6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Breno Leitao <leitao@xxxxxxxxxx> [ Upstream commit a57d5a72f8dec7db8a79d0016fb0a3bdecc82b56 ] The ndev->npinfo pointer in netpoll_poll_lock() is RCU-protected but is being accessed directly for a NULL check. While no RCU read lock is held in this context, we should still use proper RCU primitives for consistency and correctness. Replace the direct NULL check with rcu_access_pointer(), which is the appropriate primitive when only checking for NULL without dereferencing the pointer. This function provides the necessary ordering guarantees without requiring RCU read-side protection. Fixes: bea3348eef27 ("[NET]: Make NAPI polling independent of struct net_device objects.") Signed-off-by: Breno Leitao <leitao@xxxxxxxxxx> Reviewed-by: Michal Kubiak <michal.kubiak@xxxxxxxxx> Link: https://patch.msgid.link/20241118-netpoll_rcu-v1-2-a1888dcb4a02@xxxxxxxxxx Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- include/linux/netpoll.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/netpoll.h b/include/linux/netpoll.h index cd4e28db0cbd7..959a4daacea1f 100644 --- a/include/linux/netpoll.h +++ b/include/linux/netpoll.h @@ -72,7 +72,7 @@ static inline void *netpoll_poll_lock(struct napi_struct *napi) { struct net_device *dev = napi->dev; - if (dev && dev->npinfo) { + if (dev && rcu_access_pointer(dev->npinfo)) { int owner = smp_processor_id(); while (cmpxchg(&napi->poll_owner, -1, owner) != -1) -- 2.43.0