[PATCH 5.4 018/108] cxgb4: fix IRQ free race during driver unload

Greg Kroah-Hartman
2021-07-26T16:06:00Z

From: Shahjada Abul Husain <shahjada@chelsio.com>

[ Upstream commit 015fe6fd29c4b9ac0f61b8c4455ef88e6018b9cc ]

IRQs are requested during driver's ndo_open() and then later
freed up in disable_interrupts() during driver unload.
A race exists where driver can set the CXGB4_FULL_INIT_DONE
flag in ndo_open() after the disable_interrupts() in driver
unload path checks it, and hence misses calling free_irq().

Fix by unregistering netdevice first and sync with driver's
ndo_open(). This ensures disable_interrupts() checks the flag
correctly and frees up the IRQs properly.

Fixes: b37987e8db5f ("cxgb4: Disable interrupts and napi before unregistering netdev")
Signed-off-by: Shahjada Abul Husain <shahjada@chelsio.com>
Signed-off-by: Raju Rangoju <rajur@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
.../net/ethernet/chelsio/cxgb4/cxgb4_main.c | 18 ++++++++++--------
drivers/net/ethernet/chelsio/cxgb4/cxgb4_uld.c | 3 +++
2 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c
index deb1c1f30107..21414a34a5b5 100644
--- a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c
+++ b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c
@@ -2245,6 +2245,9 @@ static void detach_ulds(struct adapter *adap)
{
unsigned int i;

+ if (!is_uld(adap))
+ return;
+
mutex_lock(&uld_mutex);
list_del(&adap->list_node);

@@ -6152,10 +6155,13 @@ static void remove_one(struct pci_dev *pdev)
*/
destroy_workqueue(adapter->workq);

- if (is_uld(adapter)) {
- detach_ulds(adapter);
- t4_uld_clean_up(adapter);
- }
+ detach_ulds(adapter);
+
+ for_each_port(adapter, i)
+ if (adapter->port[i]->reg_state == NETREG_REGISTERED)
+ unregister_netdev(adapter->port[i]);
+
+ t4_uld_clean_up(adapter);

adap_free_hma_mem(adapter);

@@ -6163,10 +6169,6 @@ static void remove_one(struct pci_dev *pdev)

cxgb4_free_mps_ref_entries(adapter);

- for_each_port(adapter, i)
- if (adapter->port[i]->reg_state == NETREG_REGISTERED)
- unregister_netdev(adapter->port[i]);
-
debugfs_remove_recursive(adapter->debugfs_root);

if (!is_t4(adapter->params.chip))
diff --git a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_uld.c b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_uld.c
index 86b528d8364c..971bdd70b6d6 100644
--- a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_uld.c
+++ b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_uld.c
@@ -638,6 +638,9 @@ void t4_uld_clean_up(struct adapter *adap)
{
unsigned int i;

+ if (!is_uld(adap))
+ return;
+
mutex_lock(&uld_mutex);
for (i = 0; i < CXGB4_ULD_MAX; i++) {
if (!adap->uld[i].handle)
--
2.30.2