net: netpoll: initialize work queue before error checks

Prevent a kernel warning when netconsole setup fails on devices with
IFF_DISABLE_NETPOLL flag. The warning (at kernel/workqueue.c:4242 in
__flush_work) occurs because the cleanup path tries to cancel an
uninitialized work queue.

When __netpoll_setup() encounters a device with IFF_DISABLE_NETPOLL,
it fails early and calls skb_pool_flush() for cleanup. This function
calls cancel_work_sync(&np->refill_wq), but refill_wq hasn't been
initialized yet, triggering the warning.

Move INIT_WORK() to the beginning of __netpoll_setup(), ensuring the
work queue is properly initialized before any potential failure points.
This allows the cleanup path to safely cancel the work queue regardless
of where the setup fails.

Fixes: 248f6571fd4c5 ("netpoll: Optimize skb refilling on critical path")
Signed-off-by: Breno Leitao <leitao@debian.org>
Link: https://patch.msgid.link/20251127-netpoll_fix_init_work-v1-1-65c07806d736@debian.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index 331764845e8fa573aaca70ae080c7abcbe5bd53b..09f72f10813cc67ad22357c86bdd67f6c7903464 100644 (file)
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -554,6 +554,7 @@ int __netpoll_setup(struct netpoll *np, struct net_device *ndev)
        int err;
 
        skb_queue_head_init(&np->skb_pool);
+       INIT_WORK(&np->refill_wq, refill_skbs_work_handler);
 
        if (ndev->priv_flags & IFF_DISABLE_NETPOLL) {
                np_err(np, "%s doesn't support polling, aborting\n",
@@ -591,7 +592,6 @@ int __netpoll_setup(struct netpoll *np, struct net_device *ndev)
 
        /* fill up the skb queue */
        refill_skbs(np);
-       INIT_WORK(&np->refill_wq, refill_skbs_work_handler);
 
        /* last thing to do is link it to the net device structure */
        rcu_assign_pointer(ndev->npinfo, npinfo);