Subject: Re: [Bugme-new] [Bug 10327] New: keyboard stops responding after "ifdown eth0"

From: Andrew Morton <[email-masked]>
Date: Wed, 26 Mar 2008 10:29:31 -0700

On Wed, 26 Mar 2008 10:19:40 +0100
Marcus Better <[email-masked]> wrote:

> Andrew Morton wrote:
> > 	( sleep 10 ; echo t > /proc/sysrq-trigger ) &
> > 	ifdown eth0
> > 
> > 
> > - See if the sysrq-t output made it to /var/log/messages
> 
> No, not a word. It hung after printing this:
> 
> ...
> DHCPRELEASE ...
> send_packet: Network is unreachable
> send_packet: please consult README ...
> sky2 eth0: disabling interface
> ~# sky2 eth0: enabling interface
> 
> I'm running ifplugd, but this time there was no network cable connected. 
> Also ran from virtual console this time, the keyboard locked up like before.
> 
> SysRq keys work, so I could do sysrq-s, sysrq-b. Also pressed sysrq-t 
> before rebooting.

It certainy does sound like networking has gummed up the keventd queue(s).

> Any use trying netconsole? Can I run it over the wireless interface?

I don't think many (or any?) wireless drivers support netconsole.

I'd suggest running (and perhaps suitably modifying) this:

diff -puN drivers/net/sky2.c~a drivers/net/sky2.c
--- a/drivers/net/sky2.c~a
+++ a/drivers/net/sky2.c
@@ -50,6 +50,8 @@
 
 #include "sky2.h"
 
+#define D() printk("%s:%d\n", __FILE__, __LINE__)
+
 #define DRV_NAME		"sky2"
 #define DRV_VERSION		"1.21"
 #define PFX			DRV_NAME " "
@@ -2931,32 +2933,42 @@ static void sky2_restart(struct work_str
 	struct net_device *dev;
 	int i, err;
 
+	D();
 	rtnl_lock();
+	D();
 	for (i = 0; i < hw->ports; i++) {
+		D();
 		dev = hw->dev[i];
 		if (netif_running(dev))
 			sky2_down(dev);
 	}
-
+	D();
 	napi_disable(&hw->napi);
+	D();
 	sky2_write32(hw, B0_IMSK, 0);
 	sky2_reset(hw);
 	sky2_write32(hw, B0_IMSK, Y2_IS_BASE);
 	napi_enable(&hw->napi);
-
+	D();
 	for (i = 0; i < hw->ports; i++) {
+		D();
 		dev = hw->dev[i];
 		if (netif_running(dev)) {
+			D();
 			err = sky2_up(dev);
+			D();
 			if (err) {
+				D();
 				printk(KERN_INFO PFX "%s: could not restart %d\n",
 				       dev->name, err);
 				dev_close(dev);
+			D();
 			}
 		}
 	}
-
+	D();
 	rtnl_unlock();
+	D();
 }
 
 static inline u8 sky2_wol_supported(const struct sky2_hw *hw)
_

to see if things are getting stuck and if so, where.