padata: Check for valid cpumasks

Now that we allow to change the cpumasks from userspace, we have
to check for valid cpumasks in padata_do_parallel. This patch adds
the necessary check. This fixes a division by zero crash if the
parallel cpumask contains no active cpu.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 1 insertions, 1 deletions

diff --git a/kernel/padata.c b/kernel/padata.c
index 6a519454a5bd..7f895e2b4efb 100644
--- a/kernel/padata.c
+++ b/kernel/padata.c
@@ -114,7 +114,7 @@ int padata_do_parallel(struct padata_instance *pinst,
         pd = rcu_dereference(pinst->pd);
 
         err = -EINVAL;
-        if (!(pinst->flags & PADATA_INIT))
+        if (!(pinst->flags & PADATA_INIT) || pinst->flags & PADATA_INVALID)
                 goto out;
 
         if (!cpumask_test_cpu(cb_cpu, pd->cpumask.cbcpu))