Commit 095f0f1b authored Dec 31, 2021 by Xunlei Pang Committed by Zheng Zengkai Dec 31, 2021

cgroup: Fix task_css_check rcu warnings

hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I4OF4N



------------------------------------------

task_css() should be protected by rcu. In my environment
if not protected by rcu qemu may fail to start.

Fixes: a885e3f9 ("psi: support psi under cgroup v1")
Reported-by: Yang Yingliang <yangyingliang@huawei.com>
Acked-by: Michael Wang <yun.wany@linux.alibaba.com>
Signed-off-by: Xunlei Pang <xlpang@linux.alibaba.com>
Signed-off-by: Yihao Wu <wuyihao@linux.alibaba.com>
Acked-by: Yang Shi <yang.shi@linux.alibaba.com>
Signed-off-by: Chen Wandun <chenwandun@huawei.com>
Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>

parent efd726a9

kernel/sched/psi.c

+4 −1

Original line number	Diff line number	Diff line
		@@ -755,12 +755,15 @@ static struct psi_group iterate_groups(struct task_struct task, void **iter)
		if (!*iter) {
		if (static_branch_likely(&psi_v1_disabled))
		cgroup = task->cgroups->dfl_cgrp;
		else
		else {
		#ifdef CONFIG_CGROUP_CPUACCT
		rcu_read_lock();
		cgroup = task_cgroup(task, cpuacct_cgrp_id);
		rcu_read_unlock();
		#else
		cgroup = NULL;
		#endif
		}
		} else if (*iter == &psi_system)
		return NULL;
		else