[PATCH -tip v3 08/10] kprobes: Prohibit probing on RCU debug routine

Masami Hiramatsu
2019-02-12T16:15:04Z

Since kprobe itself depends on RCU, probing on RCU debug
routine can cause recursive breakpoint problem.
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>
---
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?