| Message ID | 20110829140418.GB18871@mtj.dyndns.org (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
On 08/29, Tejun Heo wrote: > > --- work.orig/kernel/cgroup_freezer.c > +++ work/kernel/cgroup_freezer.c > @@ -311,14 +311,14 @@ static int freezer_change_state(struct c > if (goal_state == freezer->state) > goto out; > > - freezer->state = goal_state; > - > switch (goal_state) { > case CGROUP_THAWED: > + freezer->state = CGROUP_THAWED; > atomic_dec(&system_freezing_cnt); > unfreeze_cgroup(cgroup, freezer); > break; > case CGROUP_FROZEN: > + freezer->state = CGROUP_FREEZING; At first glance, this is correct. I'll try to recheck. But, > atomic_inc(&system_freezing_cnt); iiuc this becomes wrong... Suppose a user writes "FROZEN" twice, before freezer->state becomes CGROUP_FROZEN. I think we should actually fix the "goal_state == freezer->state" check above. Oleg.
Index: work/kernel/cgroup_freezer.c =================================================================== --- work.orig/kernel/cgroup_freezer.c +++ work/kernel/cgroup_freezer.c @@ -311,14 +311,14 @@ static int freezer_change_state(struct c if (goal_state == freezer->state) goto out; - freezer->state = goal_state; - switch (goal_state) { case CGROUP_THAWED: + freezer->state = CGROUP_THAWED; atomic_dec(&system_freezing_cnt); unfreeze_cgroup(cgroup, freezer); break; case CGROUP_FROZEN: + freezer->state = CGROUP_FREEZING; atomic_inc(&system_freezing_cnt); retval = try_to_freeze_cgroup(cgroup, freezer); break;
d02f52811d0e "cgroup_freezer: prepare for removal of TIF_FREEZE" moved setting of freezer->state into freezer_change_state(); unfortunately, while doing so, when it's beginning to freeze tasks, it sets the state to CGROUP_FROZEN instead of CGROUP_FREEZING ending up skipping the whole freezing state. Fix it. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Oleg Nesterov <oleg@redhat.com> Cc: Paul Menage <paul@paulmenage.org> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> --- Rafael, these four patches fix the issues spotted by Oleg during review of the freezer patchset. Please apply them on pm-freezer once Oleg acks them. Thanks. kernel/cgroup_freezer.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)