On Tue, Nov 06, 2018 at 04:34:08PM +0000, Lorenzo Pieralisi wrote:
> The question is whether we really need to dynamically patch the kernel
> with ftrace to achieve what that patch does.
>
> Furthermore, it would also be good to report what bugs we are actually
> fixing, from what you are writing falling back to the current method if
> !DYNAMIC_FTRACE_WITH_REGS is broken in many ways and I would start with
> fixing the current behaviour with something that does not depend on arch
> features that may not even be implemented.
There are two problems with the current method:
1. It may dereference pci_dev after it was freed
2. The pci_dev's children inherit its fake pci_bus's ops on
enumeration
Both result in kernel panic.
The dynamic kernel patch just seemed like a cool way to inject errors
without messing with the driver's structures. But if there's a more
elegant way to do it, I'm all for it.
