| Message ID | 20230510165832.2187453-6-paulmck@kernel.org (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | a24c1aab652ebacf9ea62470a166514174c96fe1 |
| Headers | show |
| Series | Miscellaneous fixes for v6.5 | expand |
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index e2dbea6cee4b..faa1c01d2917 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -2481,12 +2481,12 @@ static void rcu_cpu_kthread(unsigned int cpu) *statusp = RCU_KTHREAD_RUNNING; local_irq_disable(); work = *workp; - *workp = 0; + WRITE_ONCE(*workp, 0); local_irq_enable(); if (work) rcu_core(); local_bh_enable(); - if (*workp == 0) { + if (!READ_ONCE(*workp)) { trace_rcu_utilization(TPS("End CPU kthread@rcu_wait")); *statusp = RCU_KTHREAD_WAITING; return;
The rcu_data structure's ->rcu_cpu_has_work field can be modified by any CPU attempting to wake up the rcuc kthread. Therefore, this commit marks accesses to this field from the rcu_cpu_kthread() function. This data race was reported by KCSAN. Not appropriate for backporting due to failure being unlikely. Signed-off-by: Paul E. McKenney <paulmck@kernel.org> --- kernel/rcu/tree.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)