diff options
| author | Breno Leitao <leitao@debian.org> | 2025-03-06 05:16:18 -0800 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2025-03-07 19:57:33 -0800 |
| commit | 505ead7ab77f289f12d8a68ac83da068e4d4408b (patch) | |
| tree | 2adfcc0791444ce67dbd7288931a83e17ed8c960 /net/core | |
| parent | e6360f0dc52b93a723c748e281fb99b430297da4 (diff) | |
netpoll: hold rcu read lock in __netpoll_send_skb()
The function __netpoll_send_skb() is being invoked without holding the
RCU read lock. This oversight triggers a warning message when
CONFIG_PROVE_RCU_LIST is enabled:
net/core/netpoll.c:330 suspicious rcu_dereference_check() usage!
netpoll_send_skb
netpoll_send_udp
write_ext_msg
console_flush_all
console_unlock
vprintk_emit
To prevent npinfo from disappearing unexpectedly, ensure that
__netpoll_send_skb() is protected with the RCU read lock.
Fixes: 2899656b494dcd1 ("netpoll: take rcu_read_lock_bh() in netpoll_send_skb_on_dev()")
Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20250306-netpoll_rcu_v2-v2-1-bc4f5c51742a@debian.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/core')
| -rw-r--r-- | net/core/netpoll.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/net/core/netpoll.c b/net/core/netpoll.c index 62b4041aae1a..0ab722d95a2d 100644 --- a/net/core/netpoll.c +++ b/net/core/netpoll.c @@ -319,6 +319,7 @@ static int netpoll_owner_active(struct net_device *dev) static netdev_tx_t __netpoll_send_skb(struct netpoll *np, struct sk_buff *skb) { netdev_tx_t status = NETDEV_TX_BUSY; + netdev_tx_t ret = NET_XMIT_DROP; struct net_device *dev; unsigned long tries; /* It is up to the caller to keep npinfo alive. */ @@ -327,11 +328,12 @@ static netdev_tx_t __netpoll_send_skb(struct netpoll *np, struct sk_buff *skb) lockdep_assert_irqs_disabled(); dev = np->dev; + rcu_read_lock(); npinfo = rcu_dereference_bh(dev->npinfo); if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) { dev_kfree_skb_irq(skb); - return NET_XMIT_DROP; + goto out; } /* don't get messages out of order, and no recursion */ @@ -370,7 +372,10 @@ static netdev_tx_t __netpoll_send_skb(struct netpoll *np, struct sk_buff *skb) skb_queue_tail(&npinfo->txq, skb); schedule_delayed_work(&npinfo->tx_work,0); } - return NETDEV_TX_OK; + ret = NETDEV_TX_OK; +out: + rcu_read_unlock(); + return ret; } netdev_tx_t netpoll_send_skb(struct netpoll *np, struct sk_buff *skb) |