The commit c23d92b80e0b ("igb: Teardown SR-IOV before
unregister_netdev()") places the unregister_netdev() call after the
igb_disable_sriov() call to avoid functionality issue.
However, it introduces several race conditions when detaching a device.
For example, when .remove() is called, the below interleaving leads to
use-after-free.
(FREE from device detaching) | (USE from netdev core)
igb_remove | igb_ndo_get_vf_config
igb_disable_sriov | vf >= adapter->vfs_allocated_count?
kfree(adapter->vf_data) |
adapter->vfs_allocated_count = 0 |
| memcpy(... adapter->vf_data[vf]
Moreover, the igb_disable_sriov() also suffers from data race with the
requests from VF driver.
(FREE from device detaching) | (USE from requests)
igb_remove | igb_msix_other
igb_disable_sriov | igb_msg_task
kfree(adapter->vf_data) | vf < adapter->vfs_allocated_count
adapter->vfs_allocated_count = 0 |
To this end, this commit first eliminates the data races from netdev
core by using rtnl_lock (similar to commit 719479230893 ("dpaa2-eth: add
MAC/PHY support through phylink")). And then adds a spinlock to
eliminate races from driver requests. (similar to commit 1e53834ce541
("ixgbe: Add locking to prevent panic when setting sriov_numvfs to zero")
Fixes: c23d92b80e0b ("igb: Teardown SR-IOV before unregister_netdev()")
Signed-off-by: Lin Ma <linma@xxxxxxxxxx>
---
V2 -> V3: make the commit message much clear
V1 -> V2: fix typo in title idb -> igb
V0 -> V1: change title from "Add rtnl_lock" to "Add lock"
add additional spinlock as suggested by Jakub, according to
1e53834ce541 ("ixgbe: Add locking to prevent panic when setting
sriov_numvfs to zero")
drivers/net/ethernet/intel/igb/igb.h | 2 ++
drivers/net/ethernet/intel/igb/igb_main.c | 12 +++++++++++-
2 files changed, 13 insertions(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/intel/igb/igb.h b/drivers/net/ethernet/intel/igb/igb.h
index 2d3daf022651..015b78144114 100644
--- a/drivers/net/ethernet/intel/igb/igb.h
+++ b/drivers/net/ethernet/intel/igb/igb.h
@@ -664,6 +664,8 @@ struct igb_adapter {
struct igb_mac_addr *mac_table;
struct vf_mac_filter vf_macs;
struct vf_mac_filter *vf_mac_list;
+ /* lock for VF resources */
+ spinlock_t vfs_lock;
};
/* flags controlling PTP/1588 function */
diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index d8b836a85cc3..2796e81d2726 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -3637,6 +3637,7 @@ static int igb_disable_sriov(struct pci_dev *pdev)
struct net_device *netdev = pci_get_drvdata(pdev);
struct igb_adapter *adapter = netdev_priv(netdev);
struct e1000_hw *hw = &adapter->hw;
+ unsigned long flags;
/* reclaim resources allocated to VFs */
if (adapter->vf_data) {
@@ -3649,12 +3650,13 @@ static int igb_disable_sriov(struct pci_dev *pdev)
pci_disable_sriov(pdev);
msleep(500);
}
-
+ spin_lock_irqsave(&adapter->vfs_lock, flags);
kfree(adapter->vf_mac_list);
adapter->vf_mac_list = NULL;
kfree(adapter->vf_data);
adapter->vf_data = NULL;
adapter->vfs_allocated_count = 0;
+ spin_unlock_irqrestore(&adapter->vfs_lock, flags);
wr32(E1000_IOVCTL, E1000_IOVCTL_REUSE_VFQ);
wrfl();
msleep(100);
@@ -3814,7 +3816,9 @@ static void igb_remove(struct pci_dev *pdev)
igb_release_hw_control(adapter);
#ifdef CONFIG_PCI_IOV
+ rtnl_lock();
igb_disable_sriov(pdev);
+ rtnl_unlock();
#endif
unregister_netdev(netdev);
@@ -3974,6 +3978,9 @@ static int igb_sw_init(struct igb_adapter *adapter)
spin_lock_init(&adapter->nfc_lock);
spin_lock_init(&adapter->stats64_lock);
+
+ /* init spinlock to avoid concurrency of VF resources */
+ spin_lock_init(&adapter->vfs_lock);
#ifdef CONFIG_PCI_IOV
switch (hw->mac.type) {
case e1000_82576:
@@ -7958,8 +7965,10 @@ static void igb_rcv_msg_from_vf(struct igb_adapter *adapter, u32 vf)
static void igb_msg_task(struct igb_adapter *adapter)
{
struct e1000_hw *hw = &adapter->hw;
+ unsigned long flags;
u32 vf;
+ spin_lock_irqsave(&adapter->vfs_lock, flags);
for (vf = 0; vf < adapter->vfs_allocated_count; vf++) {
/* process any reset requests */
if (!igb_check_for_rst(hw, vf))
@@ -7973,6 +7982,7 @@ static void igb_msg_task(struct igb_adapter *adapter)
if (!igb_check_for_ack(hw, vf))
igb_rcv_ack_from_vf(adapter, vf);
}
+ spin_unlock_irqrestore(&adapter->vfs_lock, flags);
}
/**
--
2.36.1
