提交 18fec7d8 编写于 作者: F Frederic Weisbecker 提交者: Paul E. McKenney

rcu: Improve synchronize_rcu() diagnostics

Although TREE_PREEMPT_RCU indirectly uses might_sleep() to detect illegal
use of synchronize_sched() and synchronize_rcu_bh() from within an RCU
read-side critical section, this might_sleep() check is bypassed when
there is only a single CPU (for example, when running an SMP kernel on
a single-CPU system).  This patch therefore adds a might_sleep() call
to the rcu_blocking_is_gp() check that is unconditionally invoked from
both synchronize_sched() and synchronize_rcu_bh().
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
上级 4c62abc9
......@@ -83,6 +83,7 @@ extern void rcu_sched_force_quiescent_state(void);
/* A context switch is a grace period for RCU-sched and RCU-bh. */
static inline int rcu_blocking_is_gp(void)
{
might_sleep(); /* Check for RCU read-side critical section. */
return num_online_cpus() == 1;
}
......
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