[PATCH 5.9 027/105] can: c_can: c_can_power_up(): fix error handling

From: Greg Kroah-Hartman
Date: Mon Dec 14 2020 - 13:50:59 EST


From: Zhang Qilong <zhangqilong3@xxxxxxxxxx>

[ Upstream commit 44cef0c0ffbd8d61143712ce874be68a273b7884 ]

In the error handling in c_can_power_up(), there are two bugs:

1) c_can_pm_runtime_get_sync() will increase usage counter if device is not
empty. Forgetting to call c_can_pm_runtime_put_sync() will result in a
reference leak here.

2) c_can_reset_ram() operation will set start bit when enable is true. We
should clear it in the error handling.

We fix it by adding c_can_pm_runtime_put_sync() for 1), and
c_can_reset_ram(enable is false) for 2) in the error handling.

Fixes: 8212003260c60 ("can: c_can: Add d_can suspend resume support")
Fixes: 52cde85acc23f ("can: c_can: Add d_can raminit support")
Signed-off-by: Zhang Qilong <zhangqilong3@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20201128133922.3276973-2-zhangqilong3@xxxxxxxxxx
[mkl: return "0" instead of "ret"]
Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/net/can/c_can/c_can.c | 18 ++++++++++++++----
1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/drivers/net/can/c_can/c_can.c b/drivers/net/can/c_can/c_can.c
index 8e9f5620c9a21..095505fa09de3 100644
--- a/drivers/net/can/c_can/c_can.c
+++ b/drivers/net/can/c_can/c_can.c
@@ -1304,12 +1304,22 @@ int c_can_power_up(struct net_device *dev)
time_after(time_out, jiffies))
cpu_relax();

- if (time_after(jiffies, time_out))
- return -ETIMEDOUT;
+ if (time_after(jiffies, time_out)) {
+ ret = -ETIMEDOUT;
+ goto err_out;
+ }

ret = c_can_start(dev);
- if (!ret)
- c_can_irq_control(priv, true);
+ if (ret)
+ goto err_out;
+
+ c_can_irq_control(priv, true);
+
+ return 0;
+
+err_out:
+ c_can_reset_ram(priv, false);
+ c_can_pm_runtime_put_sync(priv);

return ret;
}
--
2.27.0