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| author | Sebastian Andrzej Siewior <bigeasy@linutronix.de> | 2024-10-02 14:58:37 +0200 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2024-10-03 15:42:00 -0700 |
| commit | 55e802468e1d38dec8e25a2fdb6078d45b647e8c (patch) | |
| tree | 5d20bf8d3a9f311bdd625ce3afbe990f33204662 | |
| parent | a842e443ca8184f2dc82ab307b43a8b38defd6a5 (diff) | |
| download | lwn-55e802468e1d38dec8e25a2fdb6078d45b647e8c.tar.gz lwn-55e802468e1d38dec8e25a2fdb6078d45b647e8c.zip | |
sfc: Don't invoke xdp_do_flush() from netpoll.
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@unformed.ru>
Closes: https://lore.kernel.org/5627f6d1-5491-4462-9d75-bc0612c26a22@app.fastmail.com
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Edward Cree <ecree.xilinx@gmail.com>
Link: https://patch.msgid.link/20241002125837.utOcRo6Y@linutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | drivers/net/ethernet/sfc/efx_channels.c | 3 | ||||
| -rw-r--r-- | drivers/net/ethernet/sfc/siena/efx_channels.c | 3 |
2 files changed, 4 insertions, 2 deletions
diff --git a/drivers/net/ethernet/sfc/efx_channels.c b/drivers/net/ethernet/sfc/efx_channels.c index c9e17a8208a9..f1723a6fb082 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 a7346e965bfe..d120b3c83ac0 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) && |