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From:   David Howells <dhowells@redhat.com>
In-Reply-To: <1590415886-52353-1-git-send-email-xiyuyang19@fudan.edu.cn>
References: <1590415886-52353-1-git-send-email-xiyuyang19@fudan.edu.cn>
To:     Xiyu Yang <xiyuyang19@fudan.edu.cn>
Cc:     dhowells@redhat.com, linux-afs@lists.infradead.org,
        linux-kernel@vger.kernel.org, yuanxzhang@fudan.edu.cn,
        kjlu@umn.edu, Xin Tan <tanxin.ctf@gmail.com>
Subject: Re: [PATCH] afs: Fix afs_cb_interest refcnt leak in afs_select_fileserver()
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Date:   Tue, 26 May 2020 17:18:59 +0100
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Xiyu Yang <xiyuyang19@fudan.edu.cn> wrote:

>  	error = afs_wait_for_fs_probes(fc->server_list, fc->untried);
> -	if (error < 0)
> +	if (error < 0) {
> +		afs_put_cb_interest(afs_v2net(vnode), fc->cbi);
>  		goto failed_set_error;
> +	}

Ummm...  Did you try this?  afs_end_vnode_operation() should then cause a
double free because you don't clear fc->cbi.

You can try it by installing the kafs-client package if your distribution has
it available and starting the afs.mount service or doing:

	mount -t afs none /afs -o dyn

and then:

	ls /afs/grand.central.org/

David