On Mon, May 17, 2021 at 11:27:38AM +0200, Robert Foss wrote:
Hey Yu,
On Mon, 17 May 2021 at 10:08, Yu Kuai yukuai3@huawei.com wrote:
pm_runtime_get_sync will increment pm usage counter even it failed. Forgetting to putting operation will result in reference leak here. Fix it by replacing it with pm_runtime_resume_and_get to keep usage counter balanced.
Reported-by: Hulk Robot hulkci@huawei.com Signed-off-by: Yu Kuai yukuai3@huawei.com
drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c index 0cd8f40fb690..305489d48c16 100644 --- a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c +++ b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c @@ -2478,7 +2478,7 @@ static int cdns_mhdp_probe(struct platform_device *pdev) clk_prepare_enable(clk);
pm_runtime_enable(dev);
ret = pm_runtime_get_sync(dev);
ret = pm_runtime_resume_and_get(dev); if (ret < 0) { dev_err(dev, "pm_runtime_get_sync failed\n"); pm_runtime_disable(dev);The code is correct as it is. If pm_runtime_get_sync() fails and increments[1] the pm.usage_count variable, that isn't a problem since pm_runtime_disable() disables pm, and resets pm.usage_count variable to zero[2].
No it doesn't; pm_runtime_disable() does not reset the counter and you still need to decrement the usage count when pm_runtime_get_sync() fails.
[1] https://elixir.bootlin.com/linux/latest/source/include/linux/pm_runtime.h#L3... [2] https://elixir.bootlin.com/linux/latest/source/drivers/base/power/runtime.c#...
Johan