Re: [BUG]: problem when shutting down ppp connection since 2.5.70
From: Paul Rolland <hidden>
Date: 2003-07-14 09:16:04
Hello, I've applied the patch from Stephen on top of the 2.6.0-test1 kernel, and here is the result : Jul 14 10:57:01 donald kernel: dst route cache has 0 references Jul 14 10:57:01 donald kernel: unregister_netdevice: waiting for tap0 to become free. Usage count = -3 Jul 14 10:57:10 donald kernel: dst route cache has 0 references Jul 14 10:57:10 donald kernel: unregister_netdevice: waiting for tap0 to become free. Usage count = -3 Jul 14 10:57:20 donald kernel: dst route cache has 0 references Jul 14 10:57:20 donald kernel: unregister_netdevice: waiting for tap0 to become free. Usage count = -3 Jul 14 10:57:31 donald kernel: dst route cache has 0 references Jul 14 10:57:31 donald kernel: unregister_netdevice: waiting for tap0 to become free. Usage count = -3 This is a big change compared to 2.5.74 (.75 not tested). I guess a negative usage count should be considered as valid by unregister_netdevice. What about :
--- dev.c 2003-07-14 11:13:23.000000000 +0200
+++ dev.c.orig 2003-07-14 11:13:01.000000000 +0200@@ -2746,7 +2746,7 @@ unsigned long rebroadcast_time, warning_time; rebroadcast_time = warning_time = jiffies; - while (atomic_read(&dev->refcnt) > 0) { + while (atomic_read(&dev->refcnt) != 0) { if (time_after(jiffies, rebroadcast_time + 1 * HZ)) { rtnl_shlock(); rtnl_exlock();
Regards, Paul ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ REHAB is for quitters. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Paul Rolland, rol@witbe.net Witbe.net SA Directeur Associe -- Please no HTML, I'm not a browser - Pas d'HTML, je ne suis pas un navigateur "Some people dream of success... while others wake up and work hard at it"
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-----Original Message----- From: Stephen Hemminger [mailto:shemminger@osdl.org] Sent: Wednesday, July 09, 2003 8:44 PM To: Paul Rolland; cfriesen@nortelnetworks.com; paulus@samba.org Cc: linux-ppp@vger.kernel.org; netdev@oss.sgi.com Subject: Re: [BUG]: problem when shutting down ppp connection since 2.5.70 The problem is that some protocol is still holding a reference to the device. This is a bug in the protocol, and needs to be fixed (ie not a ppp bug). Try building a kernel with only IPv4, eliminate all others then add back until you find the culprit. The following patch may help also. diff -Nru a/net/core/dev.c b/net/core/dev.c--- a/net/core/dev.c Wed Jul 9 11:40:56 2003 +++ b/net/core/dev.c Wed Jul 9 11:40:56 2003@@ -72,6 +72,8 @@ * - netif_rx() feedback */ +#define DEBUG 1 + #include <asm/uaccess.h> #include <asm/system.h> #include <asm/bitops.h>@@ -2704,6 +2706,8 @@ goto out; } +extern void dst_dumpref(const struct net_device *dev); + static void netdev_wait_allrefs(struct net_device *dev) { unsigned long rebroadcast_time, warning_time;@@ -2740,6 +2744,30 @@ current->state = TASK_RUNNING; if (time_after(jiffies, warning_time + 10 * HZ)) { +#ifdef DEBUG + dst_dumpref(dev); + + if (dev->atalk_ptr) + printk(KERN_INFO"unregister_netdevice: " + " %s: probably in use as AppleTalk device\n", dev->name); + if (dev->ip_ptr) + printk(KERN_INFO "unregister_netdevice: " + " %s: probably in use as IPv4 device\n", dev->name); + + if (dev->atalk_ptr) + printk(KERN_INFO "unregister_netdevice: " + " %s: probably in use as DECnet device\n", dev->name); + if (dev->ip6_ptr) + printk(KERN_INFO "unregister_netdevice: " + " %s: probably in use as IPv6 device\n", dev->name); + + if (dev->ec_ptr) + printk(KERN_INFO "unregister_netdevice: " + " %s: probably in use as Econet device\n", dev->name); + if (dev->ax25_ptr) + printk(KERN_INFO "unregister_netdevice: " + " %s: probably in use as AX.25 device\n", dev->name); #endif printk(KERN_EMERG "unregister_netdevice: " "waiting for %s to become free. Usage " "count = %d\n", diff -Nru a/net/core/dst.c b/net/core/dst.c--- a/net/core/dst.c Wed Jul 9 11:40:56 2003 +++ b/net/core/dst.c Wed Jul 9 11:40:56 2003@@ -41,6 +41,21 @@ static struct timer_list dst_gc_timer = TIMER_INITIALIZER(dst_run_gc, 0, DST_GC_MIN); + +void dst_dumpref(const struct net_device *dev) +{ + struct dst_entry *dst; + int count = 0; + + spin_lock_bh(&dst_lock); + for (dst = dst_garbage_list; dst; dst = dst->next) { + if (dst->dev == dev) ++count; + } + spin_unlock_bh(&dst_lock); + + printk(KERN_INFO "dst route cache has %d references\n",count); } + static void dst_run_gc(unsigned long dummy) { int delayed = 0;