[PATCH] PM: domains: Ensure genpd_debugfs_dir exists before remove

[Hsin-Yi Wang <hsinyi@chromium.org>]

genpd_debug_remove() may be indirectly called from others while
genpd_debugfs_dir is not yet set. Make sure genpd_debugfs_dir exists
before remove the sub components, otherwise components under
/sys/kernel/debug may be accidentally removed.

Fixes: 718072ceb211 ("PM: domains: create debugfs nodes when adding power domains")
Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org>
---
An example:
scpsys_probe() in drivers/soc/mediatek/mtk-pm-domains.c indirectly calls
genpd_debug_remove() on probe fail, causing /sys/kernel/debug/usb to be
removed.
---
 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 3e86772d5fac5..5a2e0232862e0 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -222,6 +222,9 @@ static void genpd_debug_remove(struct generic_pm_domain *genpd)
 {
 	struct dentry *d;
 
+	if (!genpd_debugfs_dir)
+		return;
+
 	d = debugfs_lookup(genpd->name, genpd_debugfs_dir);
 	debugfs_remove(d);
 }
-- 
2.37.0.rc0.161.g10f37bed90-goog