Re: modular net drivers

[Keith Owens <kaos@xxxxxxxxxx>]

On Mon, 19 Jun 2000 23:54:30 +1000, 
Andrew Morton <andrewm@xxxxxxxxxx> wrote:
>--- linux-2.4.0-test1-ac21/net/core/dev.c      Mon Jun 19 16:47:54 2000
>+++ linux-akpm/net/core/dev.c  Mon Jun 19 21:28:14 2000
>@@ -664,8 +665,13 @@
>        *      Call device private open method
>        */
>        
>-      if (dev->open) 
>+      if (dev->open) {
>+              if (dev->owner)
>+                      __MOD_INC_USE_COUNT(dev->owner);
>               ret = dev->open(dev);
>+              if (ret != 0 && dev->owner)
>+                      __MOD_DEC_USE_COUNT(dev->owner);
>+      }

Racy.  The module referred to by dev->owner might be in the middle of
being unloaded.  You need try_inc_mod_count() with a check on its
result instead of __MOD_INC_USE_COUNT.