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rcu: Add preemptibility checks in rcu_sched_qs() and rcu_bh_qs()

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This commit adds WARN_ON_ONCE() calls that trigger if either
rcu_sched_qs() or rcu_bh_qs() are invoked with preemption enabled.
In the immortal words of Peter Zijlstra: "these are much harder to ignore
than comments".

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit is contained in:
Paul E. McKenney 2017-04-27 16:13:53 -07:00
parent c75e9caaf8
commit f4687d2637
1 changed files with 2 additions and 0 deletions
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2
kernel/rcu/tree.c
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@ -250,6 +250,7 @@ static int rcu_gp_in_progress(struct rcu_state *rsp)
*/ */
void rcu_sched_qs(void) void rcu_sched_qs(void)
{ {
RCU_LOCKDEP_WARN(preemptible(), "rcu_sched_qs() invoked with preemption enabled!!!");
if (!__this_cpu_read(rcu_sched_data.cpu_no_qs.s)) if (!__this_cpu_read(rcu_sched_data.cpu_no_qs.s))
return; return;
trace_rcu_grace_period(TPS("rcu_sched"), trace_rcu_grace_period(TPS("rcu_sched"),
@ -265,6 +266,7 @@ void rcu_sched_qs(void)
void rcu_bh_qs(void) void rcu_bh_qs(void)
{ {
RCU_LOCKDEP_WARN(preemptible(), "rcu_bh_qs() invoked with preemption enabled!!!");
if (__this_cpu_read(rcu_bh_data.cpu_no_qs.s)) { if (__this_cpu_read(rcu_bh_data.cpu_no_qs.s)) {
trace_rcu_grace_period(TPS("rcu_bh"), trace_rcu_grace_period(TPS("rcu_bh"),
__this_cpu_read(rcu_bh_data.gpnum), __this_cpu_read(rcu_bh_data.gpnum),