From c13324a505c7790fe91a9df35be2e0462abccdb0 Mon Sep 17 00:00:00 2001
From: Masami Hiramatsu <mhiramat@kernel.org>
Date: Wed, 13 Feb 2019 01:12:15 +0900
Subject: x86/kprobes: Prohibit probing on functions before
 kprobe_int3_handler()

Prohibit probing on the functions called before kprobe_int3_handler()
in do_int3(). More specifically, ftrace_int3_handler(),
poke_int3_handler(), and ist_enter(). And since rcu_nmi_enter() is
called by ist_enter(), it also should be marked as NOKPROBE_SYMBOL.

Since those are handled before kprobe_int3_handler(), probing those
functions can cause a breakpoint recursion and crash the kernel.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andrea Righi <righi.andrea@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/154998793571.31052.11301258949601150994.stgit@devbox
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 kernel/rcu/tree.c | 2 ++
 1 file changed, 2 insertions(+)

(limited to 'kernel/rcu')

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 9180158756d2..74db52a0a466 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -62,6 +62,7 @@
 #include <linux/suspend.h>
 #include <linux/ftrace.h>
 #include <linux/tick.h>
+#include <linux/kprobes.h>
 
 #include "tree.h"
 #include "rcu.h"
@@ -872,6 +873,7 @@ void rcu_nmi_enter(void)
 {
 	rcu_nmi_enter_common(false);
 }
+NOKPROBE_SYMBOL(rcu_nmi_enter);
 
 /**
  * rcu_irq_enter - inform RCU that current CPU is entering irq away from idle
-- 
cgit v1.2.3