lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Thu, 20 Feb 2014 10:01:03 +0800 From: Lai Jiangshan <laijs@...fujitsu.com> To: Tejun Heo <tj@...nel.org> CC: linux-kernel@...r.kernel.org Subject: Re: [PATCH] workqueue: Fix possible unexpectedly worker wakeup before started On 02/20/2014 09:50 AM, Lai Jiangshan wrote: > On 02/20/2014 08:11 AM, Tejun Heo wrote: >> Hello, Lai. >> >> On Wed, Feb 19, 2014 at 11:47:58AM +0800, Lai Jiangshan wrote: >>> If a worker is wokenup unexpectedly, it will start to work incorretly. >>> Although it hardly happen, we should catch it and wait for being started >>> if it does happen. >> >> Can this actually happen? If so, how? > > I don't think it can happen. > It depends on the system outside of workqueue. > > I'm afraid someone see the task and wake up it. > workqueue protect itself. I was extremely nervously, please drop the patch. I also don't like too much protective code in workqueue. > >> >>> Signed-off-by: Lai Jiangshan <laijs@...fujitsu.com> >>> --- >>> kernel/workqueue.c | 6 ++++++ >>> 1 files changed, 6 insertions(+), 0 deletions(-) >>> >>> diff --git a/kernel/workqueue.c b/kernel/workqueue.c >>> index 82ef9f3..bee5fe1 100644 >>> --- a/kernel/workqueue.c >>> +++ b/kernel/workqueue.c >>> @@ -2284,6 +2284,12 @@ static int worker_thread(void *__worker) >>> struct worker *worker = __worker; >>> struct worker_pool *pool = worker->pool; >>> >>> + if (WARN_ON_ONCE(!(worker->flags & WORKER_STARTED))) { >> >> And if this is something which can legitimately happen, why are we >> triggering WARN on it? > > If it happens, it means there is something wrong in the system. > >> >>> + /* The worker is wokenup unexpectedly before started */ >>> + mutex_lock(&pool->manager_mutex); >>> + mutex_unlock(&pool->manager_mutex); >> >> And what does these mutex cycling achieve (they need comment)? > > Synchronize the manager to finish. > >> >> Thanks. >> > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@...r.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists