[tip:perf/core] kprobes: Prohibit probing on RCU debug routine

tip-bot for Masami Hiramatsu
2019-02-13T09:03:56Z

Commit-ID: a39f15b9644fac3f950f522c39e667c3af25c588
Gitweb: https://git.kernel.org/tip/a39f15b9644fac3f950f522c39e667c3af25c588
Author: Masami Hiramatsu <mhiramat@kernel.org>
AuthorDate: Wed, 13 Feb 2019 01:14:37 +0900
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Wed, 13 Feb 2019 08:16:40 +0100

kprobes: Prohibit probing on RCU debug routine

Since kprobe itself depends on RCU, probing on RCU debug
routine can cause recursive breakpoint bugs.

Prohibit probing on RCU debug routines.

int3
->do_int3()
->ist_enter()
->RCU_LOCKDEP_WARN()
->debug_lockdep_rcu_enabled() -> int3

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/154998807741.31052.11229157537816341591.stgit@devbox
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
kernel/rcu/update.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c
index 1971869c4072..f4ca36d92138 100644
--- a/kernel/rcu/update.c
+++ b/kernel/rcu/update.c
@@ -52,6 +52,7 @@
#include <linux/tick.h>
#include <linux/rcupdate_wait.h>
#include <linux/sched/isolation.h>
+#include <linux/kprobes.h>

#define CREATE_TRACE_POINTS

@@ -249,6 +250,7 @@ int notrace debug_lockdep_rcu_enabled(void)
current->lockdep_recursion == 0;
}
EXPORT_SYMBOL_GPL(debug_lockdep_rcu_enabled);
+NOKPROBE_SYMBOL(debug_lockdep_rcu_enabled);

/**
* rcu_read_lock_held() - might we be in RCU read-side critical section?