NothingOSS/android_kernel_msm-6.1_nothing_sm7635
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions
android_kernel_msm-6.1_noth.../kernel/cgroup
History
Tetsuo Handa 3756171b97 cgroup,freezer: hold cpu_hotplug_lock before freezer_mutex 
[ Upstream commit 57dcd64c7e036299ef526b400a8d12b8a2352f26 ]

syzbot is reporting circular locking dependency between cpu_hotplug_lock
and freezer_mutex, for commit f5d39b0208 ("freezer,sched: Rewrite core
freezer logic") replaced atomic_inc() in freezer_apply_state() with
static_branch_inc() which holds cpu_hotplug_lock.

cpu_hotplug_lock => cgroup_threadgroup_rwsem => freezer_mutex

  cgroup_file_write() {
    cgroup_procs_write() {
      __cgroup_procs_write() {
        cgroup_procs_write_start() {
          cgroup_attach_lock() {
            cpus_read_lock() {
              percpu_down_read(&cpu_hotplug_lock);
            }
            percpu_down_write(&cgroup_threadgroup_rwsem);
          }
        }
        cgroup_attach_task() {
          cgroup_migrate() {
            cgroup_migrate_execute() {
              freezer_attach() {
                mutex_lock(&freezer_mutex);
                (...snipped...)
              }
            }
          }
        }
        (...snipped...)
      }
    }
  }

freezer_mutex => cpu_hotplug_lock

  cgroup_file_write() {
    freezer_write() {
      freezer_change_state() {
        mutex_lock(&freezer_mutex);
        freezer_apply_state() {
          static_branch_inc(&freezer_active) {
            static_key_slow_inc() {
              cpus_read_lock();
              static_key_slow_inc_cpuslocked();
              cpus_read_unlock();
            }
          }
        }
        mutex_unlock(&freezer_mutex);
      }
    }
  }

Swap locking order by moving cpus_read_lock() in freezer_apply_state()
to before mutex_lock(&freezer_mutex) in freezer_change_state().

Reported-by: syzbot <syzbot+c39682e86c9d84152f93@syzkaller.appspotmail.com>
Link: https://syzkaller.appspot.com/bug?extid=c39682e86c9d84152f93
Suggested-by: Hillf Danton <hdanton@sina.com>
Fixes: f5d39b0208 ("freezer,sched: Rewrite core freezer logic")
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Mukesh Ojha <quic_mojha@quicinc.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-04-20 12:35:09 +02:00
..
cgroup-internal.h memcg: Fix possible use-after-free in memcg_write_event_control() 2022-12-08 10:40:58 -08:00
cgroup-v1.c cgroup: Use cgroup_attach_{lock,unlock}() from cgroup_attach_task_all() 2022-08-26 11:14:34 -10:00
cgroup.c cgroup fixes for v6.1-rc1 2022-10-17 18:52:43 -07:00
cpuset.c cpuset: Call set_cpus_allowed_ptr() with appropriate mask for task 2023-02-14 19:11:45 +01:00
debug.c kernel: cgroup: fix misuse of %x 2019-05-06 08:47:48 -07:00
freezer.c cgroup: cleanup comments 2022-03-13 19:19:27 -10:00
legacy_freezer.c cgroup,freezer: hold cpu_hotplug_lock before freezer_mutex 2023-04-20 12:35:09 +02:00
Makefile cgroup: Add misc cgroup controller 2021-04-04 13:34:46 -04:00
misc.c misc_cgroup: remove error log to avoid log flood 2021-09-20 07:35:38 -10:00
namespace.c memcg: enable accounting for new namesapces and struct nsproxy 2021-09-03 09:58:12 -07:00
pids.c cgroup: add pids.peak interface for pids controller 2022-09-04 09:26:51 -10:00
rdma.c cgroup: fix spelling mistakes 2021-05-24 12:45:26 -04:00
rstat.c cgroup: bpf: enable bpf programs to integrate with rstat 2022-08-25 11:35:37 -07:00