diff options
| author | Lai Jiangshan <laijs@cn.fujitsu.com> | 2008-10-18 20:28:03 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-10-20 08:52:38 -0700 |
| commit | 146aa1bd0511f88ddb4e92fafa2b8aad4f2f65f3 (patch) | |
| tree | d7deb46b9a38f82f109b2126317899efbbce41c2 /include/linux | |
| parent | 248736c2a57206388c86f8cdd3392ee986e84f9f (diff) | |
cgroups: fix probable race with put_css_set[_taskexit] and find_css_set
put_css_set_taskexit may be called when find_css_set is called on other
cpu. And the race will occur:
put_css_set_taskexit side find_css_set side
|
atomic_dec_and_test(&kref->refcount) |
/* kref->refcount = 0 */ |
....................................................................
| read_lock(&css_set_lock)
| find_existing_css_set
| get_css_set
| read_unlock(&css_set_lock);
....................................................................
__release_css_set |
....................................................................
| /* use a released css_set */
|
[put_css_set is the same. But in the current code, all put_css_set are
put into cgroup mutex critical region as the same as find_css_set.]
[akpm@linux-foundation.org: repair comments]
[menage@google.com: eliminate race in css_set refcounting]
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/cgroup.h | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index 30934e4bfaa..7166023e07d 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -9,7 +9,6 @@ */ #include <linux/sched.h> -#include <linux/kref.h> #include <linux/cpumask.h> #include <linux/nodemask.h> #include <linux/rcupdate.h> @@ -149,7 +148,7 @@ struct cgroup { struct css_set { /* Reference count */ - struct kref ref; + atomic_t refcount; /* * List running through all cgroup groups in the same hash |