Messages in this thread | | | Date | Fri, 25 Oct 2019 19:05:25 +0200 | From | Christian Brauner <> | Subject | Re: [PATCH cgroup/for-5.5] cgroup: remove cgroup_enable_task_cg_lists() optimization |
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[Removing a few people from Cc to avoid spamming the whole world]
On Fri, Oct 25, 2019 at 05:52:25PM +0200, Oleg Nesterov wrote: > On 10/25, Christian Brauner wrote: > > > > On Fri, Oct 25, 2019 at 04:13:25PM +0200, Oleg Nesterov wrote: > > > Almost every usage of task->flags (load or sore) can be reported as "data race". > > > > > > Say, you do > > > > > > if (task->flags & PF_KTHREAD) > > > > > > while this task does > > > > > > current->flags |= PF_FREEZER_SKIP; > > > schedule(). > > > > > > this is data race. > > > > Right, but I thought we agreed on WONTFIX in those scenarios? > > The alternative is to READ_ONCE()/WRITE_ONCE() all of these. > > Well, in my opinion this is WONTFIX, but I won't argue if someone > adds _ONCE to all of these. Same for task->state, exit_state, and > more.
Well, I honestly think that state and exit_state would make sense. There already were issues that got fixed for example in 3245d6acab98 ("exit: fix race between wait_consider_task() and wait_task_zombie()") and as far as I understand this would also help kcsan to better detect races.
Christian
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