[PATCH 4.20 097/171] usb: dwc3: exynos: Fix error handling of clk_prepare_enable

[Greg Kroah-Hartman]

4.20-stable review patch.  If anyone has any objections, please let me know.

------------------

[ Upstream commit 512e6fb589bc18f9321457632e89b95017447db9 ]

If clk_prepare_enable() fails in dwc3_exynos_probe() or in
dwc3_exynos_resume(), exynos->clks[0] is left undisabled
because of usage preincrement in while condition.

Found by Linux Driver Verification project (linuxtesting.org).

Fixes: 9f2168367a0a ("usb: dwc3: exynos: Rework clock handling and prepare for new variants")
Acked-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
Signed-off-by: Alexey Khoroshilov <khoroshilov@xxxxxxxxx>
Signed-off-by: Felipe Balbi <felipe.balbi@xxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/usb/dwc3/dwc3-exynos.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/dwc3/dwc3-exynos.c b/drivers/usb/dwc3/dwc3-exynos.c
index cb7fcd7c0ad8..c1e9ea621f41 100644
--- a/drivers/usb/dwc3/dwc3-exynos.c
+++ b/drivers/usb/dwc3/dwc3-exynos.c
@@ -78,7 +78,7 @@ static int dwc3_exynos_probe(struct platform_device *pdev)
 	for (i = 0; i < exynos->num_clks; i++) {
 		ret = clk_prepare_enable(exynos->clks[i]);
 		if (ret) {
-			while (--i > 0)
+			while (i-- > 0)
 				clk_disable_unprepare(exynos->clks[i]);
 			return ret;
 		}
@@ -223,7 +223,7 @@ static int dwc3_exynos_resume(struct device *dev)
 	for (i = 0; i < exynos->num_clks; i++) {
 		ret = clk_prepare_enable(exynos->clks[i]);
 		if (ret) {
-			while (--i > 0)
+			while (i-- > 0)
 				clk_disable_unprepare(exynos->clks[i]);
 			return ret;
 		}
-- 
2.19.1