From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:49136 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752992AbdKJNoA (ORCPT ); Fri, 10 Nov 2017 08:44:00 -0500 Subject: Patch "workqueue: Fix NULL pointer dereference" has been added to the 3.18-stable tree To: huawei.libin@huawei.com Cc: , From: Date: Fri, 10 Nov 2017 14:44:01 +0100 Message-ID: <15103214411129@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled workqueue: Fix NULL pointer dereference to the 3.18-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: workqueue-fix-null-pointer-dereference.patch and it can be found in the queue-3.18 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From cef572ad9bd7f85035ba8272e5352040e8be0152 Mon Sep 17 00:00:00 2001 From: Li Bin Date: Sat, 28 Oct 2017 11:07:28 +0800 Subject: workqueue: Fix NULL pointer dereference From: Li Bin 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 Signed-off-by: Li Bin Reviewed-by: Lai Jiangshan Signed-off-by: Tejun Heo Fixes: 8d03ecfe4718 ("workqueue: reimplement is_chained_work() using current_wq_worker()") Signed-off-by: Greg Kroah-Hartman --- kernel/workqueue_internal.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/kernel/workqueue_internal.h +++ b/kernel/workqueue_internal.h @@ -9,6 +9,7 @@ #include #include +#include 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; } Patches currently in stable-queue which might be from huawei.libin@huawei.com are queue-3.18/workqueue-fix-null-pointer-dereference.patch