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can: j1939: change j1939_netdev_lock type to mutex

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It turns out access to j1939_can_rx_register() needs to be serialized,
otherwise j1939_priv can be corrupted when parallel threads call
j1939_netdev_start() and j1939_can_rx_register() fails. This issue is
thoroughly covered in other commit which serializes access to
j1939_can_rx_register().

Change j1939_netdev_lock type to mutex so that we do not need to remove
GFP_KERNEL from can_rx_register().

j1939_netdev_lock seems to be used in normal contexts where mutex usage
is not prohibited.

Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

Fixes: 9d71dd0c70 ("can: add support of SAE J1939 protocol")
Suggested-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
Tested-by: Oleksij Rempel <o.rempel@pengutronix.de>
Acked-by: Oleksij Rempel <o.rempel@pengutronix.de>
Link: https://lore.kernel.org/r/20230526171910.227615-2-pchelkin@ispras.ru
Cc: stable@vger.kernel.org
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
This commit is contained in:
Fedor Pchelkin 2023-05-26 20:19:09 +03:00 committed by Marc Kleine-Budde
parent 2a84aea80e
commit cd9c790de2
1 changed files with 11 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
net/can/j1939/main.c
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@ -126,7 +126,7 @@ static void j1939_can_recv(struct sk_buff *iskb, void *data)
#define J1939_CAN_ID CAN_EFF_FLAG
#define J1939_CAN_MASK (CAN_EFF_FLAG | CAN_RTR_FLAG)
static DEFINE_SPINLOCK(j1939_netdev_lock);
static DEFINE_MUTEX(j1939_netdev_lock);
static struct j1939_priv *j1939_priv_create(struct net_device *ndev)
{
@ -220,7 +220,7 @@ static void __j1939_rx_release(struct kref *kref)
j1939_can_rx_unregister(priv);
j1939_ecu_unmap_all(priv);
j1939_priv_set(priv->ndev, NULL);
spin_unlock(&j1939_netdev_lock);
mutex_unlock(&j1939_netdev_lock);
}
/* get pointer to priv without increasing ref counter */
@ -248,9 +248,9 @@ static struct j1939_priv *j1939_priv_get_by_ndev(struct net_device *ndev)
{
struct j1939_priv *priv;
spin_lock(&j1939_netdev_lock);
mutex_lock(&j1939_netdev_lock);
priv = j1939_priv_get_by_ndev_locked(ndev);
spin_unlock(&j1939_netdev_lock);
mutex_unlock(&j1939_netdev_lock);
return priv;
}
@ -260,14 +260,14 @@ struct j1939_priv *j1939_netdev_start(struct net_device *ndev)
struct j1939_priv *priv, *priv_new;
int ret;
spin_lock(&j1939_netdev_lock);
mutex_lock(&j1939_netdev_lock);
priv = j1939_priv_get_by_ndev_locked(ndev);
if (priv) {
kref_get(&priv->rx_kref);
spin_unlock(&j1939_netdev_lock);
mutex_unlock(&j1939_netdev_lock);
return priv;
}
spin_unlock(&j1939_netdev_lock);
mutex_unlock(&j1939_netdev_lock);
priv = j1939_priv_create(ndev);
if (!priv)
@ -277,20 +277,20 @@ struct j1939_priv *j1939_netdev_start(struct net_device *ndev)
spin_lock_init(&priv->j1939_socks_lock);
INIT_LIST_HEAD(&priv->j1939_socks);
spin_lock(&j1939_netdev_lock);
mutex_lock(&j1939_netdev_lock);
priv_new = j1939_priv_get_by_ndev_locked(ndev);
if (priv_new) {
/* Someone was faster than us, use their priv and roll
* back our's.
*/
kref_get(&priv_new->rx_kref);
spin_unlock(&j1939_netdev_lock);
mutex_unlock(&j1939_netdev_lock);
dev_put(ndev);
kfree(priv);
return priv_new;
}
j1939_priv_set(ndev, priv);
spin_unlock(&j1939_netdev_lock);
mutex_unlock(&j1939_netdev_lock);
ret = j1939_can_rx_register(priv);
if (ret < 0)
@ -308,7 +308,7 @@ struct j1939_priv *j1939_netdev_start(struct net_device *ndev)
void j1939_netdev_stop(struct j1939_priv *priv)
{
kref_put_lock(&priv->rx_kref, __j1939_rx_release, &j1939_netdev_lock);
kref_put_mutex(&priv->rx_kref, __j1939_rx_release, &j1939_netdev_lock);
j1939_priv_put(priv);
}