| Message ID | 20220914111135.21038-1-ihuguet@redhat.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 0a242eb2913a4aa3d6fbdb86559f27628e9466f3 |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net] sfc: fix null pointer dereference in efx_hard_start_xmit | expand |
On 14/09/2022 12:11, Íñigo Huguet wrote: > Trying to get the channel from the tx_queue variable here is wrong > because we can only be here if tx_queue is NULL, so we shouldn't > dereference it. As the above comment in the code says, this is very > unlikely to happen, but it's wrong anyway so let's fix it. > > I hit this issue because of a different bug that caused tx_queue to be > NULL. If that happens, this is the error message that we get here: > BUG: unable to handle kernel NULL pointer dereference at 0000000000000020 > [...] > RIP: 0010:efx_hard_start_xmit+0x153/0x170 [sfc] > > Fixes: 12804793b17c ("sfc: decouple TXQ type from label") > Reported-by: Tianhao Zhao <tizhao@redhat.com> > Signed-off-by: Íñigo Huguet <ihuguet@redhat.com> Acked-by: Edward Cree <ecree.xilinx@gmail.com>
Hello: This patch was applied to netdev/net.git (master) by Jakub Kicinski <kuba@kernel.org>: On Wed, 14 Sep 2022 13:11:35 +0200 you wrote: > Trying to get the channel from the tx_queue variable here is wrong > because we can only be here if tx_queue is NULL, so we shouldn't > dereference it. As the above comment in the code says, this is very > unlikely to happen, but it's wrong anyway so let's fix it. > > I hit this issue because of a different bug that caused tx_queue to be > NULL. If that happens, this is the error message that we get here: > BUG: unable to handle kernel NULL pointer dereference at 0000000000000020 > [...] > RIP: 0010:efx_hard_start_xmit+0x153/0x170 [sfc] > > [...] Here is the summary with links: - [net] sfc: fix null pointer dereference in efx_hard_start_xmit https://git.kernel.org/netdev/net/c/0a242eb2913a You are awesome, thank you!
diff --git a/drivers/net/ethernet/sfc/tx.c b/drivers/net/ethernet/sfc/tx.c index d12474042c84..c5f88f7a7a04 100644 --- a/drivers/net/ethernet/sfc/tx.c +++ b/drivers/net/ethernet/sfc/tx.c @@ -549,7 +549,7 @@ netdev_tx_t efx_hard_start_xmit(struct sk_buff *skb, * previous packets out. */ if (!netdev_xmit_more()) - efx_tx_send_pending(tx_queue->channel); + efx_tx_send_pending(efx_get_tx_channel(efx, index)); return NETDEV_TX_OK; }
Trying to get the channel from the tx_queue variable here is wrong because we can only be here if tx_queue is NULL, so we shouldn't dereference it. As the above comment in the code says, this is very unlikely to happen, but it's wrong anyway so let's fix it. I hit this issue because of a different bug that caused tx_queue to be NULL. If that happens, this is the error message that we get here: BUG: unable to handle kernel NULL pointer dereference at 0000000000000020 [...] RIP: 0010:efx_hard_start_xmit+0x153/0x170 [sfc] Fixes: 12804793b17c ("sfc: decouple TXQ type from label") Reported-by: Tianhao Zhao <tizhao@redhat.com> Signed-off-by: Íñigo Huguet <ihuguet@redhat.com> --- drivers/net/ethernet/sfc/tx.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)