Once stop_machine() is gone from the CPU offline path, we won't be able
to depend on disabling preemption to prevent CPUs from going offline
from under us.
Use the get/put_online_cpus_atomic() APIs to prevent CPUs from going
offline, while invoking from atomic context.
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Sedat Dilek <sedat.dilek@xxxxxxxxx>
Cc: "Paul E. McKenney" <paulmck@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@xxxxxxxxxxxxxxxxxx>
---
kernel/softirq.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/kernel/softirq.c b/kernel/softirq.c
index 3d6833f..c289722 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -644,14 +644,17 @@ static void remote_softirq_receive(void *data)
static int __try_remote_softirq(struct call_single_data *cp, int cpu, int softirq)
{
+ get_online_cpus_atomic();
if (cpu_online(cpu)) {
cp->func = remote_softirq_receive;
cp->info = &softirq;
cp->flags = 0;
__smp_call_function_single(cpu, cp, 0);
+ put_online_cpus_atomic();
return 0;
}
+ put_online_cpus_atomic();
return 1;
}
#else /* CONFIG_USE_GENERIC_SMP_HELPERS */
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