diff options
Diffstat (limited to 'kernel/cgroup')
| -rw-r--r-- | kernel/cgroup/cgroup.c | 23 |
1 files changed, 22 insertions, 1 deletions
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 38f8d9df8fbc..b5b461d4418b 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -3996,6 +3996,7 @@ static ssize_t pressure_write(struct kernfs_open_file *of, char *buf, struct psi_trigger *new; struct cgroup *cgrp; struct psi_group *psi; + bool need_rtpoll_worker; ssize_t ret = 0; cgrp = cgroup_kn_lock_live(of->kn, false); @@ -4015,12 +4016,32 @@ static ssize_t pressure_write(struct kernfs_open_file *of, char *buf, } psi = cgroup_psi(cgrp); - new = psi_trigger_create(psi, buf, res, of->file, of); + new = psi_trigger_create(psi, buf, res, of->file, of, + &need_rtpoll_worker); if (IS_ERR(new)) { ret = PTR_ERR(new); goto out_unlock; } + /* + * The worker fork must run with neither cgroup_mutex nor the file's + * kernfs active reference held. The latter is broken since + * cgroup_kn_lock_live(). @of->priv may be released while unlocked, so + * recheck before publishing @new. + */ + if (need_rtpoll_worker) { + cgroup_unlock(); + ret = psi_trigger_create_rtpoll_worker(psi); + cgroup_lock(); + + if (!ret && !of->priv) + ret = -ENODEV; + if (ret) { + psi_trigger_destroy(new); + goto out_unlock; + } + } + smp_store_release(&ctx->psi.trigger, new); out_unlock: |