[PATCH AUTOSEL 5.8 109/132] drivers: watchdog: rdc321x_wdt: Fix race condition bugs

Sasha Levin
2020-10-26T23:58:00Z

From: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>

[ Upstream commit 4b2e7f99cdd314263c9d172bc17193b8b6bba463 ]

In rdc321x_wdt_probe(), rdc321x_wdt_device.queue is initialized
after misc_register(), hence if ioctl is called before its
initialization which can call rdc321x_wdt_start() function,
it will see an uninitialized value of rdc321x_wdt_device.queue,
hence initialize it before misc_register().
Also, rdc321x_wdt_device.default_ticks is accessed in reset()
function called from write callback, thus initialize it before
misc_register().

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

Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20200807112902.28764-1-madhuparnabhowmik10@gmail.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/watchdog/rdc321x_wdt.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/watchdog/rdc321x_wdt.c b/drivers/watchdog/rdc321x_wdt.c
index 57187efeb86f1..f0c94ea51c3e4 100644
--- a/drivers/watchdog/rdc321x_wdt.c
+++ b/drivers/watchdog/rdc321x_wdt.c
@@ -231,6 +231,8 @@ static int rdc321x_wdt_probe(struct platform_device *pdev)

rdc321x_wdt_device.sb_pdev = pdata->sb_pdev;
rdc321x_wdt_device.base_reg = r->start;
+ rdc321x_wdt_device.queue = 0;
+ rdc321x_wdt_device.default_ticks = ticks;

err = misc_register(&rdc321x_wdt_misc);
if (err < 0) {
@@ -245,14 +247,11 @@ static int rdc321x_wdt_probe(struct platform_device *pdev)
rdc321x_wdt_device.base_reg, RDC_WDT_RST);

init_completion(&rdc321x_wdt_device.stop);
- rdc321x_wdt_device.queue = 0;

clear_bit(0, &rdc321x_wdt_device.inuse);

timer_setup(&rdc321x_wdt_device.timer, rdc321x_wdt_trigger, 0);

- rdc321x_wdt_device.default_ticks = ticks;
-
dev_info(&pdev->dev, "watchdog init success\n");

return 0;
--
2.25.1