linux-kernel - Re: [PATCH 1/4] target: Obtain se_node_acl->acl_kref during get_initiator_node

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Fri, 8 Jan 2016 09:14:12 +0100
From:	Christoph Hellwig <hch@....de>
To:	"Nicholas A. Bellinger" <nab@...erainc.com>
Cc:	target-devel <target-devel@...r.kernel.org>,
	linux-scsi <linux-scsi@...r.kernel.org>,
	lkml <linux-kernel@...r.kernel.org>,
	Sagi Grimberg <sagig@...lanox.com>,
	Christoph Hellwig <hch@....de>, Hannes Reinecke <hare@...e.de>,
	Andy Grover <agrover@...hat.com>,
	Vasu Dev <vasu.dev@...ux.intel.com>, Vu Pham <vu@...lanox.com>,
	Nicholas Bellinger <nab@...ux-iscsi.org>
Subject: Re: [PATCH 1/4] target: Obtain se_node_acl->acl_kref during
	get_initiator_node_acl

>  	mutex_lock(&tpg->acl_node_mutex);
>  	acl = __core_tpg_get_initiator_node_acl(tpg, initiatorname);
> +	/*
> +	 * Obtain the acl_kref now, which will be dropped upon the
> +	 * release of se_sess memory within transport_free_session().
> +	 */
> +	if (acl)
> +		kref_get(&acl->acl_kref);

І think the comment is highly confusing as it's about one of the
callers, while the function has many.

I'd suggest you move it to core_tpg_check_initiator_node_acl instead.

Also I think iscsit_build_sendtargets_response will need a put on
the nacl, otherwise you'll leak references.

While we're at it - is there any god reason to keep acl_pr_ref_count
as a separate entity from acl_kref?

>  void transport_free_session(struct se_session *se_sess)
>  {
> +	struct se_node_acl *se_nacl = se_sess->se_node_acl;
> +	/*
> +	 * Drop the se_node_acl->nacl_kref obtained from within
> +	 * core_tpg_get_initiator_node_acl().
> +	 */
> +	if (se_nacl) {
> +		se_sess->se_node_acl = NULL;

Whats the point of zeroing se_node_acl just before freeing se_sess?

>  	/*
>  	 * If last kref is dropping now for an explicit NodeACL, awake sleeping
>  	 * ->acl_free_comp caller to wakeup configfs se_node_acl->acl_group
> -	 * removal context.
> +	 * removal context from within transport_free_session() code.
>  	 */

The comment neds to move to transport_free_session.  Or maybe just removed
given that it's obvious from the code flow.