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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Andrea Righi <righi.andrea@gmail.com>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Arnaldo Carvalho de Melo <acme@redhat.com>,
        Jiri Olsa <jolsa@redhat.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Steven Rostedt <rostedt@goodmis.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@kernel.org>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.4 043/168] kprobes: Prohibit probing on bsearch()
Date:   Wed, 24 Apr 2019 19:08:07 +0200
Message-Id: <20190424170926.351880840@linuxfoundation.org>
In-Reply-To: <20190424170923.452349382@linuxfoundation.org>
References: <20190424170923.452349382@linuxfoundation.org>
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[ Upstream commit 02106f883cd745523f7766d90a739f983f19e650 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 lib/bsearch.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/lib/bsearch.c b/lib/bsearch.c
index e33c179089db..d50048446b77 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
@@ -51,3 +52,4 @@ void *bsearch(const void *key, const void *base, size_t num, size_t size,
 	return NULL;
 }
 EXPORT_SYMBOL(bsearch);
+NOKPROBE_SYMBOL(bsearch);
-- 
2.19.1