[PATCH] kprobes: fix race in aggregate kprobe registration

[PATCH] kprobes: fix race in aggregate kprobe registration

When registering multiple kprobes at the same address, we leave a small
window where the kprobe hlist will not contain a reference to the
registered kprobe, leading to potentially, a system crash if the breakpoint
is hit on another processor.

Patch below now automically relpace the old kprobe with the new
kprobe from the hash list.

Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>