In function __note_gp_changes(), rdp->gpwrap is read using READ_ONCE() in line 1307: 1307 if (IS_ENABLED(CONFIG_PROVE_RCU) && READ_ONCE(rdp->gpwrap)) 1308 WRITE_ONCE(rdp->last_sched_clock, jiffies); while read directly in line 1305: 1305 if (ULONG_CMP_LT(rdp->gp_seq_needed, rnp->gp_seq_needed) || rdp->gpwrap) 1306 WRITE_ONCE(rdp->gp_seq_needed, rnp->gp_seq_needed); In the same environment, reads in two places should have the same protection. Signed-off-by: Zilin Guan <zilinguan811@xxxxxxxxx> --- kernel/rcu/tree.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index b1f883fcd918..d3e2b420dce5 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -1302,7 +1302,7 @@ static bool __note_gp_changes(struct rcu_node *rnp, struct rcu_data *rdp) zero_cpu_stall_ticks(rdp); } rdp->gp_seq = rnp->gp_seq; /* Remember new grace-period state. */ - if (ULONG_CMP_LT(rdp->gp_seq_needed, rnp->gp_seq_needed) || rdp->gpwrap) + if (ULONG_CMP_LT(rdp->gp_seq_needed, rnp->gp_seq_needed) || READ_ONCE(rdp->gpwrap)) WRITE_ONCE(rdp->gp_seq_needed, rnp->gp_seq_needed); if (IS_ENABLED(CONFIG_PROVE_RCU) && READ_ONCE(rdp->gpwrap)) WRITE_ONCE(rdp->last_sched_clock, jiffies); -- 2.34.1
