The rdp->cpu_no_qs.s field is accessed only by the current CPU, but can be accessed both at task level and from interrupt handlers. All accesses from interrupts-enabled code must therefore be marked. This commit therefore converts from __this_cpu_read() to this_cpu_read(), but only in interrupts-enabled code, that is, the rcu_qs() function.
KCSAN located this issue. Signed-off-by: Paul E. McKenney <[email protected]> --- kernel/rcu/tree_plugin.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index 844a9ced67cc0e..6904a4f826d1ea 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -976,7 +976,7 @@ static void __init rcu_bootup_announce(void) static void rcu_qs(void) { RCU_LOCKDEP_WARN(preemptible(), "rcu_qs() invoked with preemption enabled!!!"); - if (!__this_cpu_read(rcu_data.cpu_no_qs.s)) + if (!this_cpu_read(rcu_data.cpu_no_qs.s)) return; trace_rcu_grace_period(TPS("rcu_sched"), __this_cpu_read(rcu_data.gp_seq), TPS("cpuqs")); -- 2.40.1
