Hi lkml-members, I recently had a problem with appletalk. After starting atalkd on a TAP interface and stopping it later, unregister_netdevice() just stated | unregister_netdevice: waiting for tap0 to become free. Usage count = -1 So I assume there is a problem in the appletalk code, but I didn't try reproducing that on other systems so far. I changed my kernel to "correct" a negative refcnt to 0 and that kind of fixes the problem. I'm not sure whether this could break anything, but certainly waiting for a device to become free is no use when there is a negative number of users, so I think it would be better to allow the system to shut down cleanly in this case. Here's m suggestion: #v+ --- linux-2.6.11-orig/net/core/dev.c 2005-03-02 08:38:09.000000000 +0100 +++ linux-2.6.11/net/core/dev.c 2005-04-09 16:44:42.000000000 +0200 @@ -2876,7 +2876,7 @@ 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(); @@ -2910,6 +2910,13 @@ warning_time = jiffies; } } + if (atomic_read(&dev->refcnt) != 0) { + printk(KERN_ERR "unregister_netdevice: " + "%s has negative refcnt (%d). " + "This should never happen! Setting refcnt to 0.\n", + dev->name, atomic_read(&dev->refcnt)); + atomic_set(&dev->refcnt, 0); + } } /* The sequence is: #v- Greets, Felix PS: Please note I'm not subscribed to lkml and CC me in replies, thanks. -- | /"\ ASCII Ribbon | Felix M. Palmen (Zirias) http://zirias.ath.cx/ | | \ / Campaign Against | [email protected] encrypted mail welcome | | X HTML In Mail | PGP key: http://zirias.ath.cx/pub.txt | | / \ And News | ED9B 62D0 BE39 32F9 2488 5D0C 8177 9D80 5ECF F683 |
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