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.]
[[email protected]: repair comments]
[[email protected]: eliminate race in css_set refcounting]
Signed-off-by: Lai Jiangshan <[email protected]>
Cc: Balbir Singh <[email protected]>
Cc: KAMEZAWA Hiroyuki <[email protected]>
Signed-off-by: Paul Menage <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
The "releasable" control file provided by the cgroup framework exports the
state of a per-cgroup flag that's related to the notify-on-release feature.
This isn't really generally useful, unless you're trying to debug this
particular feature of cgroups.
This patch moves the "releasable" file to the cgroup_debug subsystem.
Signed-off-by: Paul Menage <[email protected]>
Cc: "Li Zefan" <[email protected]>
Cc: Balbir Singh <[email protected]>
Cc: Paul Jackson <[email protected]>
Cc: Pavel Emelyanov <[email protected]>
Cc: KAMEZAWA Hiroyuki <[email protected]>
Cc: "YAMAMOTO Takashi" <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Lai Jiangshan