[PATCH 8/9] kprobes: Prohibit probing on RCU debug routine

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?