On Thu, 2020-05-21 at 16:51 -0400, Daniel Jordan wrote:
From: Mathias Krause minipli@googlemail.com
[ Upstream commit 1bd845bcb41d5b7f83745e0cb99273eb376f2ec5 ]
Well spotted, I'll add this for 3.16 as well.
Ben.
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@googlemail.com Signed-off-by: Herbert Xu herbert@gondor.apana.org.au Signed-off-by: Daniel Jordan daniel.m.jordan@oracle.com
kernel/padata.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/kernel/padata.c b/kernel/padata.c index 8aef48c3267b..4f860043a8e5 100644 --- a/kernel/padata.c +++ b/kernel/padata.c @@ -461,8 +461,14 @@ 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++;