kernel BUG at drivers/serial/8250.c:1256!

kernel BUG at drivers/serial/8250.c:1256!

[Karol Kozimor]

Hi,

I've finally got around to test latest kernels and managed to find a bug in 
the serial subsystem, which happens during suspend.

I use a 3Com PC Card Bluetooth adapter that needs serial_cs and hci_uart
modules. Whenever I try to suspend using 2.6.10 or a newer kernel, the
following bug appears. Note that 2.6.9 works perfectly.

#v+ handwritten, 2.6.11-rc5
kernel BUG at drivers/serial/8250.c:1256!
invalid operand: 0000 [#1]
PREEMPT
[...]
EIP is at serial_unlink_irq_chain+0x4b/0x60 [8250]
[...]
Call Trace:
uart_suspend_port [serial_core]
serial_suspend [serial_cs]
serial_event [serial_cs]
send_event_callback [pcmcia]
__bus_for_each_dev
bus_for_each_dev
send_event_callback [pcmcia]
send_event [pcmcia]
send_event_callback [pcmcia]
handle_event [pcmcia]
ds_event [pcmcia]
send_event [pcmcia_core]
socket_suspend [pcmcia_core]
#v-

Photos are available here (sorry for the quality):
http://hell.org.pl/~sziwan/bug_8250-1.jpg
http://hell.org.pl/~sziwan/bug_8250-2.jpg
http://hell.org.pl/~sziwan/bug_8250-3.jpg

I'll be happy to provide whatever information is needed.

Best regards,

-- 
Karol 'sziwan' Kozimor
sziwan@hell.org.pl

Re: kernel BUG at drivers/serial/8250.c:1256!

[Russell King]

On Wed, Mar 02, 2005 at 12:09:46AM +0100, Karol Kozimor wrote:
> I've finally got around to test latest kernels and managed to find a bug in 
> the serial subsystem, which happens during suspend.

Yes, serial_cs is claiming that we don't have a device associated with
the port, so we're treating it as a legacy port.  However, serial_cs is
implementing the suspend/resume methods.  This is wrong, since that
means the port will be suspended twice, and hence causes this bug.

serial_cs needs to register the ports along with the PCMCIA device with
which the port belongs to.  This will stop it being treated as a legacy
serial port.

Unfortunately, it's too late tonight for me to dig into PCMCIA to work
out how we get at the device structure - I can't find any examples off
hand either.  Therefore, it may be a while before I can produce a patch
to resolve this.

-- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of:  2.6 Serial core

Re: kernel BUG at drivers/serial/8250.c:1256!

[Dominik Brodowski]

On Tue, Mar 01, 2005 at 11:37:20PM +0000, Russell King wrote:
> On Wed, Mar 02, 2005 at 12:09:46AM +0100, Karol Kozimor wrote:
> > I've finally got around to test latest kernels and managed to find a bug in 
> > the serial subsystem, which happens during suspend.
> 
> Yes, serial_cs is claiming that we don't have a device associated with
> the port, so we're treating it as a legacy port.  However, serial_cs is
> implementing the suspend/resume methods.  This is wrong, since that
> means the port will be suspended twice, and hence causes this bug.
> 
> serial_cs needs to register the ports along with the PCMCIA device with
> which the port belongs to.  This will stop it being treated as a legacy
> serial port.
> 
> Unfortunately, it's too late tonight for me to dig into PCMCIA to work
> out how we get at the device structure - I can't find any examples off
> hand either.

For the time being:

{
	client_handle_t handle = ...
	struct device *dev;

	dev = &handle_to_dev(handle);
}


	Dominik

Re: kernel BUG at drivers/serial/8250.c:1256!

[Russell King]

On Tue, Mar 01, 2005 at 11:37:20PM +0000, Russell King wrote:
> On Wed, Mar 02, 2005 at 12:09:46AM +0100, Karol Kozimor wrote:
> > I've finally got around to test latest kernels and managed to find a bug in 
> > the serial subsystem, which happens during suspend.
> 
> Yes, serial_cs is claiming that we don't have a device associated with
> the port, so we're treating it as a legacy port.  However, serial_cs is
> implementing the suspend/resume methods.  This is wrong, since that
> means the port will be suspended twice, and hence causes this bug.

Ok, here's the patch.  Please test and let me know if it resolves your
problem.  Thanks.

diff -up -x BitKeeper -x ChangeSet -x SCCS -x _xlk -x *.orig -x *.rej orig/drivers/serial/serial_cs.c linux/drivers/serial/serial_cs.c
--- orig/drivers/serial/serial_cs.c	Sun Feb  6 11:38:41 2005
+++ linux/drivers/serial/serial_cs.c	Sat Mar  5 14:09:53 2005
@@ -289,7 +289,8 @@ static void serial_detach(dev_link_t * l
 
 /*====================================================================*/
 
-static int setup_serial(struct serial_info * info, kio_addr_t iobase, int irq)
+static int setup_serial(client_handle_t handle, struct serial_info * info,
+			kio_addr_t iobase, int irq)
 {
 	struct uart_port port;
 	int line;
@@ -299,6 +300,7 @@ static int setup_serial(struct serial_in
 	port.irq = irq;
 	port.flags = UPF_BOOT_AUTOCONF | UPF_SKIP_TEST | UPF_SHARE_IRQ;
 	port.uartclk = 1843200;
+	port.dev = &handle_to_dev(handle);
 	if (buggy_uart)
 		port.flags |= UPF_BUGGY_UART;
 	line = serial8250_register_port(&port);
@@ -376,7 +378,7 @@ static int simple_config(dev_link_t *lin
 			info->slave = 1;
 		}
 		if (info->slave)
-			return setup_serial(info, port, config.AssignedIRQ);
+			return setup_serial(handle, info, port, config.AssignedIRQ);
 	}
 	link->conf.Vcc = config.Vcc;
 
@@ -451,7 +453,7 @@ next_entry:
 		return -1;
 	}
 
-	return setup_serial(info, link->io.BasePort1, link->irq.AssignedIRQ);
+	return setup_serial(handle, info, link->io.BasePort1, link->irq.AssignedIRQ);
 }
 
 static int multi_config(dev_link_t * link)
@@ -546,21 +548,21 @@ static int multi_config(dev_link_t * lin
 	   8 registers are for the UART, the others are extra registers */
 	if (info->manfid == MANFID_OXSEMI) {
 		if (cf->index == 1 || cf->index == 3) {
-			setup_serial(info, base2, link->irq.AssignedIRQ);
+			setup_serial(handle, info, base2, link->irq.AssignedIRQ);
 			outb(12, link->io.BasePort1 + 1);
 		} else {
-			setup_serial(info, link->io.BasePort1, link->irq.AssignedIRQ);
+			setup_serial(handle, info, link->io.BasePort1, link->irq.AssignedIRQ);
 			outb(12, base2 + 1);
 		}
 		return 0;
 	}
 
-	setup_serial(info, link->io.BasePort1, link->irq.AssignedIRQ);
+	setup_serial(handle, info, link->io.BasePort1, link->irq.AssignedIRQ);
 	/* The Nokia cards are not really multiport cards */
 	if (info->manfid == MANFID_NOKIA)
 		return 0;
 	for (i = 0; i < info->multi - 1; i++)
-		setup_serial(info, base2 + (8 * i), link->irq.AssignedIRQ);
+		setup_serial(handle, info, base2 + (8 * i), link->irq.AssignedIRQ);
 
 	return 0;
 }


-- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of:  2.6 Serial core

Re: kernel BUG at drivers/serial/8250.c:1256!

[Karol Kozimor]

Thus wrote Russell King:
> Ok, here's the patch.  Please test and let me know if it resolves your
> problem.  Thanks.

Oh, I thought I did reply to your previous mail. In case you didn't get it,
yes, the patch fixes the problem.
Thanks,

-- 
Karol 'sziwan' Kozimor
sziwan@hell.org.pl