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| author | Li Zefan <lizefan@huawei.com> | 2014-02-17 10:41:50 +0800 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2014-02-18 18:20:09 -0500 |
| commit | dc5736ed7aaf942caaac0c15af74a018e04ec79d (patch) | |
| tree | 173eb94ee590ef0ba1ab295a49304a0fd1f8a4c2 | |
| parent | cc045e3952175e84c38dad22dea14465b9fc8fb5 (diff) | |
| download | linux-stable-dc5736ed7aaf942caaac0c15af74a018e04ec79d.tar.gz linux-stable-dc5736ed7aaf942caaac0c15af74a018e04ec79d.tar.bz2 linux-stable-dc5736ed7aaf942caaac0c15af74a018e04ec79d.zip | |
cgroup: add a validation check to cgroup_add_cftyps()
Fengguang reported this bug:
BUG: unable to handle kernel NULL pointer dereference at 0000003c
IP: [<cc90b4ad>] cgroup_cfts_commit+0x27/0x1c1
...
Call Trace:
[<cc9d1129>] ? kmem_cache_alloc_trace+0x33f/0x3b7
[<cc90c6fc>] cgroup_add_cftypes+0x8f/0xca
[<cd78b646>] cgroup_init+0x6a/0x26a
[<cd764d7d>] start_kernel+0x4d7/0x57a
[<cd7642ef>] i386_start_kernel+0x92/0x96
This happens in a corner case. If CGROUP_SCHED=y but CFS_BANDWIDTH=n &&
FAIR_GROUP_SCHED=n && RT_GROUP_SCHED=n, we have:
cpu_files[] = {
{ } /* terminate */
}
When we pass cpu_files to cgroup_apply_cftypes(), as cpu_files[0].ss
is NULL, we'll access NULL pointer.
The bug was introduced by commit de00ffa56ea3132c6013fc8f07133b8a1014cf53
("cgroup: make cgroup_subsys->base_cftypes use cgroup_add_cftypes()").
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
| -rw-r--r-- | kernel/cgroup.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 3fe01102607b..771d1b8aaae9 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -2348,6 +2348,9 @@ int cgroup_add_cftypes(struct cgroup_subsys *ss, struct cftype *cfts) { int ret; + if (!cfts || cfts[0].name[0] == '\0') + return 0; + ret = cgroup_init_cftypes(ss, cfts); if (ret) return ret; |