This is a note to let you know that I've just added the patch titled
sfc: Don't invoke xdp_do_flush() from netpoll.
to the 6.11-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
sfc-don-t-invoke-xdp_do_flush-from-netpoll.patch
and it can be found in the queue-6.11 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 74d5045a9a5497d20116195a9a54f9da6fd4d982
Author: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Date: Wed Oct 2 14:58:37 2024 +0200
sfc: Don't invoke xdp_do_flush() from netpoll.
[ Upstream commit 55e802468e1d38dec8e25a2fdb6078d45b647e8c ]
Yury reported a crash in the sfc driver originated from
netpoll_send_udp(). The netconsole sends a message and then netpoll
invokes the driver's NAPI function with a budget of zero. It is
dedicated to allow driver to free TX resources, that it may have used
while sending the packet.
In the netpoll case the driver invokes xdp_do_flush() unconditionally,
leading to crash because bpf_net_context was never assigned.
Invoke xdp_do_flush() only if budget is not zero.
Fixes: 401cb7dae8130 ("net: Reference bpf_redirect_info via task_struct on PREEMPT_RT.")
Reported-by: Yury Vostrikov <mon@xxxxxxxxxxx>
Closes: https://lore.kernel.org/5627f6d1-5491-4462-9d75-bc0612c26a22@xxxxxxxxxxxxxxxx
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Reviewed-by: Edward Cree <ecree.xilinx@xxxxxxxxx>
Link: https://patch.msgid.link/20241002125837.utOcRo6Y@xxxxxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/net/ethernet/sfc/efx_channels.c b/drivers/net/ethernet/sfc/efx_channels.c
index c9e17a8208a90..f1723a6fb082b 100644
--- a/drivers/net/ethernet/sfc/efx_channels.c
+++ b/drivers/net/ethernet/sfc/efx_channels.c
@@ -1260,7 +1260,8 @@ static int efx_poll(struct napi_struct *napi, int budget)
spent = efx_process_channel(channel, budget);
- xdp_do_flush();
+ if (budget)
+ xdp_do_flush();
if (spent < budget) {
if (efx_channel_has_rx_queue(channel) &&
diff --git a/drivers/net/ethernet/sfc/siena/efx_channels.c b/drivers/net/ethernet/sfc/siena/efx_channels.c
index a7346e965bfe7..d120b3c83ac07 100644
--- a/drivers/net/ethernet/sfc/siena/efx_channels.c
+++ b/drivers/net/ethernet/sfc/siena/efx_channels.c
@@ -1285,7 +1285,8 @@ static int efx_poll(struct napi_struct *napi, int budget)
spent = efx_process_channel(channel, budget);
- xdp_do_flush();
+ if (budget)
+ xdp_do_flush();
if (spent < budget) {
if (efx_channel_has_rx_queue(channel) &&
