On Thu, Mar 06, 2008 at 09:58:41AM -0800, Joe Buck wrote:
If the kernel allows state to leak from one process to another,
for example from a process running as root to a process running as an
ordinary user, it's a bug, with possible security implications.
I don't think that it is relevant in your case. If you have the
signal handler in something that does not share the VM with the
interrupted thread, you will have a context switch which is supposed
to store the direction flag and restore the one from the handling
thread. If you share the VM there is no context switch but you have
access to the exact same memory with the exact same rights, making the
leak irrelevant.