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net: ti: icssg-prueth: Fix kernel panic during concurrent Tx queue access

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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: 62aa3246f4 ("net: ti: icssg-prueth: Add XDP support")
Signed-off-by: Meghana Malladi <m-malladi@ti.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Link: https://patch.msgid.link/20250506110546.4065715-3-m-malladi@ti.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Meghana Malladi
2025-05-06 16:35:45 +05:30
committed by Jakub Kicinski
parent e5641daa0e
commit 8b3fae3e23
2 changed files with 12 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

7
drivers/net/ethernet/ti/icssg/icssg_common.c
View File

@@ -650,6 +650,8 @@ 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;
@@ -669,8 +671,11 @@ 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;

7
drivers/net/ethernet/ti/icssg/icssg_prueth.c
View File

@@ -1075,17 +1075,21 @@ 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;
__netif_tx_lock(netif_txq, cpu);
for (i = 0; i < n; i++) {
xdpf = frames[i];
err = emac_xmit_xdp_frame(emac, xdpf, NULL, q_idx);
@@ -1095,6 +1099,7 @@ static int emac_xdp_xmit(struct net_device *dev, int n, struct xdp_frame **frame
}
nxmit++;
}
__netif_tx_unlock(netif_txq);
return nxmit;
}