[PATCH v5] kni: fix device address set

[Min Hu (Connor)]

Currently, run KNI APP When Kernel version is 5.17. When quit the APP,
dmesg buffer get calltrace, info like:
[ 5965.847401] rte_kni: Creating kni...
[ 6225.627205] vEth0 (unregistered): Current addr:  70 fd 45 d0 72 a7 00..
[ 6225.640113] vEth0 (unregistered): Expected addr: 00 00 00 00 00 00 00..
[ 6225.653010] ------------[ cut here ]------------
[ 6225.657609] netdevice: vEth0 (unregistered): Incorrect netdev->dev_addr
[ 6225.832647] Call trace:
[ 6225.835083]  dev_addr_check+0xa0/0x144
[ 6225.838816]  dev_addr_flush+0x30/0x9c
[ 6225.842462]  free_netdev+0x8c/0x1e0
[ 6225.845939]  kni_release+0xc0/0x1d0 [rte_kni]
[ 6225.850281]  __fput+0x78/0x220
[ 6225.853327]  ____fput+0x1c/0x30
[ 6225.856455]  task_work_run+0x88/0xc0
[ 6225.860017]  do_exit+0x2fc/0x940
[ 6225.863232]  do_group_exit+0x40/0xac
[ 6225.866791]  get_signal+0x190/0x960
[ 6225.870265]  do_notify_resume+0x26c/0x1360
[ 6225.874346]  el0_interrupt+0x60/0xe0
[ 6225.877910]  __el0_irq_handler_common+0x18/0x24
[ 6225.882420]  el0t_64_irq_handler+0x14/0x20
[ 6225.886499]  el0t_64_irq+0x1a0/0x1a4
[ 6225.890059] ---[ end trace 0000000000000000 ]---
[ 6245.598157] rte_kni: Creating kni...

The reason is that 5.17 kernel introduce 'dev_addr_shadow' in function
'dev_addr_set' to ensure that netdev->dev_addr should only be modified
via helpers('dev_addr_set'). 'dev_addr_check' will check if
netdev->dev_addr is modified by other ways, like 'memcpy'.

More info could get by referring to kernel patch:
https://patchwork.kernel.org/project/netdevbpf/patch/
20211118041501.3102861-8-kuba at kernel.org/
https://www.spinics.net/lists/netdev/msg764992.html

Fixes: ea6b39b5b847 ("kni: remove ethtool support")

Signed-off-by: Min Hu (Connor) <humin29 at huawei.com>
---
v5:
* define 'HAVE_DEV_ADDR_SHADOW'.

v3,v4:
* fix compiling errors.

v2:
* change 'memcpy' to 'ether_addr_copy' to copy device addr.
---
 kernel/linux/kni/compat.h   |  4 ++++
 kernel/linux/kni/kni_misc.c | 10 ++++++++--
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/kernel/linux/kni/compat.h b/kernel/linux/kni/compat.h
index 664785674f..7ffca63bd4 100644
--- a/kernel/linux/kni/compat.h
+++ b/kernel/linux/kni/compat.h
@@ -141,3 +141,7 @@
 #if KERNEL_VERSION(5, 9, 0) > LINUX_VERSION_CODE
 #define HAVE_TSK_IN_GUP
 #endif
+
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 17, 0)
+#define HAVE_DEV_ADDR_SHADOW
+#endif
diff --git a/kernel/linux/kni/kni_misc.c b/kernel/linux/kni/kni_misc.c
index 780187d8bf..0470d349c5 100644
--- a/kernel/linux/kni/kni_misc.c
+++ b/kernel/linux/kni/kni_misc.c
@@ -299,6 +299,7 @@ kni_ioctl_create(struct net *net, uint32_t ioctl_num,
 	struct kni_net *knet = net_generic(net, kni_net_id);
 	int ret;
 	struct rte_kni_device_info dev_info;
+	unsigned char mac_addr[ETH_ALEN];
 	struct net_device *net_dev = NULL;
 	struct kni_dev *kni, *dev, *n;
 
@@ -403,10 +404,15 @@ kni_ioctl_create(struct net *net, uint32_t ioctl_num,
 
 	/* if user has provided a valid mac address */
 	if (is_valid_ether_addr(dev_info.mac_addr))
-		memcpy(net_dev->dev_addr, dev_info.mac_addr, ETH_ALEN);
+		ether_addr_copy(mac_addr, dev_info.mac_addr);
 	else
 		/* Generate random MAC address. */
-		eth_random_addr(net_dev->dev_addr);
+		eth_random_addr(mac_addr);
+#ifdef HAVE_DEV_ADDR_SHADOW
+	dev_addr_set(net_dev, mac_addr);
+#else
+	ether_addr_copy(net_dev->dev_addr, mac_addr);
+#endif
 
 	if (dev_info.mtu)
 		net_dev->mtu = dev_info.mtu;
-- 
2.33.0