Unverified Commit 53b2031b authored by openeuler-ci-bot's avatar openeuler-ci-bot Committed by Gitee
Browse files

!6283 fix deadlock in cgroup1_writeback V2 

Merge Pull Request from: @ci-robot 
 
PR sync from: Chen Ridong <chenridong@huawei.com>
https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/SQHFK3SWCKXVAJXS3MX2DS2OTQUMAMOW/ 
*** BLURB HERE ***

Chen Ridong (2):
  cgroup_writeback: Revert "fix deadlock in cgroup1_writeback"
  cgroup_writeback: fix deadlock in cgroup1_writeback


-- 
2.34.1
 
https://gitee.com/openeuler/kernel/issues/I99KM6 
 
Link:https://gitee.com/openeuler/kernel/pulls/6283

 

Reviewed-by: default avatarZhang Peng <zhangpeng362@huawei.com>
Signed-off-by: default avatarZhang Peng <zhangpeng362@huawei.com>
parents 0a8d8bc5 d6826843

mm/backing-dev.c

+5 −2
Original line number Diff line number Diff line
@@ -578,8 +578,8 @@ static struct cgroup_subsys_state *cgwbv1_get_blkcss(struct mem_cgroup *memcg) 
	struct cgroup_subsys_state *blkcg_css;



	rcu_read_lock();

	blkcg_css = memcg->wb_blk_css;

	if (!css_tryget_online(blkcg_css)) {

	blkcg_css = READ_ONCE(memcg->wb_blk_css);

	if (!blkcg_css || !css_tryget_online(blkcg_css)) {

		blkcg_css = blkcg_root_css;

		css_get(blkcg_css);

	}
@@ -1180,6 +1180,7 @@ static void wb_kill_memcg(struct cgroup_subsys_state *memcg_css) 


	list_del_init(&memcg->memcg_node);

	css_put(memcg->wb_blk_css);

	memcg->wb_blk_css = NULL;

}



static void wb_kill_blkcg(struct cgroup_subsys_state *blkcg_css)
@@ -1221,6 +1222,8 @@ void wb_attach_memcg_to_blkcg(struct cgroup_subsys_state *memcg_css, 
	if (!cgroup1_writeback)

		return;



	lockdep_assert_held(&cgroup_mutex);



	css_get(blkcg_css);

	memcg->wb_blk_css = blkcg_css;

	if (pre_blkcss == NULL)

mm/memcontrol.c

+10 −14
Original line number Diff line number Diff line
@@ -6041,6 +6041,7 @@ static ssize_t memcg_high_async_ratio_write(struct kernfs_open_file *of, 


static int wb_blkio_show(struct seq_file *m, void *v)

{

	struct kernfs_open_file *of = m->private;

	char *path;

	ino_t blkcg_id;

	struct cgroup *blkcg_cgroup;
@@ -6054,22 +6055,18 @@ static int wb_blkio_show(struct seq_file *m, void *v) 
	if (!path)

		return -ENOMEM;



	rcu_read_lock();

	blkcg_css = memcg->wb_blk_css;

	if (!css_tryget_online(blkcg_css)) {

	if (!cgroup_kn_lock_live(of->kn, false)) {

		kfree(path);

		rcu_read_unlock();



		return -EINVAL;

		return -ENODEV;

	}

	blkcg_css = memcg->wb_blk_css;

	blkcg_cgroup = blkcg_css->cgroup;

	blkcg_id = cgroup_ino(blkcg_cgroup);

	cgroup_path(blkcg_cgroup, path, PATH_MAX);

	cgroup_kn_unlock(of->kn);

	seq_printf(m, "wb_blkio_path:%s\n", path);

	seq_printf(m, "wb_blkio_ino:%lu\n", blkcg_id);

	kfree(path);

	css_put(blkcg_css);

	rcu_read_unlock();



	return 0;

}
@@ -6092,24 +6089,23 @@ static ssize_t wb_blkio_write(struct kernfs_open_file *of, char *buf, 
	if (ret)

		return ret;



	rcu_read_lock();

	if (!cgroup_kn_lock_live(of->kn, false))

		return -ENODEV;

	root = blkcg_root_css->cgroup->root;

	blk_cgroup = __cgroup_get_from_id(root, cgrp_id);

	if (IS_ERR(blk_cgroup)) {

		rcu_read_unlock();

		cgroup_kn_unlock(of->kn);

		return -EINVAL;

	}

	blkcg_css = cgroup_tryget_css(blk_cgroup, &io_cgrp_subsys);

	if (!blkcg_css) {

		ret = -EINVAL;

	if (!blkcg_css)

		goto out_unlock;

	}

	wb_attach_memcg_to_blkcg(memcg_css, blkcg_css);

	css_put(blkcg_css);



out_unlock:

	cgroup_put(blk_cgroup);

	rcu_read_unlock();

	cgroup_kn_unlock(of->kn);



	return ret < 0 ? ret : nbytes;

}