kprobes/x86-64: Allow to reenter probe on post_handler

Allow to reenter probe on the post_handler of another probe on x86-64,
because x86-64 already allows reentering int3.
In that case, reentered probe just increases kp.nmissed and returns.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
LKML-Reference: <20090827172304.8246.4822.stgit@localhost.localdomain>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

diff --git a/arch/x86/kernel/kprobes.c b/arch/x86/kernel/kprobes.c
index e0fb615..c5f1f11 100644 (file)
--- a/arch/x86/kernel/kprobes.c
+++ b/arch/x86/kernel/kprobes.c
@@ -463,17 +463,6 @@ static int __kprobes reenter_kprobe(struct kprobe *p, struct pt_regs *regs,
 {
        switch (kcb->kprobe_status) {
        case KPROBE_HIT_SSDONE:
-#ifdef CONFIG_X86_64
-               /* TODO: Provide re-entrancy from post_kprobes_handler() and
-                * avoid exception stack corruption while single-stepping on
-                * the instruction of the new probe.
-                */
-               arch_disarm_kprobe(p);
-               regs->ip = (unsigned long)p->addr;
-               reset_current_kprobe();
-               preempt_enable_no_resched();
-               break;
-#endif
        case KPROBE_HIT_ACTIVE:
                save_previous_kprobe(kcb);
                set_current_kprobe(p, regs, kcb);