Hello, On Fri, Aug 16, 2013 at 06:38:58PM +0200, Richard Weinberger wrote: > > cc'ing uml people. Hey, guys, workqueue uses proble_kernel_read() to > > print out workqueue related information during oops because those > > events are completely asynchronous and workqueue states may not be > > consistently accessible. It seems like uml doesn't implement > > probe_kernel_read() and tries direct derference of incorrect pointers > > leading to its own oops. Maybe uml should check whether the memory is > > mapped from probe_kernel_read()? > > You are already talking to UML people. ;)
Ooh... :) > Anyway, I'll investigate into that. > What I see so far is that pwq is NULL after probe_kernel_read(). Yeah, and that should be fine. &pwq->wq would be just an offset of wq from NULL which is an invalid pointer but probe_kernel_read() should be able to handle that and probably just return 0 or -1 (all bits set). I *think* what's necessary is making probe_kernel_read() use mincore() to fine out whether the requested address is mapped (it should return -EFAULT if not) and try to dereference the address iff it's mapped. Thanks. -- tejun -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
