[PATCH 10/17] cgroup: fix harmless bugs in cgroup_load_subsys() fail path and cgroup_unload_subsys()
From: Tejun Heo <hidden>
Date: 2012-11-13 03:04:33
Also in:
lkml
Subsystem:
the rest · Maintainer:
Linus Torvalds
* If idr init fails, cgroup_load_subsys() cleared dummytop->subsys[] before calilng ->destroy() making CSS inaccessible to the callback, and didn't unlink ss->sibling. As no modular controller uses ->use_id, this doesn't cause any actual problems. * cgroup_unload_subsys() was forgetting to free idr, call ->pre_destroy() and clear ->active. As there currently is no modular controller which uses ->use_id, ->pre_destroy() or ->active, this doesn't cause any actual problems. Signed-off-by: Tejun Heo <redacted> --- kernel/cgroup.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-)
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 76f1a01..c5368c0 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c@@ -4420,9 +4420,10 @@ int __init_or_module cgroup_load_subsys(struct cgroup_subsys *ss) if (ss->use_id) { int ret = cgroup_init_idr(ss, css); if (ret) { - dummytop->subsys[ss->subsys_id] = NULL; ss->destroy(dummytop); + dummytop->subsys[ss->subsys_id] = NULL; subsys[ss->subsys_id] = NULL; + list_del_init(&ss->sibling); mutex_unlock(&cgroup_mutex); return ret; }
@@ -4490,7 +4491,19 @@ void cgroup_unload_subsys(struct cgroup_subsys *ss) */ BUG_ON(ss->root != &rootnode); + /* ->pre_destroy() should be called outside cgroup_mutex for now */ + if (ss->pre_destroy) + ss->pre_destroy(dummytop); + mutex_lock(&cgroup_mutex); + + ss->active = 0; + + if (ss->use_id) { + idr_remove_all(&ss->idr); + idr_destroy(&ss->idr); + } + /* deassign the subsys_id */ subsys[ss->subsys_id] = NULL;
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1.7.11.7