This is a note to let you know that I've just added the patch titled net: dsa: microchip: provide a list of valid protocols for xmit handler 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-dsa-microchip-provide-a-list-of-valid-protocols-.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 16ef2ec6ffbf217c6a72fe1393b3f8b80e9122d1 Author: Sean Nyekjaer <sean@xxxxxxxxxx> Date: Wed Dec 6 08:16:54 2023 +0100 net: dsa: microchip: provide a list of valid protocols for xmit handler [ Upstream commit 1499b89289bf272fd83cb296c82fb5519d0fe93f ] Provide a list of valid protocols for which the driver will provide it's deferred xmit handler. When using DSA_TAG_PROTO_KSZ8795 protocol, it does not provide a "connect" method, therefor ksz_connect() is not allocating ksz_tagger_data. This avoids the following null pointer dereference: ksz_connect_tag_protocol from dsa_register_switch+0x9ac/0xee0 dsa_register_switch from ksz_switch_register+0x65c/0x828 ksz_switch_register from ksz_spi_probe+0x11c/0x168 ksz_spi_probe from spi_probe+0x84/0xa8 spi_probe from really_probe+0xc8/0x2d8 Fixes: ab32f56a4100 ("net: dsa: microchip: ptp: add packet transmission timestamping") Signed-off-by: Sean Nyekjaer <sean@xxxxxxxxxx> Reviewed-by: Florian Fainelli <florian.fainelli@xxxxxxxxxxxx> Reviewed-by: Vladimir Oltean <vladimir.oltean@xxxxxxx> Link: https://lore.kernel.org/r/20231206071655.1626479-1-sean@xxxxxxxxxx Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/net/dsa/microchip/ksz_common.c b/drivers/net/dsa/microchip/ksz_common.c index 42db7679c3606..286e20f340e5c 100644 --- a/drivers/net/dsa/microchip/ksz_common.c +++ b/drivers/net/dsa/microchip/ksz_common.c @@ -2624,10 +2624,18 @@ static int ksz_connect_tag_protocol(struct dsa_switch *ds, { struct ksz_tagger_data *tagger_data; - tagger_data = ksz_tagger_data(ds); - tagger_data->xmit_work_fn = ksz_port_deferred_xmit; - - return 0; + switch (proto) { + case DSA_TAG_PROTO_KSZ8795: + return 0; + case DSA_TAG_PROTO_KSZ9893: + case DSA_TAG_PROTO_KSZ9477: + case DSA_TAG_PROTO_LAN937X: + tagger_data = ksz_tagger_data(ds); + tagger_data->xmit_work_fn = ksz_port_deferred_xmit; + return 0; + default: + return -EPROTONOSUPPORT; + } } static int ksz_port_vlan_filtering(struct dsa_switch *ds, int port,