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| Started by | Sergey Senozhatsky <sergey.senozhatsky@gmail.com> |
|---|---|
| First post | 2016-03-02 12:30 +0100 |
| Last post | 2016-03-04 00:00 +0100 |
| Articles | 3 — 3 participants |
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[PATCH] of/unittest: fix infinite loop in of_unittest_destroy_tracked_overlays() Sergey Senozhatsky <sergey.senozhatsky@gmail.com> - 2016-03-02 12:30 +0100
Re: [PATCH] of/unittest: fix infinite loop in of_unittest_destroy_tracked_overlays() Petr Mladek <pmladek@suse.com> - 2016-03-02 15:50 +0100
Re: [PATCH] of/unittest: fix infinite loop in of_unittest_destroy_tracked_overlays() Rob Herring <robh@kernel.org> - 2016-03-04 00:00 +0100
| From | Sergey Senozhatsky <sergey.senozhatsky@gmail.com> |
|---|---|
| Date | 2016-03-02 12:30 +0100 |
| Subject | [PATCH] of/unittest: fix infinite loop in of_unittest_destroy_tracked_overlays() |
| Message-ID | <r8d8D-6UP-27@gated-at.bofh.it> |
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@gmail.com>
Reported-by: kernel test robot <ying.huang@linux.intel.com>
Link: lkml.kernel.org/r/87fuwk1c0o.fsf@yhuang-dev.intel.com
---
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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| From | Petr Mladek <pmladek@suse.com> |
|---|---|
| Date | 2016-03-02 15:50 +0100 |
| Subject | Re: [PATCH] of/unittest: fix infinite loop in of_unittest_destroy_tracked_overlays() |
| Message-ID | <r8gga-yT-19@gated-at.bofh.it> |
| In reply to | #1347971 |
On Wed 2016-03-02 20:24:49, Sergey Senozhatsky wrote: > 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@gmail.com> > Reported-by: kernel test robot <ying.huang@linux.intel.com> > Link: lkml.kernel.org/r/87fuwk1c0o.fsf@yhuang-dev.intel.com I am not sure why the overlay did not exist but this patch avoids a possible infinite loop and makes sense on its own. Reviewed-by: Petr Mladek <pmladek@suse.com> Best Regards, Petr
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| From | Rob Herring <robh@kernel.org> |
|---|---|
| Date | 2016-03-04 00:00 +0100 |
| Subject | Re: [PATCH] of/unittest: fix infinite loop in of_unittest_destroy_tracked_overlays() |
| Message-ID | <r8KnU-5IL-11@gated-at.bofh.it> |
| In reply to | #1347971 |
On Wed, Mar 02, 2016 at 08:24:49PM +0900, Sergey Senozhatsky wrote: > 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@gmail.com> > Reported-by: kernel test robot <ying.huang@linux.intel.com> > Link: lkml.kernel.org/r/87fuwk1c0o.fsf@yhuang-dev.intel.com > --- > drivers/of/unittest.c | 5 +++++ > 1 file changed, 5 insertions(+) Applied, thanks. Rob
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