From 65bfdd36c113f5d579a382d8f2847210ea4cdca6 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Wed, 2 Jun 2021 16:31:38 -0700 Subject: [PATCH] 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: Paul E. McKenney --- include/linux/srcutiny.h | 8 ++++---- kernel/rcu/srcutiny.c | 2 +- 2 files changed, 5 insertions(+), 5 deletions(-) diff --git a/include/linux/srcutiny.h b/include/linux/srcutiny.h index 0e0cf4d..6cfaa0a 100644 --- a/include/linux/srcutiny.h +++ b/include/linux/srcutiny.h @@ -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 diff --git a/kernel/rcu/srcutiny.c b/kernel/rcu/srcutiny.c index 26344dc..a0ba2ed49 100644 --- a/kernel/rcu/srcutiny.c +++ b/kernel/rcu/srcutiny.c @@ -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)) -- 2.7.4