Detect RCU read-side overflows

[urcu.git] / urcu / static / urcu.h

diff --git a/urcu/static/urcu.h b/urcu/static/urcu.h
index af8eee442d3849f5756423d7337d16c93f712f34..3fb457b4e3e00916b2a2e06e172b4eced08f0df0 100644 (file)
--- a/urcu/static/urcu.h
+++ b/urcu/static/urcu.h
@@ -42,6 +42,7 @@
 #include <urcu/futex.h>
 #include <urcu/tls-compat.h>
 #include <urcu/rand-compat.h>
+#include <urcu/debug.h>
 
 #ifdef __cplusplus
 extern "C" {
@@ -79,12 +80,6 @@ enum rcu_state {
        RCU_READER_INACTIVE,
 };
 
-#ifdef DEBUG_RCU
-#define rcu_assert(args...)    assert(args)
-#else
-#define rcu_assert(args...)
-#endif
-
 /*
  * RCU memory barrier broadcast group. Currently, only broadcast to all process
  * threads is supported (group 0).
@@ -157,6 +152,8 @@ struct rcu_reader {
        /* Data used for registry */
        struct cds_list_head node __attribute__((aligned(CAA_CACHE_LINE_SIZE)));
        pthread_t tid;
+       /* Reader registered flag, for internal checks. */
+       unsigned int registered:1;
 };
 
 extern DECLARE_URCU_TLS(struct rcu_reader, rcu_reader);
@@ -224,8 +221,10 @@ static inline void _rcu_read_lock(void)
 {
        unsigned long tmp;
 
+       urcu_assert(URCU_TLS(rcu_reader).registered);
        cmm_barrier();
        tmp = URCU_TLS(rcu_reader).ctr;
+       urcu_assert((tmp & RCU_GP_CTR_NEST_MASK) != RCU_GP_CTR_NEST_MASK);
        _rcu_read_lock_update(tmp);
 }
 
@@ -241,11 +240,11 @@ static inline void _rcu_read_unlock_update_and_wakeup(unsigned long tmp)
 {
        if (caa_likely((tmp & RCU_GP_CTR_NEST_MASK) == RCU_GP_COUNT)) {
                smp_mb_slave(RCU_MB_GROUP);
-               _CMM_STORE_SHARED(URCU_TLS(rcu_reader).ctr, URCU_TLS(rcu_reader).ctr - RCU_GP_COUNT);
+               _CMM_STORE_SHARED(URCU_TLS(rcu_reader).ctr, tmp - RCU_GP_COUNT);
                smp_mb_slave(RCU_MB_GROUP);
                wake_up_gp();
        } else
-               _CMM_STORE_SHARED(URCU_TLS(rcu_reader).ctr, URCU_TLS(rcu_reader).ctr - RCU_GP_COUNT);
+               _CMM_STORE_SHARED(URCU_TLS(rcu_reader).ctr, tmp - RCU_GP_COUNT);
 }
 
 /*
@@ -257,7 +256,9 @@ static inline void _rcu_read_unlock(void)
 {
        unsigned long tmp;
 
+       urcu_assert(URCU_TLS(rcu_reader).registered);
        tmp = URCU_TLS(rcu_reader).ctr;
+       urcu_assert(tmp & RCU_GP_CTR_NEST_MASK);
        _rcu_read_unlock_update_and_wakeup(tmp);
        cmm_barrier();  /* Ensure the compiler does not reorder us with mutex */
 }