[PATCH v3 1/2] net/ncsi: fix locking in Get MAC Address handling

Potin Lai
2025-01-13T02:37:30Z

From: Paul Fertser <fercerpav@gmail.com>

Obtaining RTNL lock in a response handler is not allowed since it runs
in an atomic softirq context. Postpone setting the MAC address by adding
a dedicated step to the configuration FSM.

Fixes: 790071347a0a ("net/ncsi: change from ndo_set_mac_address to dev_set_mac_address")
Cc: stable@vger.kernel.org
Cc: Potin Lai <potin.lai@quantatw.com>
Link: https://lore.kernel.org/20241129-potin-revert-ncsi-set-mac-addr-v1-1-94ea2cb596af@gmail.com
Signed-off-by: Paul Fertser <fercerpav@gmail.com>
---
net/ncsi/internal.h | 2 ++
net/ncsi/ncsi-manage.c | 16 ++++++++++++++--
net/ncsi/ncsi-rsp.c | 19 ++++++-------------
3 files changed, 22 insertions(+), 15 deletions(-)

diff --git a/net/ncsi/internal.h b/net/ncsi/internal.h
index ef0f8f73826f..4e0842df5234 100644
--- a/net/ncsi/internal.h
+++ b/net/ncsi/internal.h
@@ -289,6 +289,7 @@ enum {
ncsi_dev_state_config_sp = 0x0301,
ncsi_dev_state_config_cis,
ncsi_dev_state_config_oem_gma,
+ ncsi_dev_state_config_apply_mac,
ncsi_dev_state_config_clear_vids,
ncsi_dev_state_config_svf,
ncsi_dev_state_config_ev,
@@ -322,6 +323,7 @@ struct ncsi_dev_priv {
#define NCSI_DEV_RESHUFFLE 4
#define NCSI_DEV_RESET 8 /* Reset state of NC */
unsigned int gma_flag; /* OEM GMA flag */
+ struct sockaddr pending_mac; /* MAC address received from GMA */
spinlock_t lock; /* Protect the NCSI device */
unsigned int package_probe_id;/* Current ID during probe */
unsigned int package_num; /* Number of packages */
diff --git a/net/ncsi/ncsi-manage.c b/net/ncsi/ncsi-manage.c
index 5cf55bde366d..bf276eaf9330 100644
--- a/net/ncsi/ncsi-manage.c
+++ b/net/ncsi/ncsi-manage.c
@@ -1038,7 +1038,7 @@ static void ncsi_configure_channel(struct ncsi_dev_priv *ndp)
: ncsi_dev_state_config_clear_vids;
break;
case ncsi_dev_state_config_oem_gma:
- nd->state = ncsi_dev_state_config_clear_vids;
+ nd->state = ncsi_dev_state_config_apply_mac;

nca.package = np->id;
nca.channel = nc->id;
@@ -1050,10 +1050,22 @@ static void ncsi_configure_channel(struct ncsi_dev_priv *ndp)
nca.type = NCSI_PKT_CMD_OEM;
ret = ncsi_gma_handler(&nca, nc->version.mf_id);
}
- if (ret < 0)
+ if (ret < 0) {
+ nd->state = ncsi_dev_state_config_clear_vids;
schedule_work(&ndp->work);
+ }

break;
+ case ncsi_dev_state_config_apply_mac:
+ rtnl_lock();
+ ret = dev_set_mac_address(dev, &ndp->pending_mac, NULL);
+ rtnl_unlock();
+ if (ret < 0)
+ netdev_warn(dev, "NCSI: 'Writing MAC address to device failed\n");
+
+ nd->state = ncsi_dev_state_config_clear_vids;
+
+ fallthrough;
case ncsi_dev_state_config_clear_vids:
case ncsi_dev_state_config_svf:
case ncsi_dev_state_config_ev:
diff --git a/net/ncsi/ncsi-rsp.c b/net/ncsi/ncsi-rsp.c
index e28be33bdf2c..14bd66909ca4 100644
--- a/net/ncsi/ncsi-rsp.c
+++ b/net/ncsi/ncsi-rsp.c
@@ -628,16 +628,14 @@ static int ncsi_rsp_handler_snfc(struct ncsi_request *nr)
static int ncsi_rsp_handler_oem_gma(struct ncsi_request *nr, int mfr_id)
{
struct ncsi_dev_priv *ndp = nr->ndp;
+ struct sockaddr *saddr = &ndp->pending_mac;
struct net_device *ndev = ndp->ndev.dev;
struct ncsi_rsp_oem_pkt *rsp;
- struct sockaddr saddr;
u32 mac_addr_off = 0;
- int ret = 0;

/* Get the response header */
rsp = (struct ncsi_rsp_oem_pkt *)skb_network_header(nr->rsp);

- saddr.sa_family = ndev->type;
ndev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
if (mfr_id == NCSI_OEM_MFR_BCM_ID)
mac_addr_off = BCM_MAC_ADDR_OFFSET;
@@ -646,22 +644,17 @@ static int ncsi_rsp_handler_oem_gma(struct ncsi_request *nr, int mfr_id)
else if (mfr_id == NCSI_OEM_MFR_INTEL_ID)
mac_addr_off = INTEL_MAC_ADDR_OFFSET;

- memcpy(saddr.sa_data, &rsp->data[mac_addr_off], ETH_ALEN);
+ saddr->sa_family = ndev->type;
+ memcpy(saddr->sa_data, &rsp->data[mac_addr_off], ETH_ALEN);
if (mfr_id == NCSI_OEM_MFR_BCM_ID || mfr_id == NCSI_OEM_MFR_INTEL_ID)
- eth_addr_inc((u8 *)saddr.sa_data);
- if (!is_valid_ether_addr((const u8 *)saddr.sa_data))
+ eth_addr_inc((u8 *)saddr->sa_data);
+ if (!is_valid_ether_addr((const u8 *)saddr->sa_data))
return -ENXIO;

/* Set the flag for GMA command which should only be called once */
ndp->gma_flag = 1;

- rtnl_lock();
- ret = dev_set_mac_address(ndev, &saddr, NULL);
- rtnl_unlock();
- if (ret < 0)
- netdev_warn(ndev, "NCSI: 'Writing mac address to device failed\n");
-
- return ret;
+ return 0;
}

/* Response handler for Mellanox card */

--
2.31.1