In the previous implementation, vf_state is allocated memory only when VF
is enabled. However, net_device_ops::ndo_set_vf_mac() may be called before
VF is enabled to configure the MAC address of VF. If this is the case,
enetc_pf_set_vf_mac() will access vf_state, resulting in access to a null
pointer. The simplified error log is as follows.

root@ls1028ardb:~# ip link set eno0 vf 1 mac 00:0c:e7:66:77:89
[  173.543315] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000004
[  173.637254] pc : enetc_pf_set_vf_mac+0x3c/0x80 Message from sy
[  173.641973] lr : do_setlink+0x4a8/0xec8
[  173.732292] Call trace:
[  173.734740]  enetc_pf_set_vf_mac+0x3c/0x80
[  173.738847]  __rtnl_newlink+0x530/0x89c
[  173.742692]  rtnl_newlink+0x50/0x7c
[  173.746189]  rtnetlink_rcv_msg+0x128/0x390
[  173.750298]  netlink_rcv_skb+0x60/0x130
[  173.754145]  rtnetlink_rcv+0x18/0x24
[  173.757731]  netlink_unicast+0x318/0x380
[  173.761665]  netlink_sendmsg+0x17c/0x3c8

Fixes: d4fd0404c1c9 ("enetc: Introduce basic PF and VF ENETC ethernet drivers")
Signed-off-by: Wei Fang <wei.fang@nxp.com>
---
 .../net/ethernet/freescale/enetc/enetc_pf.c    | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/net/ethernet/freescale/enetc/enetc_pf.c b/drivers/net/ethernet/freescale/enetc/enetc_pf.c
index 8f6b0bf48139..c95a7c083b0f 100644
--- a/drivers/net/ethernet/freescale/enetc/enetc_pf.c
+++ b/drivers/net/ethernet/freescale/enetc/enetc_pf.c
@@ -665,19 +665,11 @@ static int enetc_sriov_configure(struct pci_dev *pdev, int num_vfs)
 
 	if (!num_vfs) {
 		enetc_msg_psi_free(pf);
-		kfree(pf->vf_state);
 		pf->num_vfs = 0;
 		pci_disable_sriov(pdev);
 	} else {
 		pf->num_vfs = num_vfs;
 
-		pf->vf_state = kcalloc(num_vfs, sizeof(struct enetc_vf_state),
-				       GFP_KERNEL);
-		if (!pf->vf_state) {
-			pf->num_vfs = 0;
-			return -ENOMEM;
-		}
-
 		err = enetc_msg_psi_init(pf);
 		if (err) {
 			dev_err(&pdev->dev, "enetc_msg_psi_init (%d)\n", err);
@@ -696,7 +688,6 @@ static int enetc_sriov_configure(struct pci_dev *pdev, int num_vfs)
 err_en_sriov:
 	enetc_msg_psi_free(pf);
 err_msg_psi:
-	kfree(pf->vf_state);
 	pf->num_vfs = 0;
 
 	return err;
@@ -1286,6 +1277,12 @@ static int enetc_pf_probe(struct pci_dev *pdev,
 	pf = enetc_si_priv(si);
 	pf->si = si;
 	pf->total_vfs = pci_sriov_get_totalvfs(pdev);
+	if (pf->total_vfs) {
+		pf->vf_state = kcalloc(pf->total_vfs, sizeof(struct enetc_vf_state),
+				       GFP_KERNEL);
+		if (!pf->vf_state)
+			goto err_alloc_vf_state;
+	}
 
 	err = enetc_setup_mac_addresses(node, pf);
 	if (err)
@@ -1363,6 +1360,8 @@ static int enetc_pf_probe(struct pci_dev *pdev,
 	free_netdev(ndev);
 err_alloc_netdev:
 err_setup_mac_addresses:
+	kfree(pf->vf_state);
+err_alloc_vf_state:
 	enetc_psi_destroy(pdev);
 err_psi_create:
 	return err;
@@ -1389,6 +1388,7 @@ static void enetc_pf_remove(struct pci_dev *pdev)
 	enetc_free_si_resources(priv);
 
 	free_netdev(si->ndev);
+	kfree(pf->vf_state);
 
 	enetc_psi_destroy(pdev);
 }
-- 
2.34.1

On Thu, Oct 31, 2024 at 02:02:46PM +0800, Wei Fang wrote:
> In the previous implementation, vf_state is allocated memory only when VF
> is enabled. However, net_device_ops::ndo_set_vf_mac() may be called before
> VF is enabled to configure the MAC address of VF. If this is the case,
> enetc_pf_set_vf_mac() will access vf_state, resulting in access to a null
> pointer. The simplified error log is as follows.
> 
> root@ls1028ardb:~# ip link set eno0 vf 1 mac 00:0c:e7:66:77:89
> [  173.543315] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000004
> [  173.637254] pc : enetc_pf_set_vf_mac+0x3c/0x80 Message from sy
> [  173.641973] lr : do_setlink+0x4a8/0xec8
> [  173.732292] Call trace:
> [  173.734740]  enetc_pf_set_vf_mac+0x3c/0x80
> [  173.738847]  __rtnl_newlink+0x530/0x89c
> [  173.742692]  rtnl_newlink+0x50/0x7c
> [  173.746189]  rtnetlink_rcv_msg+0x128/0x390
> [  173.750298]  netlink_rcv_skb+0x60/0x130
> [  173.754145]  rtnetlink_rcv+0x18/0x24
> [  173.757731]  netlink_unicast+0x318/0x380
> [  173.761665]  netlink_sendmsg+0x17c/0x3c8
> 
> Fixes: d4fd0404c1c9 ("enetc: Introduce basic PF and VF ENETC ethernet drivers")
> Signed-off-by: Wei Fang <wei.fang@nxp.com>
> ---

Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Tested-by: Vladimir Oltean <vladimir.oltean@nxp.com>