This is a note to let you know that I've just added the patch titled
net: enetc: Do not configure preemptible TCs if SIs do not support
to the 6.6-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:
net-enetc-do-not-configure-preemptible-tcs-if-sis-do.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit d5ecad4a6f4c6a54e1c388e0be84e9ae7b6fdf03
Author: Wei Fang <wei.fang@xxxxxxx>
Date: Mon Nov 25 17:07:19 2024 +0800
net: enetc: Do not configure preemptible TCs if SIs do not support
[ Upstream commit b2420b8c81ec674552d00c55d46245e5c184b260 ]
Both ENETC PF and VF drivers share enetc_setup_tc_mqprio() to configure
MQPRIO. And enetc_setup_tc_mqprio() calls enetc_change_preemptible_tcs()
to configure preemptible TCs. However, only PF is able to configure
preemptible TCs. Because only PF has related registers, while VF does not
have these registers. So for VF, its hw->port pointer is NULL. Therefore,
VF will access an invalid pointer when accessing a non-existent register,
which will cause a crash issue. The simplified log is as follows.
root@ls1028ardb:~# tc qdisc add dev eno0vf0 parent root handle 100: \
mqprio num_tc 4 map 0 0 1 1 2 2 3 3 queues 1@0 1@1 1@2 1@3 hw 1
[ 187.290775] Unable to handle kernel paging request at virtual address 0000000000001f00
[ 187.424831] pc : enetc_mm_commit_preemptible_tcs+0x1c4/0x400
[ 187.430518] lr : enetc_mm_commit_preemptible_tcs+0x30c/0x400
[ 187.511140] Call trace:
[ 187.513588] enetc_mm_commit_preemptible_tcs+0x1c4/0x400
[ 187.518918] enetc_setup_tc_mqprio+0x180/0x214
[ 187.523374] enetc_vf_setup_tc+0x1c/0x30
[ 187.527306] mqprio_enable_offload+0x144/0x178
[ 187.531766] mqprio_init+0x3ec/0x668
[ 187.535351] qdisc_create+0x15c/0x488
[ 187.539023] tc_modify_qdisc+0x398/0x73c
[ 187.542958] rtnetlink_rcv_msg+0x128/0x378
[ 187.547064] netlink_rcv_skb+0x60/0x130
[ 187.550910] rtnetlink_rcv+0x18/0x24
[ 187.554492] netlink_unicast+0x300/0x36c
[ 187.558425] netlink_sendmsg+0x1a8/0x420
[ 187.606759] ---[ end trace 0000000000000000 ]---
In addition, some PFs also do not support configuring preemptible TCs,
such as eno1 and eno3 on LS1028A. It won't crash like it does for VFs,
but we should prevent these PFs from accessing these unimplemented
registers.
Fixes: 827145392a4a ("net: enetc: only commit preemptible TCs to hardware when MM TX is active")
Signed-off-by: Wei Fang <wei.fang@xxxxxxx>
Suggested-by: Vladimir Oltean <vladimir.oltean@xxxxxxx>
Reviewed-by: Frank Li <Frank.Li@xxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/net/ethernet/freescale/enetc/enetc.c b/drivers/net/ethernet/freescale/enetc/enetc.c
index c17b9e3385168..87b27bd7a13bb 100644
--- a/drivers/net/ethernet/freescale/enetc/enetc.c
+++ b/drivers/net/ethernet/freescale/enetc/enetc.c
@@ -28,6 +28,9 @@ EXPORT_SYMBOL_GPL(enetc_port_mac_wr);
static void enetc_change_preemptible_tcs(struct enetc_ndev_priv *priv,
u8 preemptible_tcs)
{
+ if (!(priv->si->hw_features & ENETC_SI_F_QBU))
+ return;
+
priv->preemptible_tcs = preemptible_tcs;
enetc_mm_commit_preemptible_tcs(priv);
}
