WARNING: suspicious RCU usage

[Fabio Estevam]

Hi Paul,

On Tue, Dec 12, 2017 at 5:36 PM, Paul E. McKenney
<paulmck at linux.vnet.ibm.com> wrote:

>> Ok, just tested with CONFIG_BL_SWITCHER=y on a imx6q-cubox-i:
>
> Just to confirm, your dmesg below is illustrating the hang, correct?

Sorry for not being clear. Let me clarify my tests.

If I run a mainline kernel on a imx6q I do see the exact same RCU
warning as reported by Peng Fan in this thread.

This is 100% reproducible: the first time I do a suspend/resume after
boot the RCU warning is present. Subsequent suspend/resume cycles do
not show the warning.

With your patch applied I don't see the RCU warning anymore.

I originally tested the standard imx_v6_v7_defconfig and also a kernel
with CONFIG_BL_SWITCHER=y as suggested by Russell.

In my tests even with CONFIG_BL_SWITCHER=y suspend/resume works fine
and no more RCU warnings were seen.

The dmesg I shared shows the normal output without the RCU warning.

Thanks