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Subject[PATCH 5.16 153/186] iavf: Fix locking for VIRTCHNL_OP_GET_OFFLOAD_VLAN_V2_CAPS
Date
From: Slawomir Laba <slawomirx.laba@intel.com>

[ Upstream commit 0579fafd37fb7efe091f0e6c8ccf968864f40f3e ]

iavf_virtchnl_completion is called under crit_lock but when
the code for VIRTCHNL_OP_GET_OFFLOAD_VLAN_V2_CAPS is called,
this lock is released in order to obtain rtnl_lock to avoid
ABBA deadlock with unregister_netdev.

Along with the new way iavf_remove behaves, there exist
many risks related to the lock release and attmepts to regrab
it. The driver faces crashes related to races between
unregister_netdev and netdev_update_features. Yet another
risk is that the driver could already obtain the crit_lock
in order to destroy it and iavf_virtchnl_completion could
crash or block forever.

Make iavf_virtchnl_completion never relock crit_lock in it's
call paths.

Extract rtnl_lock locking logic to the driver for
unregister_netdev in order to set the netdev_registered flag
inside the lock.

Introduce a new flag that will inform adminq_task to perform
the code from VIRTCHNL_OP_GET_OFFLOAD_VLAN_V2_CAPS right after
it finishes processing messages. Guard this code with remove
flags so it's never called when the driver is in remove state.

Fixes: 5951a2b9812d ("iavf: Fix VLAN feature flags after VFR")
Signed-off-by: Slawomir Laba <slawomirx.laba@intel.com>
Signed-off-by: Phani Burra <phani.r.burra@intel.com>
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Mateusz Palczewski <mateusz.palczewski@intel.com>
Tested-by: Konrad Jankowski <konrad0.jankowski@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/ethernet/intel/iavf/iavf.h | 1 +
drivers/net/ethernet/intel/iavf/iavf_main.c | 16 +++++++++++++++-
drivers/net/ethernet/intel/iavf/iavf_virtchnl.c | 14 +-------------
3 files changed, 17 insertions(+), 14 deletions(-)

diff --git a/drivers/net/ethernet/intel/iavf/iavf.h b/drivers/net/ethernet/intel/iavf/iavf.h
index ffc61993019b..9a122aea6979 100644
--- a/drivers/net/ethernet/intel/iavf/iavf.h
+++ b/drivers/net/ethernet/intel/iavf/iavf.h
@@ -274,6 +274,7 @@ struct iavf_adapter {
#define IAVF_FLAG_LEGACY_RX BIT(15)
#define IAVF_FLAG_REINIT_ITR_NEEDED BIT(16)
#define IAVF_FLAG_QUEUES_DISABLED BIT(17)
+#define IAVF_FLAG_SETUP_NETDEV_FEATURES BIT(18)
/* duplicates for common code */
#define IAVF_FLAG_DCB_ENABLED 0
/* flags for admin queue service task */
diff --git a/drivers/net/ethernet/intel/iavf/iavf_main.c b/drivers/net/ethernet/intel/iavf/iavf_main.c
index 2a9044c8396f..1af3fe427543 100644
--- a/drivers/net/ethernet/intel/iavf/iavf_main.c
+++ b/drivers/net/ethernet/intel/iavf/iavf_main.c
@@ -2465,6 +2465,18 @@ static void iavf_adminq_task(struct work_struct *work)
} while (pending);
mutex_unlock(&adapter->crit_lock);

+ if ((adapter->flags & IAVF_FLAG_SETUP_NETDEV_FEATURES)) {
+ if (adapter->netdev_registered ||
+ !test_bit(__IAVF_IN_REMOVE_TASK, &adapter->crit_section)) {
+ struct net_device *netdev = adapter->netdev;
+
+ rtnl_lock();
+ netdev_update_features(netdev);
+ rtnl_unlock();
+ }
+
+ adapter->flags &= ~IAVF_FLAG_SETUP_NETDEV_FEATURES;
+ }
if ((adapter->flags &
(IAVF_FLAG_RESET_PENDING | IAVF_FLAG_RESET_NEEDED)) ||
adapter->state == __IAVF_RESETTING)
@@ -4029,8 +4041,10 @@ static void iavf_remove(struct pci_dev *pdev)
cancel_delayed_work_sync(&adapter->watchdog_task);

if (adapter->netdev_registered) {
- unregister_netdev(netdev);
+ rtnl_lock();
+ unregister_netdevice(netdev);
adapter->netdev_registered = false;
+ rtnl_unlock();
}
if (CLIENT_ALLOWED(adapter)) {
err = iavf_lan_del_device(adapter);
diff --git a/drivers/net/ethernet/intel/iavf/iavf_virtchnl.c b/drivers/net/ethernet/intel/iavf/iavf_virtchnl.c
index d60bf7c21200..d3da65d24bd6 100644
--- a/drivers/net/ethernet/intel/iavf/iavf_virtchnl.c
+++ b/drivers/net/ethernet/intel/iavf/iavf_virtchnl.c
@@ -1752,19 +1752,7 @@ void iavf_virtchnl_completion(struct iavf_adapter *adapter,

spin_unlock_bh(&adapter->mac_vlan_list_lock);
iavf_process_config(adapter);
-
- /* unlock crit_lock before acquiring rtnl_lock as other
- * processes holding rtnl_lock could be waiting for the same
- * crit_lock
- */
- mutex_unlock(&adapter->crit_lock);
- rtnl_lock();
- netdev_update_features(adapter->netdev);
- rtnl_unlock();
- if (iavf_lock_timeout(&adapter->crit_lock, 10000))
- dev_warn(&adapter->pdev->dev, "failed to acquire crit_lock in %s\n",
- __FUNCTION__);
-
+ adapter->flags |= IAVF_FLAG_SETUP_NETDEV_FEATURES;
}
break;
case VIRTCHNL_OP_ENABLE_QUEUES:
--
2.34.1


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