linux-kernel - [PATCH 4.0 002/148] fs_pin: Allow for the possibility that m_list or s

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:	Wed,  3 Jun 2015 21:07:52 +0900
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	stable@...r.kernel.org, "Eric W. Biederman" <ebiederm@...ssion.com>
Subject: [PATCH 4.0 002/148] fs_pin: Allow for the possibility that m_list or s_list go unused.

4.0-stable review patch.  If anyone has any objections, please let me know.

------------------

From: "Eric W. Biederman" <ebiederm@...ssion.com>

commit 820f9f147dcce2602eefd9b575bbbd9ea14f0953 upstream.

This is needed to support lazily umounting locked mounts.  Because the
entire unmounted subtree needs to stay together until there are no
users with references to any part of the subtree.

To support this guarantee that the fs_pin m_list and s_list nodes
are initialized by initializing them in init_fs_pin allowing
for the possibility that pin_insert_group does not touch them.

Further use hlist_del_init in pin_remove so that there is
a hlist_unhashed test before the list we attempt to update
the previous list item.

Signed-off-by: "Eric W. Biederman" <ebiederm@...ssion.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 fs/fs_pin.c            |    4 ++--
 include/linux/fs_pin.h |    2 ++
 2 files changed, 4 insertions(+), 2 deletions(-)

--- a/fs/fs_pin.c
+++ b/fs/fs_pin.c
@@ -9,8 +9,8 @@ static DEFINE_SPINLOCK(pin_lock);
 void pin_remove(struct fs_pin *pin)
 {
 	spin_lock(&pin_lock);
-	hlist_del(&pin->m_list);
-	hlist_del(&pin->s_list);
+	hlist_del_init(&pin->m_list);
+	hlist_del_init(&pin->s_list);
 	spin_unlock(&pin_lock);
 	spin_lock_irq(&pin->wait.lock);
 	pin->done = 1;
--- a/include/linux/fs_pin.h
+++ b/include/linux/fs_pin.h
@@ -13,6 +13,8 @@ struct vfsmount;
 static inline void init_fs_pin(struct fs_pin *p, void (*kill)(struct fs_pin *))
 {
 	init_waitqueue_head(&p->wait);
+	INIT_HLIST_NODE(&p->s_list);
+	INIT_HLIST_NODE(&p->m_list);
 	p->kill = kill;
 }

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/