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rcu: Add lockdep_assert_held() teeth to tree_plugin.h

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Comments can be helpful, but assertions carry more force.  This commit
therefore adds lockdep_assert_held() and RCU_LOCKDEP_WARN() calls to
enforce lock-held and interrupt-disabled preconditions.

Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit is contained in:
Paul E. McKenney 2017-04-28 13:19:28 -07:00
parent c0b334c5bf
commit ea9b0c8a26
1 changed files with 17 additions and 0 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

17
kernel/rcu/tree_plugin.h
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@ -181,6 +181,8 @@ static void rcu_preempt_ctxt_queue(struct rcu_node *rnp, struct rcu_data *rdp)
(rnp->expmask & rdp->grpmask ? RCU_EXP_BLKD : 0);
struct task_struct *t = current;
lockdep_assert_held(&rnp->lock);
/*
* Decide where to queue the newly blocked task. In theory,
* this could be an if-statement. In practice, when I tried
@ -289,6 +291,7 @@ static void rcu_preempt_ctxt_queue(struct rcu_node *rnp, struct rcu_data *rdp)
*/
static void rcu_preempt_qs(void)
{
RCU_LOCKDEP_WARN(preemptible(), "rcu_preempt_qs() invoked with preemption enabled!!!\n");
if (__this_cpu_read(rcu_data_p->cpu_no_qs.s)) {
trace_rcu_grace_period(TPS("rcu_preempt"),
__this_cpu_read(rcu_data_p->gpnum),
@ -318,6 +321,7 @@ static void rcu_preempt_note_context_switch(bool preempt)
struct rcu_data *rdp;
struct rcu_node *rnp;
RCU_LOCKDEP_WARN(!irqs_disabled(), "rcu_preempt_note_context_switch() invoked with interrupts enabled!!!\n");
WARN_ON_ONCE(!preempt && t->rcu_read_lock_nesting > 0);
if (t->rcu_read_lock_nesting > 0 &&
!t->rcu_read_unlock_special.b.blocked) {
@ -634,6 +638,7 @@ static int rcu_print_task_exp_stall(struct rcu_node *rnp)
*/
static void rcu_preempt_check_blocked_tasks(struct rcu_node *rnp)
{
RCU_LOCKDEP_WARN(preemptible(), "rcu_preempt_check_blocked_tasks() invoked with preemption enabled!!!\n");
WARN_ON_ONCE(rcu_preempt_blocked_readers_cgp(rnp));
if (rcu_preempt_has_tasks(rnp))
rnp->gp_tasks = rnp->blkd_tasks.next;
@ -1024,6 +1029,7 @@ static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags)
{
struct task_struct *t;
lockdep_assert_held(&rnp->lock);
if (!rcu_preempt_blocked_readers_cgp(rnp) && rnp->exp_tasks == NULL) {
rnp->n_balk_exp_gp_tasks++;
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
@ -1404,6 +1410,7 @@ int rcu_needs_cpu(u64 basemono, u64 *nextevt)
struct rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks);
unsigned long dj;
RCU_LOCKDEP_WARN(!irqs_disabled(), "rcu_needs_cpu() invoked with irqs enabled!!!");
if (IS_ENABLED(CONFIG_RCU_NOCB_CPU_ALL)) {
*nextevt = KTIME_MAX;
return 0;
@ -1456,6 +1463,7 @@ static void rcu_prepare_for_idle(void)
struct rcu_state *rsp;
int tne;
RCU_LOCKDEP_WARN(!irqs_disabled(), "rcu_prepare_for_idle() invoked with irqs enabled!!!");
if (IS_ENABLED(CONFIG_RCU_NOCB_CPU_ALL) ||
rcu_is_nocb_cpu(smp_processor_id()))
return;
@ -1511,6 +1519,7 @@ static void rcu_prepare_for_idle(void)
*/
static void rcu_cleanup_after_idle(void)
{
RCU_LOCKDEP_WARN(!irqs_disabled(), "rcu_cleanup_after_idle() invoked with irqs enabled!!!");
if (IS_ENABLED(CONFIG_RCU_NOCB_CPU_ALL) ||
rcu_is_nocb_cpu(smp_processor_id()))
return;
@ -2544,6 +2553,8 @@ static void rcu_sysidle_enter(int irq)
unsigned long j;
struct rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks);
RCU_LOCKDEP_WARN(!irqs_disabled(), "rcu_sysidle_enter() invoked with irqs enabled!!!");
/* If there are no nohz_full= CPUs, no need to track this. */
if (!tick_nohz_full_enabled())
return;
@ -2615,6 +2626,8 @@ static void rcu_sysidle_exit(int irq)
{
struct rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks);
RCU_LOCKDEP_WARN(!irqs_disabled(), "rcu_sysidle_exit() invoked with irqs enabled!!!");
/* If there are no nohz_full= CPUs, no need to track this. */
if (!tick_nohz_full_enabled())
return;
@ -2674,6 +2687,8 @@ static void rcu_sysidle_check_cpu(struct rcu_data *rdp, bool *isidle,
unsigned long j;
struct rcu_dynticks *rdtp = rdp->dynticks;
RCU_LOCKDEP_WARN(!irqs_disabled(), "rcu_sysidle_check_cpu() invoked with irqs enabled!!!");
/* If there are no nohz_full= CPUs, don't check system-wide idleness. */
if (!tick_nohz_full_enabled())
return;
@ -2842,6 +2857,8 @@ bool rcu_sys_is_idle(void)
static struct rcu_sysidle_head rsh;
int rss = READ_ONCE(full_sysidle_state);
RCU_LOCKDEP_WARN(!irqs_disabled(), "rcu_sys_is_idle() invoked with irqs enabled!!!");
if (WARN_ON_ONCE(smp_processor_id() != tick_do_timer_cpu))
return false;