From 3047817b894ddae62be07787bc8735a616104398 Mon Sep 17 00:00:00 2001 From: Steffen Klassert Date: Fri, 9 Mar 2012 07:20:12 +0100 Subject: [PATCH] padata: Fix race in the serialization path When a padata object is queued to the serialization queue, another cpu might process and free the padata object. So don't dereference it after queueing to the serialization queue. Signed-off-by: Steffen Klassert Signed-off-by: Herbert Xu --- kernel/padata.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/kernel/padata.c b/kernel/padata.c index b45259931512..aa9929545855 100644 --- a/kernel/padata.c +++ b/kernel/padata.c @@ -230,6 +230,7 @@ out: static void padata_reorder(struct parallel_data *pd) { + int cb_cpu; struct padata_priv *padata; struct padata_serial_queue *squeue; struct padata_instance *pinst = pd->pinst; @@ -270,13 +271,14 @@ static void padata_reorder(struct parallel_data *pd) return; } - squeue = per_cpu_ptr(pd->squeue, padata->cb_cpu); + cb_cpu = padata->cb_cpu; + squeue = per_cpu_ptr(pd->squeue, cb_cpu); spin_lock(&squeue->serial.lock); list_add_tail(&padata->list, &squeue->serial.list); spin_unlock(&squeue->serial.lock); - queue_work_on(padata->cb_cpu, pinst->wq, &squeue->work); + queue_work_on(cb_cpu, pinst->wq, &squeue->work); } spin_unlock_bh(&pd->lock); -- 2.20.1