[PATCH -tip] kprobes/x86: Use preempt_enable() in optimized_callback()

[Masami Hiramatsu]

Since commit a19b2e3d7839 ("kprobes/x86: Remove IRQ disabling from
ftrace-based/optimized kprobesâ) removes local_irq_save/restore()
from optimized_callback(), the handler does not protected against
reschedule interrupt. If it is able to be preempted (rescheduled)
by such interrupt, we don't need to use _no_resched macro.
Let's use preempt_enable() instead.

Fixes: a19b2e3d7839 ("kprobes/x86: Remove IRQ disabling from ftrace-based/optimized kprobesâ)
Link: https://lkml.kernel.org/r/37CB98C2-AF9B-475B-8B2D-7B414DC491F3@xxxxxxxxxx
Reported-by: Nadav Amit <namit@xxxxxxxxxx>
Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
---
 arch/x86/kernel/kprobes/opt.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/kprobes/opt.c b/arch/x86/kernel/kprobes/opt.c
index eaf02f2e7300..40b16b270656 100644
--- a/arch/x86/kernel/kprobes/opt.c
+++ b/arch/x86/kernel/kprobes/opt.c
@@ -179,7 +179,7 @@ optimized_callback(struct optimized_kprobe *op, struct pt_regs *regs)
 		opt_pre_handler(&op->kp, regs);
 		__this_cpu_write(current_kprobe, NULL);
 	}
-	preempt_enable_no_resched();
+	preempt_enable();
 }
 NOKPROBE_SYMBOL(optimized_callback);