[PATCH 6.18 086/198] ixgbevf: add missing negotiate_features op to Hyper-V ops table

Greg Kroah-Hartman
2026-04-20T16:00:54Z

From: Michal Schmidt <mschmidt@redhat.com>

[ Upstream commit 4821d563cd7f251ae728be1a6d04af82a294a5b9 ]

Commit a7075f501bd3 ("ixgbevf: fix mailbox API compatibility by
negotiating supported features") added the .negotiate_features callback
to ixgbe_mac_operations and populated it in ixgbevf_mac_ops, but forgot
to add it to ixgbevf_hv_mac_ops. This leaves the function pointer NULL
on Hyper-V VMs.

During probe, ixgbevf_negotiate_api() calls ixgbevf_set_features(),
which unconditionally dereferences hw->mac.ops.negotiate_features().
On Hyper-V this results in a NULL pointer dereference:

BUG: kernel NULL pointer dereference, address: 0000000000000000
[...]
Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine [...]
Workqueue: events work_for_cpu_fn
RIP: 0010:0x0
[...]
Call Trace:
ixgbevf_negotiate_api+0x66/0x160 [ixgbevf]
ixgbevf_sw_init+0xe4/0x1f0 [ixgbevf]
ixgbevf_probe+0x20f/0x4a0 [ixgbevf]
local_pci_probe+0x50/0xa0
work_for_cpu_fn+0x1a/0x30
[...]

Add ixgbevf_hv_negotiate_features_vf() that returns -EOPNOTSUPP and
wire it into ixgbevf_hv_mac_ops. The caller already handles -EOPNOTSUPP
gracefully.

Fixes: a7075f501bd3 ("ixgbevf: fix mailbox API compatibility by negotiating supported features")
Reported-by: Xiaoqiang Xiong <xxiong@redhat.com>
Closes: https://issues.redhat.com/browse/RHEL-155455
Assisted-by: Claude:claude-4.6-opus-high Cursor
Tested-by: Xiaoqiang Xiong <xxiong@redhat.com>
Signed-off-by: Michal Schmidt <mschmidt@redhat.com>
Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/ethernet/intel/ixgbevf/vf.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/drivers/net/ethernet/intel/ixgbevf/vf.c b/drivers/net/ethernet/intel/ixgbevf/vf.c
index b67b580f7f1c9..f6df86d124b9e 100644
--- a/drivers/net/ethernet/intel/ixgbevf/vf.c
+++ b/drivers/net/ethernet/intel/ixgbevf/vf.c
@@ -709,6 +709,12 @@ static int ixgbevf_negotiate_features_vf(struct ixgbe_hw *hw, u32 *pf_features)
return err;
}

+static int ixgbevf_hv_negotiate_features_vf(struct ixgbe_hw *hw,
+ u32 *pf_features)
+{
+ return -EOPNOTSUPP;
+}
+
/**
* ixgbevf_set_vfta_vf - Set/Unset VLAN filter table address
* @hw: pointer to the HW structure
@@ -1142,6 +1148,7 @@ static const struct ixgbe_mac_operations ixgbevf_hv_mac_ops = {
.setup_link = ixgbevf_setup_mac_link_vf,
.check_link = ixgbevf_hv_check_mac_link_vf,
.negotiate_api_version = ixgbevf_hv_negotiate_api_version_vf,
+ .negotiate_features = ixgbevf_hv_negotiate_features_vf,
.set_rar = ixgbevf_hv_set_rar_vf,
.update_mc_addr_list = ixgbevf_hv_update_mc_addr_list_vf,
.update_xcast_mode = ixgbevf_hv_update_xcast_mode,
--
2.53.0