diff options
| author | Tetsuo Handa | 2023-06-11 22:48:12 +0900 |
|---|---|---|
| committer | Greg Kroah-Hartman | 2023-06-28 11:12:25 +0200 |
| commit | 0d7a4e6589a02fd87d286f7f0713ba6d8fc344e6 (patch) | |
| tree | 63387fbba00dd38cf7b745070d895d3f464a4b27 /kernel/cgroup | |
| parent | 7b162a18d332bd5ca7ff9170ded674b4cdad31f7 (diff) | |
cgroup,freezer: hold cpu_hotplug_lock before freezer_mutex in freezer_css_{online,offline}()
commit f0cc749254d12c78e93dae3b27b21dc9546843d0 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel/cgroup')
| -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) |