[PATCH net v3 3/3] net: ti: icss-iep: Fix possible NULL pointer dereference for perout request

[Meghana Malladi]

ICSS IEP driver has flags to check if perout or pps has been enabled
at any given point of time. Whenever there is request to enable or
disable the signal, the driver first checks its enabled or disabled
and acts accordingly.

After bringing the interface down and up, calling PPS/perout enable
doesn't work as the driver believes PPS is already enabled,
(iep->pps_enabled is not cleared during interface bring down)
and driver will just return true even though there is no signal.
Fix this by setting pps and perout flags to false instead of
disabling perout to avoid possible null pointer dereference.

Fixes: 9b115361248d ("net: ti: icssg-prueth: Fix clearing of IEP_CMP_CFG registers during iep_init")
Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Closes: https://lore.kernel.org/all/7b1c7c36-363a-4085-b26c-4f210bee1df6@stanley.mountain/
Signed-off-by: Meghana Malladi <m-malladi@xxxxxx>
---

Changes from v2(v3-v2):
- Add Reported-by tag and link to the bug reported by Dan Carpenter <dan.carpenter@xxxxxxxxxx>
- drop calling icss_iep_perout_enable() for disabling perout and set perout to false instead

 drivers/net/ethernet/ti/icssg/icss_iep.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/ti/icssg/icss_iep.c b/drivers/net/ethernet/ti/icssg/icss_iep.c
index b4a34c57b7b4..b70e4c482d74 100644
--- a/drivers/net/ethernet/ti/icssg/icss_iep.c
+++ b/drivers/net/ethernet/ti/icssg/icss_iep.c
@@ -820,9 +820,9 @@ int icss_iep_exit(struct icss_iep *iep)
 	icss_iep_disable(iep);
 
 	if (iep->pps_enabled)
-		icss_iep_pps_enable(iep, false);
+		iep->pps_enabled = false;
 	else if (iep->perout_enabled)
-		icss_iep_perout_enable(iep, NULL, false);
+		iep->perout_enabled = false;
 
 	return 0;
 }
-- 
2.43.0