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From: Tejun Heo <tj@kernel.org>
To: serge.hallyn@ubuntu.com
Cc: linux-kernel@vger.kernel.org, adityakali@google.com,
	linux-api@vger.kernel.org, containers@lists.linux-foundation.org,
	cgroups@vger.kernel.org, akpm@linux-foundation.org,
	ebiederm@xmission.com, gregkh@linuxfoundation.org,
	lizefan@huawei.com, hannes@cmpxchg.org
Subject: Re: [PATCH 2/2] mountinfo: implement show_path for kernfs and cgroup
Date: Mon, 2 May 2016 12:34:41 -0400	[thread overview]
Message-ID: <20160502163441.GV7822@mtj.duckdns.org> (raw)
In-Reply-To: <1460923472-29370-3-git-send-email-serge.hallyn@ubuntu.com>

Hello,

On Sun, Apr 17, 2016 at 03:04:32PM -0500, serge.hallyn@ubuntu.com wrote:
> +static int cgroup_show_path(struct seq_file *sf, struct kernfs_node *kf_node,
> +			    struct kernfs_root *kf_root)
> +{
> +	int len = 0, ret = 0;
> +	char *buf = NULL;
> +	struct cgroup_namespace *ns = current->nsproxy->cgroup_ns;
> +	struct cgroup_root *kf_cgroot = cgroup_root_from_kf(kf_root);
> +	struct cgroup *ns_cgroup;
> +
> +	mutex_lock(&cgroup_mutex);
> +	spin_lock_bh(&css_set_lock);
> +	ns_cgroup = cset_cgroup_from_root(ns->root_cset, kf_cgroot);
> +	len = kernfs_path_from_node(kf_node, ns_cgroup->kn, NULL, 0);
> +	if (len > 0)
> +		buf = kmalloc(len + 1, GFP_ATOMIC);

Ugh... What's up with GFP_ATOMIC?  Just allocate maximum sized buffer
before grabbing any locks.

Thanks.

-- 
tejun

      parent reply	other threads:[~2016-05-02 16:34 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-04-17 20:04 Show virtualized dentry root in mountinfo for cgroupfs serge.hallyn
2016-04-17 20:04 ` [PATCH 1/2] kernfs_path_from_node_locked: don't overwrite nlen serge.hallyn
2016-04-20 19:43   ` Tejun Heo
2016-05-02 16:32     ` Tejun Heo
2016-05-02 16:41       ` Greg KH
2016-04-17 20:04 ` [PATCH 2/2] mountinfo: implement show_path for kernfs and cgroup serge.hallyn
2016-04-18  4:11   ` Serge E. Hallyn
2016-04-18  5:29     ` [PATCH 3/2] cgroup_show_path: use a new helper to get current cgns css_set Serge E. Hallyn
2016-04-29 21:42       ` Serge E. Hallyn
2016-05-02 16:35         ` Tejun Heo
2016-05-03 14:26           ` Serge E. Hallyn
2016-04-19  1:12     ` [PATCH 2/2] mountinfo: implement show_path for kernfs and cgroup Eric W. Biederman
2016-04-19  1:44       ` Serge E. Hallyn
2016-04-19  4:05         ` Serge E. Hallyn
2016-04-26  2:42           ` Serge E. Hallyn
2016-04-26 10:29             ` Karel Zak
2016-04-26 14:36               ` Serge E. Hallyn
2016-05-02 16:33                 ` Tejun Heo
2016-05-02 16:34   ` Tejun Heo [this message]

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