of_overlay_destroy() can return `-ENODEV' error code once it
failed to find the requested overlay in `ov_idr'. However,
of_unittest_destroy_tracked_overlays() does not handle this
error code correctly and continues to call of_overlay_destroy()
on the 'missing' overlay over and over again. This results in
a printk flood
[..]
[ 33.497583] of_overlay_destroy: Could not find overlay #6
[ 33.497583] of_overlay_destroy: Could not find overlay #6
[ 33.497584] ### dt-test ### of_unittest_destroy_tracked_overlays: overlay destroy failed for #6
[ 33.497584] ### dt-test ### of_unittest_destroy_tracked_overlays: overlay destroy failed for #6
[ 33.497586] of_overlay_destroy: Could not find overlay #6
[ 33.497586] of_overlay_destroy: Could not find overlay #6
[ 33.497587] ### dt-test ### of_unittest_destroy_tracked_overlays: overlay destroy failed for #6
[ 33.497587] ### dt-test ### of_unittest_destroy_tracked_overlays: overlay destroy failed for #6
[..]
which is not really good due to printk design, and can lead to soft
lockups, hard lockups, etc. (depending on the context console_unlock()
is being called from). The problem has bee observed in real life
and reported by Ying Huang.
This patch does not address the root cause of missing overlay in
`ov_idr', it fixes the endless loop only.
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
Reported-by: kernel test robot <ying.huang@xxxxxxxxxxxxxxx>
Link: lkml.kernel.org/r/87fuwk1c0o.fsf@xxxxxxxxxxxxxxxxxxxx
---
drivers/of/unittest.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/drivers/of/unittest.c b/drivers/of/unittest.c
index 979b6e4..e986e6e 100644
--- a/drivers/of/unittest.c
+++ b/drivers/of/unittest.c
@@ -1165,6 +1165,11 @@ static void of_unittest_destroy_tracked_overlays(void)
continue;
ret = of_overlay_destroy(id + overlay_first_id);
+ if (ret == -ENODEV) {
+ pr_warn("%s: no overlay to destroy for #%d\n",
+ __func__, id + overlay_first_id);
+ continue;
+ }
if (ret != 0) {
defers++;
pr_warn("%s: overlay destroy failed for #%d\n",
--
2.8.0.rc0
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