In case the PM domain fails to be powered on in genpd_dev_pm_attach(), it returns -EPROBE_DEFER, but keeping the device attached to its PM domain. This leads to problems when the next attempt to attach is re-tried. More precisely, in that situation an -EEXIST error code is returned, because the device already has its PM domain pointer assigned, from the first attempt.
Now, because of the sloppy error handling by the existing callers of dev_pm_domain_attach(), probing is allowed to continue when -EEXIST is returned. However, in such case there are no guarantees that the PM domain is powered on by genpd, which may lead to hangs when buses/drivers tried to access their devices.
Let's fix this behaviour, simply by detaching the device when powering on fails in genpd_dev_pm_attach().
Cc: stable@vger.kernel.org # v4.11+ Signed-off-by: Ulf Hansson ulf.hansson@linaro.org --- drivers/base/power/domain.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c index 1ea0e25..ef6cf3d5 100644 --- a/drivers/base/power/domain.c +++ b/drivers/base/power/domain.c @@ -2246,6 +2246,9 @@ int genpd_dev_pm_attach(struct device *dev) genpd_lock(pd); ret = genpd_power_on(pd, 0); genpd_unlock(pd); + + if (ret) + genpd_remove_device(pd, dev); out: return ret ? -EPROBE_DEFER : 0; }