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| author | Li Zefan <lizefan@huawei.com> | 2013-03-05 10:57:03 +0800 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2013-03-05 09:33:25 -0800 |
| commit | 7d8e0bf56a66bab08d2f316dd87e56c08cecb899 (patch) | |
| tree | be35c2daec953f0c98241c16311879dd45bc4859 /include | |
| parent | f50daa704f36a6544a902c52b6cf37b0493dfc5d (diff) | |
| download | linux-7d8e0bf56a66bab08d2f316dd87e56c08cecb899.tar.gz linux-7d8e0bf56a66bab08d2f316dd87e56c08cecb899.tar.bz2 linux-7d8e0bf56a66bab08d2f316dd87e56c08cecb899.zip | |
cgroup: avoid accessing modular cgroup subsys structure without locking
subsys[i] is set to NULL in cgroup_unload_subsys() at modular unload,
and that's protected by cgroup_mutex, and then the memory *subsys[i]
resides will be freed.
So this is unsafe without any locking:
if (!ss || ss->module)
...
v2:
- add a comment for enum cgroup_subsys_id
- simplify the comment in cgroup_exit()
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/cgroup.h | 17 |
1 files changed, 14 insertions, 3 deletions
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index 75c6ec1ba1ba..5f76829dd75e 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -44,14 +44,25 @@ extern void cgroup_unload_subsys(struct cgroup_subsys *ss); extern const struct file_operations proc_cgroup_operations; -/* Define the enumeration of all builtin cgroup subsystems */ +/* + * Define the enumeration of all cgroup subsystems. + * + * We define ids for builtin subsystems and then modular ones. + */ #define SUBSYS(_x) _x ## _subsys_id, -#define IS_SUBSYS_ENABLED(option) IS_ENABLED(option) enum cgroup_subsys_id { +#define IS_SUBSYS_ENABLED(option) IS_BUILTIN(option) +#include <linux/cgroup_subsys.h> +#undef IS_SUBSYS_ENABLED + CGROUP_BUILTIN_SUBSYS_COUNT, + + __CGROUP_SUBSYS_TEMP_PLACEHOLDER = CGROUP_BUILTIN_SUBSYS_COUNT - 1, + +#define IS_SUBSYS_ENABLED(option) IS_MODULE(option) #include <linux/cgroup_subsys.h> +#undef IS_SUBSYS_ENABLED CGROUP_SUBSYS_COUNT, }; -#undef IS_SUBSYS_ENABLED #undef SUBSYS /* Per-subsystem/per-cgroup state maintained by the system. */ |