[dpdk-dev] [PATCH] net/axgbe: fix double unlock coverity issue

[Pallantla Poornima <pallantlax.poornima@intel.com>]

One issue caught by Coverity 340835
*unlock: axgbe_phy_set_mode unlocks pdata->phy_mutex
*double_unlock: axgbe_phy_sfp_detect unlocks pdata->phy_mutex
while it is unlocked.

In axgbe_phy_sfp_detect()/axgbe_phy_set_redrv_mode(),
axgbe_phy_get_comm_ownership() and axgbe_phy_put_comm_ownership()
are invoked subsequently.

Currently in axgbe_phy_get_comm_ownership(), during one of the case
'phy_data->comm_owned' is not protected and before returning 0,
lock is not called and unlock is called in axgbe_phy_put_comm_ownership()
directly which is incorrect.

Ideally, the variable 'phy_data->comm_owned' needs to be protected.
During success scenario, lock is called in axgbe_phy_get_comm_ownership()
followed by unlock in axgbe_phy_put_comm_ownership().
In failure case, unlock is invoked in axgbe_phy_get_comm_ownership()
itself appropriately.

The fix is to protect 'phy_data->comm_owned' in the identified case
ensuring locks/unlocks properly exist.

Coverity issue: 340835
Fixes: a5c7273771 ("net/axgbe: add phy programming APIs")
Cc: stable@dpdk.org

Signed-off-by: Pallantla Poornima <pallantlax.poornima@intel.com>
---
 drivers/net/axgbe/axgbe_phy_impl.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/net/axgbe/axgbe_phy_impl.c b/drivers/net/axgbe/axgbe_phy_impl.c
index 973177f69..2267c5f81 100644
--- a/drivers/net/axgbe/axgbe_phy_impl.c
+++ b/drivers/net/axgbe/axgbe_phy_impl.c
@@ -412,15 +412,15 @@ static int axgbe_phy_get_comm_ownership(struct axgbe_port *pdata)
 	uint64_t timeout;
 	unsigned int mutex_id;
 
-	if (phy_data->comm_owned)
-		return 0;
-
 	/* The I2C and MDIO/GPIO bus is multiplexed between multiple devices,
 	 * the driver needs to take the software mutex and then the hardware
 	 * mutexes before being able to use the busses.
 	 */
 	pthread_mutex_lock(&pdata->phy_mutex);
 
+	if (phy_data->comm_owned)
+		return 0;
+
 	/* Clear the mutexes */
 	XP_IOWRITE(pdata, XP_I2C_MUTEX, AXGBE_MUTEX_RELEASE);
 	XP_IOWRITE(pdata, XP_MDIO_MUTEX, AXGBE_MUTEX_RELEASE);
-- 
2.17.2