[adding back linux-usb-devel. please don't drop cc] [also adding lkml and Greg K-H]
Chris Rankin wrote: > --- Tejun Heo <[EMAIL PROTECTED]> wrote: >> Okay, here's patch against 2.6.20.11. Let's hope we're not chasing >> something which is already fixed. > > Hooray! The trick was to trace the "dev" file instead of the endpoint > directory itself. The > compressed oops is attached. Alright, it took a lot of work but the winner is the "dev" node. Gee... We could have caught this earlier unless I forgot to print the name of the last component in the initial debug patch. Well, better late than never. :-( Anyways, the problem is that the attribute "dev" is dynamically allocated using kmalloc() in device_add() and freed immediately after the file is removed in device_del(). It's basically assuming immediate-disconnect but that apparently isn't true yet. The dynamic allocation is to set the owner of the attribute to the owner of the device being registered. This is twisted in that the field is added to work around sysfs/module lifetime problem but the workaround itself is broken with regard to lifetime rules. Aieeeeeeee... This sort of things are why I implemented immediate disconnect on sysfs in the first place. So, we can fix the problem Chris is seeing by breaking module unload (by allowing it to unload too early). It doesn't sound too hot but module unloading race is much less likely than sysfs node deletion/open race. Thanks. -- tejun ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
