On Mon, Dec 25, 2006 at 11:41:32AM +0200, Muli Ben-Yehuda wrote:
> On Mon, Dec 25, 2006 at 06:35:57PM +0900, Akinobu Mita wrote:
> > On Mon, Dec 25, 2006 at 10:55:51AM +0200, Muli Ben-Yehuda wrote:
> > > This is correct because cct is allocated via alloc_percpu, which in
> > > turn calls kzalloc, which means cct->task is NULL by default, but it's
> > > a little too obscure for me. How about making it explicit?
> > >
> > > task = kthread_create(...)
> > > if (!IS_ERR(task))
> > > cct->task = task;
> > > else
> > > cct->task = NULL;
> > >
> > > return cct->task;
> >
> > Subject: [PATCH -mm] ehca: avoid crash on kthread_create() failure (v3)
> >
> > 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
> > @@ -606,15 +606,20 @@ 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;
> > + else
> > + cct->task = NULL;
> >
> > - return cct->task;
> > + return task;
>
> This should be return cct->task, since we later test the return value
> of create_comp_task against NULL, e.g., in comp_poll_callback and
> ehca_create_comp_pool.
Yeah, I already sent the patch:
http://lkml.org/lkml/2006/12/19/56
Maybe I should reorganize these ehca fixes later.
(make ehca_create_task() return NULL on failure)
-
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