From: Steffen Klassert on
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(a)secunet.com>
---
kernel/padata.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/kernel/padata.c b/kernel/padata.c
index 6a51945..7f895e2 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))
--
1.5.6.5

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