| Message ID | 20200521205145.1953392-1-daniel.m.jordan@oracle.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Delegated to: | Herbert Xu |
| Headers | show |
| Series | [stable-4.4,1/5] padata: set cpu_index of unused CPUs to -1 | expand |
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++;
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++;