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Commit fe15d706 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

rcu: Add lockdep-RCU checks for simple self-deadlock 



It is illegal to have a grace period within a same-flavor RCU read-side
critical section, so this commit adds lockdep-RCU checks to splat when
such abuse is encountered.  This commit does not detect more elaborate
RCU deadlock situations.  These situations might be a job for lockdep
enhancements.

Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent 18fec7d8

kernel/rcutiny.c

+4 −0
Original line number Original line Diff line number Diff line
@@ -319,6 +319,10 @@ static void rcu_process_callbacks(struct softirq_action *unused) 
 */

 */

void synchronize_sched(void)

void synchronize_sched(void)

{

{

	rcu_lockdep_assert(!lock_is_held(&rcu_bh_lock_map) &&

			   !lock_is_held(&rcu_lock_map) &&

			   !lock_is_held(&rcu_sched_lock_map),

			   "Illegal synchronize_sched() in RCU read-side critical section");

	cond_resched();

	cond_resched();

}

}

EXPORT_SYMBOL_GPL(synchronize_sched);

EXPORT_SYMBOL_GPL(synchronize_sched);

kernel/rcutiny_plugin.h

+5 −0
Original line number Original line Diff line number Diff line
@@ -706,6 +706,11 @@ EXPORT_SYMBOL_GPL(call_rcu); 
 */

 */

void synchronize_rcu(void)

void synchronize_rcu(void)

{

{

	rcu_lockdep_assert(!lock_is_held(&rcu_bh_lock_map) &&

			   !lock_is_held(&rcu_lock_map) &&

			   !lock_is_held(&rcu_sched_lock_map),

			   "Illegal synchronize_rcu() in RCU read-side critical section");



#ifdef CONFIG_DEBUG_LOCK_ALLOC

#ifdef CONFIG_DEBUG_LOCK_ALLOC

	if (!rcu_scheduler_active)

	if (!rcu_scheduler_active)

		return;

		return;

kernel/rcutree.c

+8 −0
Original line number Original line Diff line number Diff line
@@ -1816,6 +1816,10 @@ EXPORT_SYMBOL_GPL(call_rcu_bh); 
 */

 */

void synchronize_sched(void)

void synchronize_sched(void)

{

{

	rcu_lockdep_assert(!lock_is_held(&rcu_bh_lock_map) &&

			   !lock_is_held(&rcu_lock_map) &&

			   !lock_is_held(&rcu_sched_lock_map),

			   "Illegal synchronize_sched() in RCU-sched read-side critical section");

	if (rcu_blocking_is_gp())

	if (rcu_blocking_is_gp())

		return;

		return;

	wait_rcu_gp(call_rcu_sched);

	wait_rcu_gp(call_rcu_sched);
@@ -1833,6 +1837,10 @@ EXPORT_SYMBOL_GPL(synchronize_sched); 
 */

 */

void synchronize_rcu_bh(void)

void synchronize_rcu_bh(void)

{

{

	rcu_lockdep_assert(!lock_is_held(&rcu_bh_lock_map) &&

			   !lock_is_held(&rcu_lock_map) &&

			   !lock_is_held(&rcu_sched_lock_map),

			   "Illegal synchronize_rcu_bh() in RCU-bh read-side critical section");

	if (rcu_blocking_is_gp())

	if (rcu_blocking_is_gp())

		return;

		return;

	wait_rcu_gp(call_rcu_bh);

	wait_rcu_gp(call_rcu_bh);

kernel/rcutree_plugin.h

+4 −0
Original line number Original line Diff line number Diff line
@@ -688,6 +688,10 @@ EXPORT_SYMBOL_GPL(call_rcu); 
 */

 */

void synchronize_rcu(void)

void synchronize_rcu(void)

{

{

	rcu_lockdep_assert(!lock_is_held(&rcu_bh_lock_map) &&

			   !lock_is_held(&rcu_lock_map) &&

			   !lock_is_held(&rcu_sched_lock_map),

			   "Illegal synchronize_rcu() in RCU read-side critical section");

	if (!rcu_scheduler_active)

	if (!rcu_scheduler_active)

		return;

		return;

	wait_rcu_gp(call_rcu);

	wait_rcu_gp(call_rcu);

kernel/srcu.c

+6 −0
Original line number Original line Diff line number Diff line
@@ -172,6 +172,12 @@ static void __synchronize_srcu(struct srcu_struct *sp, void (*sync_func)(void)) 
{

{

	int idx;

	int idx;





	rcu_lockdep_assert(!lock_is_held(&sp->dep_map) &&

			   !lock_is_held(&rcu_bh_lock_map) &&

			   !lock_is_held(&rcu_lock_map) &&

			   !lock_is_held(&rcu_sched_lock_map),

			   "Illegal synchronize_srcu() in same-type SRCU (or RCU) read-side critical section");



	idx = sp->completed;

	idx = sp->completed;

	mutex_lock(&sp->mutex);

	mutex_lock(&sp->mutex);