diff options
| author | Li Bin <huawei.libin@huawei.com> | 2017-10-28 11:07:28 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-11-15 17:13:11 +0100 |
| commit | 44540ead8a8a159a4d2a9cb2e3e0b7388cfaa3b1 (patch) | |
| tree | 2fb95c17ead800b8bd3c773d2ac098a961b4af70 /kernel | |
| parent | ad8c619750c499f68f99f0bccb1a12114b7f2033 (diff) | |
workqueue: Fix NULL pointer dereference
commit cef572ad9bd7f85035ba8272e5352040e8be0152 upstream.
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>
Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Fixes: 8d03ecfe4718 ("workqueue: reimplement is_chained_work() using current_wq_worker()")
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/workqueue_internal.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/kernel/workqueue_internal.h b/kernel/workqueue_internal.h index 45215870ac6c..3fa9c146fccb 100644 --- a/kernel/workqueue_internal.h +++ b/kernel/workqueue_internal.h @@ -9,6 +9,7 @@ #include <linux/workqueue.h> #include <linux/kthread.h> +#include <linux/preempt.h> struct worker_pool; @@ -59,7 +60,7 @@ struct worker { */ static inline struct worker *current_wq_worker(void) { - if (current->flags & PF_WQ_WORKER) + if (in_task() && (current->flags & PF_WQ_WORKER)) return kthread_data(current); return NULL; } |