Messages in this thread | | | Date | Mon, 30 Oct 2017 07:59:36 -0700 | From | Tejun Heo <> | Subject | Re: [PATCH v2] workqueue: Fix NULL pointer dereference |
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On Sat, Oct 28, 2017 at 11:07:28AM +0800, Li Bin wrote: > When queue_work() is used in irq (not in task context), there is > a potential case that trigger NULL pointer dereference. > ---------------------------------------------------------------- > worker_thread() > |-spin_lock_irq() > |-process_one_work() > |-worker->current_pwq = pwq > |-spin_unlock_irq() > |-worker->current_func(work) > |-spin_lock_irq() > |-worker->current_pwq = NULL > |-spin_unlock_irq() > > //interrupt here > |-irq_handler > |-__queue_work() > //assuming that the wq is draining > |-is_chained_work(wq) > |-current_wq_worker() > //Here, 'current' is the interrupted worker! > |-current->current_pwq is NULL here! > |-schedule() > ---------------------------------------------------------------- > > Avoid it by checking for task context in current_wq_worker(), and > if not in task context, we shouldn't use the 'current' to check the > condition. > > Reported-by: Xiaofei Tan <tanxiaofei@huawei.com> > Signed-off-by: Li Bin <huawei.libin@huawei.com>
Applied to wq/for-4.14-fixes w/ -stable cc'd.
Thanks.
-- tejun
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