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From: Al Viro <viro@zeniv.linux.org.uk>
To: Andrei Vagin <avagin@gmail.com>
Cc: David Howells <dhowells@redhat.com>,
	linux-fsdevel@vger.kernel.org, cgroups@vger.kernel.org,
	Li Zefan <lizefan@huawei.com>
Subject: Re: [PATCH vfs/for-next v6] cgroup: fix top cgroup refcnt leak
Date: Thu, 3 Jan 2019 08:32:29 +0000	[thread overview]
Message-ID: <20190103083229.GJ2217@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20190103035426.23526-1-avagin@gmail.com>

On Wed, Jan 02, 2019 at 07:54:26PM -0800, Andrei Vagin wrote:

[I'm thoroughly sick of refcounting in that thing, TBH ;-/]

> diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
> index a19f0fec9d82..fe67b5e81f9a 100644
> --- a/kernel/cgroup/cgroup.c
> +++ b/kernel/cgroup/cgroup.c
> @@ -2019,7 +2019,7 @@ int cgroup_do_get_tree(struct fs_context *fc)
>  
>  	ret = kernfs_get_tree(fc);
>  	if (ret < 0)
> -		goto out_cgrp;
> +		return ret;

Why does that case avoid needing cgroup_put()?  Note, BTW, that we
also have this:
/*
 * Destroy a cgroup filesystem context.
 */
static void cgroup_fs_context_free(struct fs_context *fc)
{
        struct cgroup_fs_context *ctx = cgroup_fc2context(fc);

        kfree(ctx->name);
        kfree(ctx->release_agent);
        if (ctx->root)
                cgroup_put(&ctx->root->cgrp);
        put_cgroup_ns(ctx->ns);
        kernfs_free_fs_context(fc);
        kfree(ctx);
}

which also needs to be taken into account.

  reply	other threads:[~2019-01-03  8:32 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-12-28 23:59 [PATCH] cgroup: fix top cgroup refcnt leak Andrei Vagin
2018-12-29  0:04 ` [PATCH vfs/for-next v2] " Andrei Vagin
2018-12-30 19:41   ` Andrei Vagin
2019-01-02  2:28   ` Al Viro
2019-01-02 18:14     ` [PATCH vfs/for-next v3] " Andrei Vagin
2019-01-02 19:37     ` [PATCH vfs/for-next v2] " Andrei Vagin
2019-01-02 19:37     ` [PATCH vfs/for-next v4] " Andrei Vagin
2019-01-02 20:02       ` Al Viro
2019-01-02 21:06         ` Andrei Vagin
2019-01-03  0:26         ` David Howells
2019-01-03  0:43           ` Andrei Vagin
2019-01-03  1:00             ` Andrei Vagin
2019-01-03  3:54               ` [PATCH vfs/for-next v6] " Andrei Vagin
2019-01-03  8:32                 ` Al Viro [this message]
2019-01-03 17:34                   ` Andrei Vagin
2019-01-03 21:54                   ` David Howells
2019-01-02 22:26 ` [PATCH vfs/for-next v2] " David Howells
2019-01-02 23:06   ` Andrei Vagin
2019-01-02 23:31     ` Andrei Vagin
2019-01-03  0:33     ` David Howells
2019-01-03 13:41     ` David Howells
2019-01-03 13:42     ` David Howells
2019-01-03 15:27     ` David Howells
2019-01-03 15:44     ` David Howells

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