diff options
| author | Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> | 2023-06-11 22:48:12 +0900 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2023-06-12 06:39:48 -1000 |
| commit | f0cc749254d12c78e93dae3b27b21dc9546843d0 (patch) | |
| tree | 2be9cf39c3d4388880a43bbe03cddc31db9d2f13 /kernel | |
| parent | 5647e53f7856bb39dae781fe26aa65a699e2fc9f (diff) | |
cgroup,freezer: hold cpu_hotplug_lock before freezer_mutex in freezer_css_{online,offline}()
syzbot is again reporting circular locking dependency between
cpu_hotplug_lock and freezer_mutex. Do like what we did with
commit 57dcd64c7e036299 ("cgroup,freezer: hold cpu_hotplug_lock
before freezer_mutex").
Reported-by: syzbot <syzbot+2ab700fe1829880a2ec6@syzkaller.appspotmail.com>
Closes: https://syzkaller.appspot.com/bug?extid=2ab700fe1829880a2ec6
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Tested-by: syzbot <syzbot+2ab700fe1829880a2ec6@syzkaller.appspotmail.com>
Fixes: f5d39b020809 ("freezer,sched: Rewrite core freezer logic")
Cc: stable@vger.kernel.org # v6.1+
Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/cgroup/legacy_freezer.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/kernel/cgroup/legacy_freezer.c b/kernel/cgroup/legacy_freezer.c index 936473203a6b..122dacb3a443 100644 --- a/kernel/cgroup/legacy_freezer.c +++ b/kernel/cgroup/legacy_freezer.c @@ -108,16 +108,18 @@ static int freezer_css_online(struct cgroup_subsys_state *css) struct freezer *freezer = css_freezer(css); struct freezer *parent = parent_freezer(freezer); + cpus_read_lock(); mutex_lock(&freezer_mutex); freezer->state |= CGROUP_FREEZER_ONLINE; if (parent && (parent->state & CGROUP_FREEZING)) { freezer->state |= CGROUP_FREEZING_PARENT | CGROUP_FROZEN; - static_branch_inc(&freezer_active); + static_branch_inc_cpuslocked(&freezer_active); } mutex_unlock(&freezer_mutex); + cpus_read_unlock(); return 0; } @@ -132,14 +134,16 @@ static void freezer_css_offline(struct cgroup_subsys_state *css) { struct freezer *freezer = css_freezer(css); + cpus_read_lock(); mutex_lock(&freezer_mutex); if (freezer->state & CGROUP_FREEZING) - static_branch_dec(&freezer_active); + static_branch_dec_cpuslocked(&freezer_active); freezer->state = 0; mutex_unlock(&freezer_mutex); + cpus_read_unlock(); } static void freezer_css_free(struct cgroup_subsys_state *css) |