unlock(&port->lock);
tty_flip_buffer_push(port->info->tty);
+ spin_lock(&port->lock);
}
static void atmel_rx_from_dma(struct uart_port *port)
--
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