kprobes/x86: Fix removed int3 checking order

Fix kprobe/x86 to check removed int3 when failing to get kprobe
from hlist. Since we have a time window between checking int3
exists on probed address and getting kprobe on that address,
we can have following scenario:

 -------
 CPU1                     CPU2
 hit int3
 check int3 exists
                          remove int3
                          remove kprobe from hlist
 get kprobe from hlist
 no kprobe->OOPS!
 -------

This patch moves int3 checking if there is no kprobe on that
address for fixing this problem as follows:

 ------
 CPU1                     CPU2
 hit int3
                          remove int3
                          remove kprobe from hlist
 get kprobe from hlist
 no kprobe->check int3 exists
          ->rollback&retry
 ------

Signed-off-by: Masami Hiramatsu <[email protected]>
Acked-by: Ananth N Mavinakayanahalli <[email protected]>
Cc: systemtap <[email protected]>
Cc: DLE <[email protected]>
Cc: Dave Anderson <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
LKML-Reference: <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>

0 files changed, 0 insertions, 0 deletions