Messages in this thread | | | Date | Tue, 5 Sep 2023 08:51:52 -1000 | From | Tejun Heo <> | Subject | Re: [PATCH] workqueue: Fix UAF report by KASAN in pwq_release_workfn() |
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Hello,
On Sat, Sep 02, 2023 at 07:50:26PM +0800, Zqiang wrote: > diff --git a/kernel/workqueue.c b/kernel/workqueue.c > index c85825e17df8..f3f9c9222070 100644 > --- a/kernel/workqueue.c > +++ b/kernel/workqueue.c > @@ -4609,6 +4609,10 @@ static int alloc_and_link_pwqs(struct workqueue_struct *wq) > free_percpu(wq->cpu_pwq); > wq->cpu_pwq = NULL; > } > + wq_unregister_lockdep(wq); > + wq_free_lockdep(wq); > + free_workqueue_attrs(wq->unbound_attrs); > + kfree(wq);
So, this would fix the bug but it's quite confusing because we end up taking two separate error handling paths and alloc_and_link_pwqs() ends up freeing stuff allocated outside the function. Wouldn't it be enough to flush the pwq_release_worker after apply_workqueue_attrs() failure so that the cleanup operation ordering is maintained?
Thanks.
-- tejun
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