KMSAN reported the following uninit-value access issue: lo speed is unknown, defaulting to 1000 ===================================================== BUG: KMSAN: uninit-value in ib_get_width_and_speed drivers/infiniband/core/verbs.c:1889 [inline] BUG: KMSAN: uninit-value in ib_get_eth_speed+0x546/0xaf0 drivers/infiniband/core/verbs.c:1998 ib_get_width_and_speed drivers/infiniband/core/verbs.c:1889 [inline] ib_get_eth_speed+0x546/0xaf0 drivers/infiniband/core/verbs.c:1998 siw_query_port drivers/infiniband/sw/siw/siw_verbs.c:173 [inline] siw_get_port_immutable+0x6f/0x120 drivers/infiniband/sw/siw/siw_verbs.c:203 setup_port_data drivers/infiniband/core/device.c:848 [inline] setup_device drivers/infiniband/core/device.c:1244 [inline] ib_register_device+0x1589/0x1df0 drivers/infiniband/core/device.c:1383 siw_device_register drivers/infiniband/sw/siw/siw_main.c:72 [inline] siw_newlink+0x129e/0x13d0 drivers/infiniband/sw/siw/siw_main.c:490 nldev_newlink+0x8fd/0xa60 drivers/infiniband/core/nldev.c:1763 rdma_nl_rcv_skb drivers/infiniband/core/netlink.c:239 [inline] rdma_nl_rcv+0xe8a/0x1120 drivers/infiniband/core/netlink.c:259 netlink_unicast_kernel net/netlink/af_netlink.c:1342 [inline] netlink_unicast+0xf4b/0x1230 net/netlink/af_netlink.c:1368 netlink_sendmsg+0x1242/0x1420 net/netlink/af_netlink.c:1910 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] ____sys_sendmsg+0x997/0xd60 net/socket.c:2588 ___sys_sendmsg+0x271/0x3b0 net/socket.c:2642 __sys_sendmsg net/socket.c:2671 [inline] __do_sys_sendmsg net/socket.c:2680 [inline] __se_sys_sendmsg net/socket.c:2678 [inline] __x64_sys_sendmsg+0x2fa/0x4a0 net/socket.c:2678 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x63/0x6b Local variable lksettings created at: ib_get_eth_speed+0x4b/0xaf0 drivers/infiniband/core/verbs.c:1974 siw_query_port drivers/infiniband/sw/siw/siw_verbs.c:173 [inline] siw_get_port_immutable+0x6f/0x120 drivers/infiniband/sw/siw/siw_verbs.c:203 CPU: 0 PID: 11257 Comm: syz-executor.1 Not tainted 6.6.0-14500-g1c41041124bd #10 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-1.fc38 04/01/2014 ===================================================== If __ethtool_get_link_ksettings() fails, `netdev_speed` is set to the default value, SPEED_1000. In this case, if `lanes` field of struct ethtool_link_ksettings is not initialized, an uninitialized value is passed to ib_get_width_and_speed(). This causes the above issue. This patch resolves the issue by initializing `lanes` to 0. Fixes: cb06b6b3f6cb ("RDMA/core: Get IB width and speed from netdev") Signed-off-by: Shigeru Yoshida <syoshida@xxxxxxxxxx> --- drivers/infiniband/core/verbs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/infiniband/core/verbs.c b/drivers/infiniband/core/verbs.c index 8a6da87f464b..4fb585c23a2e 100644 --- a/drivers/infiniband/core/verbs.c +++ b/drivers/infiniband/core/verbs.c @@ -1971,7 +1971,7 @@ int ib_get_eth_speed(struct ib_device *dev, u32 port_num, u16 *speed, u8 *width) int rc; u32 netdev_speed; struct net_device *netdev; - struct ethtool_link_ksettings lksettings; + struct ethtool_link_ksettings lksettings = { .lanes = 0 }; if (rdma_port_get_link_layer(dev, port_num) != IB_LINK_LAYER_ETHERNET) return -EINVAL; -- 2.41.0