Commit 65bfdd36 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

srcutiny: Mark read-side data races 



This commit marks some interrupt-induced read-side data races in
__srcu_read_lock(), __srcu_read_unlock(), and srcu_torture_stats_print().

Signed-off-by: default avatarPaul E. McKenney <paulmck@kernel.org>
parent b169246f

include/linux/srcutiny.h

+4 −4
Original line number Diff line number Diff line
@@ -61,7 +61,7 @@ static inline int __srcu_read_lock(struct srcu_struct *ssp) 
	int idx;



	idx = ((READ_ONCE(ssp->srcu_idx) + 1) & 0x2) >> 1;

	WRITE_ONCE(ssp->srcu_lock_nesting[idx], ssp->srcu_lock_nesting[idx] + 1);

	WRITE_ONCE(ssp->srcu_lock_nesting[idx], READ_ONCE(ssp->srcu_lock_nesting[idx]) + 1);

	return idx;

}
@@ -81,11 +81,11 @@ static inline void srcu_torture_stats_print(struct srcu_struct *ssp, 
{

	int idx;



	idx = ((READ_ONCE(ssp->srcu_idx) + 1) & 0x2) >> 1;

	idx = ((data_race(READ_ONCE(ssp->srcu_idx)) + 1) & 0x2) >> 1;

	pr_alert("%s%s Tiny SRCU per-CPU(idx=%d): (%hd,%hd)\n",

		 tt, tf, idx,

		 READ_ONCE(ssp->srcu_lock_nesting[!idx]),

		 READ_ONCE(ssp->srcu_lock_nesting[idx]));

		 data_race(READ_ONCE(ssp->srcu_lock_nesting[!idx])),

		 data_race(READ_ONCE(ssp->srcu_lock_nesting[idx])));

}



#endif

kernel/rcu/srcutiny.c

+1 −1
Original line number Diff line number Diff line
@@ -96,7 +96,7 @@ EXPORT_SYMBOL_GPL(cleanup_srcu_struct); 
 */

void __srcu_read_unlock(struct srcu_struct *ssp, int idx)

{

	int newval = ssp->srcu_lock_nesting[idx] - 1;

	int newval = READ_ONCE(ssp->srcu_lock_nesting[idx]) - 1;



	WRITE_ONCE(ssp->srcu_lock_nesting[idx], newval);

	if (!newval && READ_ONCE(ssp->srcu_gp_waiting))