The parallel queue per-cpu data structure gets initialized only for CPUs
in the 'pcpu' CPU mask set. This is not sufficient as the reorder timer
may run on a different CPU and might wrongly decide it's the target CPU
for the next reorder item as per-cpu memory gets memset(0) and we might
be waiting for the first CPU in cpumask.pcpu, i.e. cpu_index 0.
Make the '__this_cpu_read(pd->pqueue->cpu_index) == next_queue->cpu_index'
compare in padata_get_next() fail in this case by initializing the
cpu_index member of all per-cpu parallel queues. Use -1 for unused ones.
Signed-off-by: Mathias Krause <minipli@xxxxxxxxxxxxxx>
---
kernel/padata.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/kernel/padata.c b/kernel/padata.c
index 868f947166d7..1b9b4bac4a9b 100644
--- a/kernel/padata.c
+++ b/kernel/padata.c
@@ -384,8 +384,14 @@ static void padata_init_pqueues(struct parallel_data *pd)
struct padata_parallel_queue *pqueue;
cpu_index = 0;
- for_each_cpu(cpu, pd->cpumask.pcpu) {
+ for_each_possible_cpu(cpu) {
pqueue = per_cpu_ptr(pd->pqueue, cpu);
+
+ if (!cpumask_test_cpu(cpu, pd->cpumask.pcpu)) {
+ pqueue->cpu_index = -1;
+ continue;
+ }
+
pqueue->pd = pd;
pqueue->cpu_index = cpu_index;
cpu_index++;
--
1.7.10.4
