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author | Li Bin <huawei.libin@huawei.com> | 2017-10-28 11:07:28 +0800 |
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committer | Tejun Heo <tj@kernel.org> | 2017-10-30 07:56:01 -0700 |
commit | cef572ad9bd7f85035ba8272e5352040e8be0152 (patch) | |
tree | a324f1e505d3698cd0df3d22898f1c5c5e68370d /kernel/workqueue_internal.h | |
parent | 692b48258dda7c302e777d7d5f4217244478f1f6 (diff) | |
download | linux-cef572ad9bd7f85035ba8272e5352040e8be0152.tar.gz |
workqueue: Fix NULL pointer dereference
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()") Cc: stable@vger.kernel.org # v3.9+
Diffstat (limited to 'kernel/workqueue_internal.h')
-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 8635417c587b..29fa81f0f51a 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; } |