From: Wei Fang wei.fang@nxp.com

[ Upstream commit c2e0c58b25a0a0c37ec643255558c5af4450c9f5 ]

There is a deadlock issue found in sungem driver, please refer to the commit ac0a230f719b ("eth: sungem: remove .ndo_poll_controller to avoid deadlocks"). The root cause of the issue is that netpoll is in atomic context and disable_irq() is called by .ndo_poll_controller interface of sungem driver, however, disable_irq() might sleep. After analyzing the implementation of fec_poll_controller(), the fec driver should have the same issue. Due to the fec driver uses NAPI for TX completions, the .ndo_poll_controller is unnecessary to be implemented in the fec driver, so fec_poll_controller() can be safely removed.

Fixes: 7f5c6addcdc0 ("net/fec: add poll controller function for fec nic") Signed-off-by: Wei Fang wei.fang@nxp.com Link: https://lore.kernel.org/r/20240511062009.652918-1-wei.fang@nxp.com Signed-off-by: Jakub Kicinski kuba@kernel.org [Minor context change fixed] Signed-off-by: Feng Liu Feng.Liu3@windriver.com Signed-off-by: He Zhe Zhe.He@windriver.com --- Verified the build test. --- drivers/net/ethernet/freescale/fec_main.c | 26 ----------------------- 1 file changed, 26 deletions(-)

diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c index 7b5585bc21d8..7a74a765784a 100644 --- a/drivers/net/ethernet/freescale/fec_main.c +++ b/drivers/net/ethernet/freescale/fec_main.c @@ -3432,29 +3432,6 @@ fec_set_mac_address(struct net_device *ndev, void *p) return 0; }

-#ifdef CONFIG_NET_POLL_CONTROLLER -/** - * fec_poll_controller - FEC Poll controller function - * @dev: The FEC network adapter - * - * Polled functionality used by netconsole and others in non interrupt mode - * - */ -static void fec_poll_controller(struct net_device *dev) -{ - int i; - struct fec_enet_private *fep = netdev_priv(dev); - - for (i = 0; i < FEC_IRQ_NUM; i++) { - if (fep->irq[i] > 0) { - disable_irq(fep->irq[i]); - fec_enet_interrupt(fep->irq[i], dev); - enable_irq(fep->irq[i]); - } - } -} -#endif - static inline void fec_enet_set_netdev_features(struct net_device *netdev, netdev_features_t features) { @@ -3528,9 +3505,6 @@ static const struct net_device_ops fec_netdev_ops = { .ndo_tx_timeout = fec_timeout, .ndo_set_mac_address = fec_set_mac_address, .ndo_eth_ioctl = fec_enet_ioctl, -#ifdef CONFIG_NET_POLL_CONTROLLER - .ndo_poll_controller = fec_poll_controller, -#endif .ndo_set_features = fec_set_features, };

[ Sasha's backport helper bot ]

Hi,

✅ All tests passed successfully. No issues detected. No action required from the submitter.

The upstream commit SHA1 provided is correct: c2e0c58b25a0a0c37ec643255558c5af4450c9f5

WARNING: Author mismatch between patch and upstream commit: Backport author: Feng LiuFeng.Liu3@windriver.com Commit author: Wei Fangwei.fang@nxp.com

Status in newer kernel trees: 6.14.y | Present (exact SHA1) 6.12.y | Present (exact SHA1) 6.6.y | Present (different SHA1: d38625f71950) 6.1.y | Present (different SHA1: e2348d8c61d0) 5.15.y | Not found

Note: The patch differs from the upstream commit: --- 1: c2e0c58b25a0a ! 1: 4c81ce68d2ac2 net: fec: remove .ndo_poll_controller to avoid deadlocks @@ Metadata ## Commit message ## net: fec: remove .ndo_poll_controller to avoid deadlocks

+ [ Upstream commit c2e0c58b25a0a0c37ec643255558c5af4450c9f5 ] + There is a deadlock issue found in sungem driver, please refer to the commit ac0a230f719b ("eth: sungem: remove .ndo_poll_controller to avoid deadlocks"). The root cause of the issue is that netpoll is in atomic @@ Commit message Signed-off-by: Wei Fang wei.fang@nxp.com Link: https://lore.kernel.org/r/20240511062009.652918-1-wei.fang@nxp.com Signed-off-by: Jakub Kicinski kuba@kernel.org + [Minor context change fixed] + Signed-off-by: Feng Liu Feng.Liu3@windriver.com + Signed-off-by: He Zhe Zhe.He@windriver.com

## drivers/net/ethernet/freescale/fec_main.c ## @@ drivers/net/ethernet/freescale/fec_main.c: fec_set_mac_address(struct net_device *ndev, void *p) @@ drivers/net/ethernet/freescale/fec_main.c: fec_set_mac_address(struct net_device @@ drivers/net/ethernet/freescale/fec_main.c: static const struct net_device_ops fec_netdev_ops = { .ndo_tx_timeout = fec_timeout, .ndo_set_mac_address = fec_set_mac_address, - .ndo_eth_ioctl = phy_do_ioctl_running, + .ndo_do_ioctl = fec_enet_ioctl, -#ifdef CONFIG_NET_POLL_CONTROLLER - .ndo_poll_controller = fec_poll_controller, -#endif .ndo_set_features = fec_set_features, - .ndo_bpf = fec_enet_bpf, - .ndo_xdp_xmit = fec_enet_xdp_xmit, + }; + ---

Results of testing on various branches:

| Branch | Patch Apply | Build Test | |---------------------------|-------------|------------| | stable/linux-5.10.y | Success | Success |