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| author | Vladimir Davydov <vdavydov@parallels.com> | 2013-12-12 23:17:08 +0400 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2013-12-13 15:46:49 -0500 |
| commit | 10bf2f7e7db993273419ca9f51f5934e4cf71768 (patch) | |
| tree | 3d6f820b4409859fc97e4dfc8a3c90d936d27b24 /kernel/cgroup.c | |
| parent | 0be8669dd530f60cf3f59f084518570c1dfb47ee (diff) | |
| download | lwn-10bf2f7e7db993273419ca9f51f5934e4cf71768.tar.gz lwn-10bf2f7e7db993273419ca9f51f5934e4cf71768.zip | |
cgroup: fix fail path in cgroup_load_subsys()
Calling cgroup_unload_subsys() from cgroup_load_subsys() after
online_css() failure will result in a NULL ptr dereference on attempt to
offline_css(), because online_css() only assigns css to cgroup on
success. Let's fix that by skipping calls to offline_css() and
css_free() in cgroup_unload_subsys() if there is no css, and freeing css
in cgroup_load_subsys() on online_css() failure.
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Diffstat (limited to 'kernel/cgroup.c')
| -rw-r--r-- | kernel/cgroup.c | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 402f7aab8b2d..7030f04f2890 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -4652,8 +4652,10 @@ int __init_or_module cgroup_load_subsys(struct cgroup_subsys *ss) write_unlock(&css_set_lock); ret = online_css(css); - if (ret) + if (ret) { + ss->css_free(css); goto err_unload; + } /* success! */ mutex_unlock(&cgroup_root_mutex); @@ -4680,6 +4682,7 @@ 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 +4696,9 @@ 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; @@ -4720,7 +4725,8 @@ void cgroup_unload_subsys(struct cgroup_subsys *ss) * need to free before marking as null because ss->css_free needs * the cgrp->subsys pointer to find their state. */ - ss->css_free(cgroup_css(cgroup_dummy_top, ss)); + if (css) + ss->css_free(css); RCU_INIT_POINTER(cgroup_dummy_top->subsys[ss->subsys_id], NULL); mutex_unlock(&cgroup_root_mutex); |