Add __netif_tx_lock() to ensure that only one packet is being transmitted at a time to avoid race conditions in the netif_txq struct and prevent packet data corruption. Failing to do so causes kernel panic with the following error: [ 2184.746764] ------------[ cut here ]------------ [ 2184.751412] kernel BUG at lib/dynamic_queue_limits.c:99! [ 2184.756728] Internal error: Oops - BUG: 00000000f2000800 [#1] PREEMPT SMP logs: https://gist.github.com/MeghanaMalladiTI/9c7aa5fc3b7fb03f87c74aad487956e9 The lock is acquired before calling emac_xmit_xdp_frame() and released after the call returns. This ensures that the TX queue is protected from concurrent access during the transmission of XDP frames. Fixes: 62aa3246f462 ("net: ti: icssg-prueth: Add XDP support") Signed-off-by: Meghana Malladi <m-malladi@xxxxxx> --- drivers/net/ethernet/ti/icssg/icssg_common.c | 7 ++++++- drivers/net/ethernet/ti/icssg/icssg_prueth.c | 7 ++++++- 2 files changed, 12 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/ti/icssg/icssg_common.c b/drivers/net/ethernet/ti/icssg/icssg_common.c index a120ff6fec8f..e509b6ff81e7 100644 --- a/drivers/net/ethernet/ti/icssg/icssg_common.c +++ b/drivers/net/ethernet/ti/icssg/icssg_common.c @@ -660,6 +660,8 @@ static u32 emac_run_xdp(struct prueth_emac *emac, struct xdp_buff *xdp, struct page *page, u32 *len) { struct net_device *ndev = emac->ndev; + struct netdev_queue *netif_txq; + int cpu = smp_processor_id(); struct bpf_prog *xdp_prog; struct xdp_frame *xdpf; u32 pkt_len = *len; @@ -679,8 +681,11 @@ static u32 emac_run_xdp(struct prueth_emac *emac, struct xdp_buff *xdp, goto drop; } - q_idx = smp_processor_id() % emac->tx_ch_num; + q_idx = cpu % emac->tx_ch_num; + netif_txq = netdev_get_tx_queue(ndev, q_idx); + __netif_tx_lock(netif_txq, cpu); result = emac_xmit_xdp_frame(emac, xdpf, page, q_idx); + __netif_tx_unlock(netif_txq); if (result == ICSSG_XDP_CONSUMED) { ndev->stats.tx_dropped++; goto drop; diff --git a/drivers/net/ethernet/ti/icssg/icssg_prueth.c b/drivers/net/ethernet/ti/icssg/icssg_prueth.c index ee35fecf61e7..b31060e7f698 100644 --- a/drivers/net/ethernet/ti/icssg/icssg_prueth.c +++ b/drivers/net/ethernet/ti/icssg/icssg_prueth.c @@ -1075,20 +1075,25 @@ static int emac_xdp_xmit(struct net_device *dev, int n, struct xdp_frame **frame { struct prueth_emac *emac = netdev_priv(dev); struct net_device *ndev = emac->ndev; + struct netdev_queue *netif_txq; + int cpu = smp_processor_id(); struct xdp_frame *xdpf; unsigned int q_idx; int nxmit = 0; u32 err; int i; - q_idx = smp_processor_id() % emac->tx_ch_num; + q_idx = cpu % emac->tx_ch_num; + netif_txq = netdev_get_tx_queue(ndev, q_idx); if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK)) return -EINVAL; for (i = 0; i < n; i++) { xdpf = frames[i]; + __netif_tx_lock(netif_txq, cpu); err = emac_xmit_xdp_frame(emac, xdpf, NULL, q_idx); + __netif_tx_unlock(netif_txq); if (err != ICSSG_XDP_TX) { ndev->stats.tx_dropped++; break; -- 2.43.0
