Re: [PATCH 4.9 00/25] 4.9.316-rc1 review

Jon Hunter
2022-05-24T14:56:42Z

On 24/05/2022 13:09, Greg Kroah-Hartman wrote:

...

>> I am seeing a boot regression on tegra124-jetson-tk1 and reverting the above
>> commit is fixing the problem. This also appears to impact linux-4.14.y,
>> 4.19.y and 5.4.y.
>>
>> Test results for stable-v4.9:
>> 8 builds: 8 pass, 0 fail
>> 18 boots: 16 pass, 2 fail
>> 18 tests: 18 pass, 0 fail
>>
>> Linux version: 4.9.316-rc1-gbe4ec3e3faa1
>> Boards tested: tegra124-jetson-tk1, tegra20-ventana,
>> tegra210-p2371-2180, tegra30-cardhu-a04
>>
>> Boot failures: tegra124-jetson-tk1
>
> Odd. This is also in 5.10.y, right? No issues there? Are we missing
> something?

Actually, the more I look at this, the more I see various intermittent
reports with this and it is also impacting the mainline.

The problem is that the commit in question is causing a ton of messages
to be printed a boot and this sometimes is causing the boot test to fail
because the boot is taking too long. The console shows ...

[ 1233.327547] CPU0: Spectre BHB: using loop workaround
[ 1233.327795] CPU1: Spectre BHB: using loop workaround
[ 1233.328270] CPU1: Spectre BHB: using loop workaround
[ 1233.328700] CPU1: Spectre BHB: using loop workaround
[ 1233.355477] CPU2: Spectre BHB: using loop workaround
** 7 printk messages dropped **
[ 1233.366271] CPU0: Spectre BHB: using loop workaround
[ 1233.366580] CPU0: Spectre BHB: using loop workaround
[ 1233.366815] CPU1: Spectre BHB: using loop workaround
[ 1233.405475] CPU1: Spectre BHB: using loop workaround
[ 1233.405874] CPU0: Spectre BHB: using loop workaround
[ 1233.406041] CPU1: Spectre BHB: using loop workaround
** 1 printk messages dropped **

There is a similar report of this [0] and I believe that we need a
similar fix for the above prints as well. I have reported this to Ard
[1]. So I am not sure that these Spectre BHB patches are quite ready for
stable.

Cheers
Jon

[0]
https://lore.kernel.org/linux-arm-kernel/20220519161310.1489625-1-dmitry.osipenko@collabora.com/T/
[1]
https://lore.kernel.org/linux-arm-kernel/a589f56d-a0e1-328d-e4be-9427342d46b8@nvidia.com/

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nvpublic