[PATCH 5.15 083/121] iavf: Detach device during reset task

Greg Kroah-Hartman
2022-09-13T14:40:31Z

From: Ivan Vecera <ivecera@redhat.com>

[ Upstream commit aa626da947e9cd30c4cf727493903e1adbb2c0a0 ]

iavf_reset_task() takes crit_lock at the beginning and holds
it during whole call. The function subsequently calls
iavf_init_interrupt_scheme() that grabs RTNL. Problem occurs
when userspace initiates during the reset task any ndo callback
that runs under RTNL like iavf_open() because some of that
functions tries to take crit_lock. This leads to classic A-B B-A
deadlock scenario.

To resolve this situation the device should be detached in
iavf_reset_task() prior taking crit_lock to avoid subsequent
ndos running under RTNL and reattach the device at the end.

Fixes: 62fe2a865e6d ("i40evf: add missing rtnl_lock() around i40evf_set_interrupt_capability")
Cc: Jacob Keller <jacob.e.keller@intel.com>
Cc: Patryk Piotrowski <patryk.piotrowski@intel.com>
Cc: SlawomirX Laba <slawomirx.laba@intel.com>
Tested-by: Vitaly Grinberg <vgrinber@redhat.com>
Signed-off-by: Ivan Vecera <ivecera@redhat.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_main.c | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/intel/iavf/iavf_main.c b/drivers/net/ethernet/intel/iavf/iavf_main.c
index db95786c3419f..00b2ef01f4ea6 100644
--- a/drivers/net/ethernet/intel/iavf/iavf_main.c
+++ b/drivers/net/ethernet/intel/iavf/iavf_main.c
@@ -2222,6 +2222,11 @@ static void iavf_reset_task(struct work_struct *work)
int i = 0, err;
bool running;

+ /* Detach interface to avoid subsequent NDO callbacks */
+ rtnl_lock();
+ netif_device_detach(netdev);
+ rtnl_unlock();
+
/* When device is being removed it doesn't make sense to run the reset
* task, just return in such a case.
*/
@@ -2229,7 +2234,7 @@ static void iavf_reset_task(struct work_struct *work)
if (adapter->state != __IAVF_REMOVE)
queue_work(iavf_wq, &adapter->reset_task);

- return;
+ goto reset_finish;
}

while (!mutex_trylock(&adapter->client_lock))
@@ -2299,7 +2304,6 @@ static void iavf_reset_task(struct work_struct *work)

if (running) {
netif_carrier_off(netdev);
- netif_tx_stop_all_queues(netdev);
adapter->link_up = false;
iavf_napi_disable_all(adapter);
}
@@ -2412,7 +2416,7 @@ static void iavf_reset_task(struct work_struct *work)
mutex_unlock(&adapter->client_lock);
mutex_unlock(&adapter->crit_lock);

- return;
+ goto reset_finish;
reset_err:
if (running) {
set_bit(__IAVF_VSI_DOWN, adapter->vsi.state);
@@ -2423,6 +2427,10 @@ static void iavf_reset_task(struct work_struct *work)
mutex_unlock(&adapter->client_lock);
mutex_unlock(&adapter->crit_lock);
dev_err(&adapter->pdev->dev, "failed to allocate resources during reinit\n");
+reset_finish:
+ rtnl_lock();
+ netif_device_attach(netdev);
+ rtnl_unlock();
}

/**
--
2.35.1