From: Paul Fulghum <paulkf@microgate.com>
To: Tim_T_Murphy@Dell.com
Cc: linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [BUG][2.6.8.1] serial driver hangs SMP kernel, but not the UP kernel
Date: Fri, 29 Oct 2004 16:08:37 -0500 [thread overview]
Message-ID: <1099084117.3356.7.camel@deimos.microgate.com> (raw)
In-Reply-To: <4B0A1C17AA88F94289B0704CFABEF1AB0B4CC4@ausx2kmps304.aus.amer.dell.com>
On Fri, 2004-10-29 at 14:55, Tim_T_Murphy@Dell.com wrote:
> Oct 29 13:34:48 racjag-1 chat[3886]: expect (CLIENTSERVER)
> Oct 29 13:34:48 racjag-1 kernel: drivers/serial/serial_core.c:102: spin_lock(drivers/serial/serial_core.c:023f2548) already locked by drivers/serial/8250.c/1015
> Oct 29 13:34:48 racjag-1 kernel: drivers/serial/8250.c:1017: spin_unlock(drivers/serial/serial_core.c:023f2548) not locked
> Oct 29 13:34:48 racjag-1 chat[3886]: CLIENTSERVER
One way this can happen is a receive interrupt:
serial8250_interrupt();
spin_lock(port->lock);
serial8250_handle_port();
receive_chars();
flip.work.func(); /* if FLIP buffer full */
ldisc->receive_buf(); /* N_TTY */
tty->driver->flush_chars();
uart_start();
spin_lock(port->lock); *BANG*
Try the attached patch and report what happens.
--
Paul Fulghum
paulkf@microgate.com
--- linux-2.6.8/drivers/serial/8250.c 2004-08-14 00:36:13.000000000 -0500
+++ b/drivers/serial/8250.c 2004-10-29 15:58:28.076014336 -0500
@@ -830,9 +830,13 @@ receive_chars(struct uart_8250_port *up,
do {
if (unlikely(tty->flip.count >= TTY_FLIPBUF_SIZE)) {
- tty->flip.work.func((void *)tty);
- if (tty->flip.count >= TTY_FLIPBUF_SIZE)
- return; // if TTY_DONT_FLIP is set
+ /* no room in flip buffer, discard rx FIFO contents to clear IRQ */
+ do {
+ serial_inp(up, UART_RX);
+ up->port.icount.overrun++;
+ *status = serial_inp(up, UART_LSR);
+ } while ((*status & UART_LSR_DR) && (max_count-- > 0));
+ return; /* if TTY_DONT_FLIP is set */
}
ch = serial_inp(up, UART_RX);
*tty->flip.char_buf_ptr = ch;
next prev parent reply other threads:[~2004-10-29 21:17 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-10-29 19:55 [BUG][2.6.8.1] serial driver hangs SMP kernel, but not the UP kernel Tim_T_Murphy
2004-10-29 20:20 ` Russell King
2004-10-29 22:18 ` Paul Fulghum
2004-10-29 23:40 ` Paul Fulghum
2004-10-30 22:43 ` Alan Cox
2004-10-31 0:26 ` Paul Fulghum
2004-11-01 7:14 ` [BUG][2.6.8.1] serial driver hangs SMP kernel, but not the UPkernel Stuart MacDonald
2004-11-01 14:10 ` Paul Fulghum
2004-11-01 15:12 ` Stuart MacDonald
2004-11-01 23:02 ` Alan Cox
2004-11-02 0:18 ` Paul Fulghum
2004-10-29 21:08 ` Paul Fulghum [this message]
2004-10-29 21:04 [BUG][2.6.8.1] serial driver hangs SMP kernel, but not the UP kernel Tim_T_Murphy
2004-10-29 21:14 ` Russell King
2004-10-29 23:30 Tim_T_Murphy
2004-10-30 16:02 ` Russell King
2004-10-29 23:33 Tim_T_Murphy
2004-11-01 14:28 Tim_T_Murphy
2004-11-01 14:35 ` Russell King
2004-11-01 16:06 Tim_T_Murphy
2005-01-06 14:55 Tim_T_Murphy
2005-01-06 22:47 Tim_T_Murphy
2005-01-06 23:11 ` Alan Cox
2005-01-07 0:43 ` Paul Fulghum
2005-01-07 1:54 ` Alan Cox
2005-01-07 14:04 ` Paul Fulghum
2005-01-06 23:50 Tim_T_Murphy
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