linux-kernel - Re: Linux 5.0-rc2 seccomp_bpf user_notification

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Date:   Thu, 17 Jan 2019 10:53:22 -0700
From:   shuah <shuah@...nel.org>
To:     Tycho Andersen <tycho@...ho.ws>, Kees Cook <keescook@...omium.org>
Cc:     James Morris <jmorris@...ei.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        "open list:KERNEL SELFTEST FRAMEWORK" 
        <linux-kselftest@...r.kernel.org>, shuah <shuah@...nel.org>
Subject: Re: Linux 5.0-rc2 seccomp_bpf user_notification_basic test hangs

On 1/17/19 9:45 AM, Tycho Andersen wrote:
> On Thu, Jan 17, 2019 at 08:41:59AM -0800, Kees Cook wrote:
>> On Thu, Jan 17, 2019 at 8:27 AM Tycho Andersen <tycho@...ho.ws> wrote:
>>>
>>> On Thu, Jan 17, 2019 at 08:12:50AM -0800, Kees Cook wrote:
>>>> On Wed, Jan 16, 2019 at 5:26 PM shuah <shuah@...nel.org> wrote:
>>>>> I am running Linux 5.0-rc2 and not an older kernel.
>>>>
>>>> Weird. I couldn't reproduce this on 5.0-rc2, but I did see it on a
>>>> kernel without seccomp user_notif. Does the patch I sent fix it for
>>>> you? (And if so, can you take it in your tree?)
>>>
>>> I can reproduce it; you have to run it as non-root. I think your patch
>>> is necessary to get it to at least fail. The question is: what should
>>> we do about these tests that require real root? Skip them if we're not
>>> real-root, I guess?
>>
>> Hm, maybe use the XFAIL() bit of the harness?
>>
>> Perhaps it's time to make it a root-only test and do internal
>> priv-dropping to test the nnp-requiring parts? I'll add it to the TODO
>> list...
> 

Yup that is a good way to handle it. Please skip the test with ksft skip
code for non-root runs.

> Ok, I'll try to send a couple of patches soon to fix some of this up.
> But at least yours should should stop things from hanging for now.
> 

I am going to take Kees's patch to prevent hangs right away.

thanks,
-- Shuah