Messages in this thread Patch in this message |  | | Date | Thu, 12 Dec 2013 22:37:32 +0400 | From | Vladimir Davydov <> | Subject | Re: [PATCH] cgroup: fix fail path in cgroup_load_subsys() |
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On 12/12/2013 07:55 PM, Tejun Heo wrote: > On Thu, Dec 12, 2013 at 10:35:36AM -0500, Tejun Heo wrote: >> On Sat, Dec 07, 2013 at 11:58:05AM +0400, Vladimir Davydov wrote: >>> We should not call cgroup_unload_subsys() if online_css() fails, because >>> online_css() does not assign css to cgroup on failure, while >>> offline_css() called from cgroup_unload_subsys() expects it is assigned. >>> So let's call everything we need to rollback inline without involving >>> cgroup_unload_subsys(). >>> >>> Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> >>> Cc: Tejun Heo <tj@kernel.org> >>> Cc: Li Zefan <lizefan@huawei.com> >> Applied to cgroup/for-3.13-fixes. > Scrap that. I don't think we can fail css_online for the root css in > 3.13-fixes and this would cause conflict with 3.14, so let's not > commit it to 3.13-fixes. Vladimir, can you please respin the patch on > top of cgroup/for-3.14
No problem.
> but make cgroup_unload_subsys() check whether > css is actually there before calling offline so that it matches the > usual offline path better?
You want me to add something like this to the patch, don't you?
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 402f7aa..bc03b97 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -4680,6 +4680,7 @@ EXPORT_SYMBOL_GPL(cgroup_load_subsys); void cgroup_unload_subsys(struct cgroup_subsys *ss) { struct cgrp_cset_link *link; + struct cgroup_subsys_state *css; BUG_ON(ss->module == NULL); @@ -4693,7 +4694,9 @@ void cgroup_unload_subsys(struct cgroup_subsys *ss) mutex_lock(&cgroup_mutex); mutex_lock(&cgroup_root_mutex); - offline_css(cgroup_css(cgroup_dummy_top, ss)); + css = cgroup_css(cgroup_dummy_top, ss); + if (css) + offline_css(css); /* deassign the subsys_id */ cgroup_subsys[ss->subsys_id] = NULL;
If so, I don't mind, but why? cgroup_unload_subsys() should never be called without properly initialized css.
Thanks.
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