On Thu, Dec 21, 2006 at 10:22:02PM +0100, Heiko Carstens wrote:
> > Index: 2.6-mm/drivers/infiniband/hw/ehca/ehca_irq.c
> > ===================================================================
> > --- 2.6-mm.orig/drivers/infiniband/hw/ehca/ehca_irq.c
> > +++ 2.6-mm/drivers/infiniband/hw/ehca/ehca_irq.c
> > @@ -670,11 +670,13 @@ static int comp_pool_callback(struct not
> > {
> > unsigned int cpu = (unsigned long)hcpu;
> > struct ehca_cpu_comp_task *cct;
> > + struct task_struct *task;
> >
> > switch (action) {
> > case CPU_UP_PREPARE:
> > ehca_gen_dbg("CPU: %x (CPU_PREPARE)", cpu);
> > - if(!create_comp_task(pool, cpu)) {
> > + task = create_comp_task(pool, cpu);
> > + if (IS_ERR(task)) {
> > ehca_gen_err("Can't create comp_task for cpu: %x", cpu);
> > return NOTIFY_BAD;
> > }
>
> If this fails then the code will crash on CPU_UP_CANCELED. Because of
> kthread_bind(cct->task,...). cct->task would be just the encoded error
> number.
Subject: [PATCH -mm] ehca: avoid crash on kthread_create() failure
This patch disallows invalid task_struct pointer returned by
kthread_create() to be written to percpu data to avoid crash.
Cc: Heiko Carstens <[email protected]>
Cc: Hoang-Nam Nguyen <[email protected]>
Cc: Christoph Raisch <[email protected]>
Signed-off-by: Akinobu Mita <[email protected]>
---
drivers/infiniband/hw/ehca/ehca_irq.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
Index: 2.6-mm/drivers/infiniband/hw/ehca/ehca_irq.c
===================================================================
--- 2.6-mm.orig/drivers/infiniband/hw/ehca/ehca_irq.c
+++ 2.6-mm/drivers/infiniband/hw/ehca/ehca_irq.c
@@ -606,13 +606,16 @@ static int comp_task(void *__cct)
static struct task_struct *create_comp_task(struct ehca_comp_pool *pool,
int cpu)
{
+ struct task_struct *task;
struct ehca_cpu_comp_task *cct;
cct = per_cpu_ptr(pool->cpu_comp_tasks, cpu);
spin_lock_init(&cct->task_lock);
INIT_LIST_HEAD(&cct->cq_list);
init_waitqueue_head(&cct->wait_queue);
- cct->task = kthread_create(comp_task, cct, "ehca_comp/%d", cpu);
+ task = kthread_create(comp_task, cct, "ehca_comp/%d", cpu);
+ if (!IS_ERR(task))
+ cct->task = task;
return cct->task;
}
@@ -684,8 +687,10 @@ static int comp_pool_callback(struct not
case CPU_UP_CANCELED:
ehca_gen_dbg("CPU: %x (CPU_CANCELED)", cpu);
cct = per_cpu_ptr(pool->cpu_comp_tasks, cpu);
- kthread_bind(cct->task, any_online_cpu(cpu_online_map));
- destroy_comp_task(pool, cpu);
+ if (cct->task) {
+ kthread_bind(cct->task, any_online_cpu(cpu_online_map));
+ destroy_comp_task(pool, cpu);
+ }
break;
case CPU_ONLINE:
ehca_gen_dbg("CPU: %x (CPU_ONLINE)", cpu);
-
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