PM: domains: Ensure genpd_debugfs_dir exists before remove

Both genpd_debug_add() and genpd_debug_remove() may be called
indirectly by other drivers while genpd_debugfs_dir is not yet
set. For example, drivers can call pm_genpd_init() in probe or
pm_genpd_init() in probe fail/cleanup path:

pm_genpd_init()
 --> genpd_debug_add()

pm_genpd_remove()
 --> genpd_remove()
   --> genpd_debug_remove()

At this time, genpd_debug_init() may not yet be called.

genpd_debug_add() checks that if genpd_debugfs_dir is NULL, it
will return directly. Make sure this is also checked
in pm_genpd_remove(), otherwise components under debugfs root
which has the same name as other components under pm_genpd may
be accidentally removed, since NULL represents debugfs root.

Fixes: 718072ceb211 ("PM: domains: create debugfs nodes when adding power domains")
Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index 739e52c..55a10e6 100644 (file)
--- 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);
 }