From 02106f883cd745523f7766d90a739f983f19e650 Mon Sep 17 00:00:00 2001
From: Andrea Righi <righi.andrea@gmail.com>
Date: Wed, 13 Feb 2019 01:15:34 +0900
Subject: [PATCH] kprobes: Prohibit probing on bsearch()

Since kprobe breakpoing handler is using bsearch(), probing on this
routine can cause recursive breakpoint problem.

int3
 ->do_int3()
   ->ftrace_int3_handler()
     ->ftrace_location()
       ->ftrace_location_range()
         ->bsearch() -> int3

Prohibit probing on bsearch().

Signed-off-by: Andrea Righi <righi.andrea@gmail.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.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/154998813406.31052.8791425358974650922.stgit@devbox
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 lib/bsearch.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/lib/bsearch.c b/lib/bsearch.c
index 18b445b010c3..82512fe7b33c 100644
--- a/lib/bsearch.c
+++ b/lib/bsearch.c
@@ -11,6 +11,7 @@
 
 #include <linux/export.h>
 #include <linux/bsearch.h>
+#include <linux/kprobes.h>
 
 /*
  * bsearch - binary search an array of elements
@@ -53,3 +54,4 @@ void *bsearch(const void *key, const void *base, size_t num, size_t size,
 	return NULL;
 }
 EXPORT_SYMBOL(bsearch);
+NOKPROBE_SYMBOL(bsearch);
-- 
2.30.2