SELinux RPM scriplet issue annoucement

Miroslav Grepl mgrepl at redhat.com
Mon Jan 20 21:52:09 UTC 2014


On 01/20/2014 06:48 PM, Adam Williamson wrote:
> On Mon, 2014-01-20 at 12:17 -0500, Matthew Miller wrote:
>> On Sun, Jan 19, 2014 at 08:10:29PM +0100, Michael Schwendt wrote:
>>> A simple "yum -y update ; reboot ; Oh, everything seems to work" has not
>>> been enough this time. And it was an update with a screen full of ticket
>>> numbers for the included bug-fixes/changes. It could have broken something
>>> else, too.
>> Once we have a better automation framework in place, we can have tests like:
>> install selinux update, reboot, install (special) test package version 1,
>> update to test package version 2. (In addition to a series of other things
>> that should work with selinux enabled.)
>>
>>
>>> Btw, some other packages are in the same boat. Imagine a graphics driver
>>> update "seems to work" for three testers that are required for a +3 vote
>>> in the updates system, but fails badly for a hundred other users once it
>>> appears in the stable updates repo.
>> That's a little harder, of course.
> So I've read through this thread now. A few notes:
>
> 1) The precise nature of the failure here makes it a tricky issue to
> deal with. We actually already know that this kind of 'delayed action'
> bug is a tricky scenario to deal with, because we already have a whole
> pretty well-known *category* of similar bugs: scriptlet errors
> themselves. As Harald has pointed out, scriptlet errors are very messy
> bugs that our current testing process is very poor at catching.
>
> If anyone's not familiar with the scriptlet error category, see
> https://fedoraproject.org/wiki/Common_F20_bugs#preun-fail .
>
> So while the idea of an SELinux-specific 'update it, then update it
> again' test case seems to make superficial sense, it's not actually an
> SELinux-specific test. We should in fact be doing this for *all*
> updates, or at the least, all updates that include any scriptlets.
>
> However, it's not even that simple, because this is something that makes
> much more sense to test in an automated way than manually - even more so
> than many things. This specific bug was a bit easier to test than the
> scriptlet case, because you just had to update *any other* package after
> updating selinux-policy to see the bug, but it's clearly in the same
> category as the more difficult case, and we should come up with an
> approach that handles them all. What looks like the right approach has
> already been suggested in the FESCo ticket on this: an automated test
> that takes the update, bumps the spec one revision and tries to update.
> So if the update is foo-1.1-2, the test would build a foo-1.1-3 package
> with no other changes, and try updating from 1.1-2 to 1.1-3. Doing this
> manually is of course a PITA and it's really a _very_ clear candidate
> for automation. Such a test would, I believe, have caught the bug.
>
> As posted to FESCo, though, it's still the case that we're working on
> the automation framework at present and the tests come after that. We
> are aiming to have the framework operational for the F21 cycle, AIUI,
> and it may be plausible to implement this test during that cycle. As
> such a test has several very desirable attributes - i.e. it catches bugs
> which:
>
> 1) cause serious problems that are difficult to recover from
> 2) we are currently very bad at catching manually
> 3) would be difficult and onerous to reliably catch manually even with
> improved manual testing procedures
>
> I'd suggest this test should be a high priority for implementation once
> taskotron is operational, perhaps equal in importance to re-implementing
> the current AutoQA tests.
>
> (Harald is probably correct to note that another bug of precisely this
> type might result in 'innocent' updates being 'blamed' for being broken,
> but we'd at least have a clear indication that something was seriously
> boned, and could investigate/clean up manually - the proposed automated
> test wouldn't make anything worse than it currently is).
>
> 1b) Just in case anyone had forgotten, though, we do have the
> infrastructure for creating package-specific test cases that get
> integrated with Bodhi to an extent, even though I don't think that's the
> way to go in this particular case: see
> https://fedoraproject.org/wiki/QA:SOP_package_test_plan_creation .
>
> 2) I already suggested to the SELinux devs on test@ that perhaps
> selinux-policy updates should have a higher autokarma threshold, and
> they agreed this might be a good idea. It would also be possible for
> them to disable autopush for selinux-policy updates and handle pushing
> them manually, based on whatever policy they choose, though of course
> that's more work than using autopush.
>
> 3) Someone noted that big selinux-policy updates are 'scary'. I think to
> be fair to the SELinux devs it's worth noting they push big updates all
> the time,  with a very high success record. This is the first time I can
> recall a bug anywhere near this serious happening with an SELinux update
> to a stable release. AIUI, they have a very sensible policy for stable
> release updates, which is that except in very exceptional cases, updates
> can only make the policy *more liberal*, they cannot make it *tighter*.
> The bug currently under discussion was caused by a change that came in
> inadvertently, not intentionally, and was actually intended for Rawhide.
Yes, this is a problem with new Fedora releases where we have a lot of 
issues every day. But of course I would be more sensible and set higher 
karma for an update which fixes a lot of bugs (which is what I am going 
to do with the next updates).

So I apologize again and thanks everyone for their work on this issue.
>
> 4) The FESCo ticket has an excellent and thoughtful discussion of the
> proposal for a broad 'minimum time in updates-testing' policy to 'fix'
> this problem - https://fedorahosted.org/fesco/ticket/1223#comment:5 -
> and personally I agree with those who have commented on the ticket that
> it is not the way to go.
>
> 5) Finally, my perennial note that the current update feedback system
> (Bodhi 1.0) is nowhere near optimal. I think it's fair to say everyone
> even casually related to the update process in any way is painfully
> aware of this. I think Bodhi 2.0 has been just around the corner for,
> um, three? four? years now - it's difficult to invest in trying to bodge
> up improvements within the straitjacket of Bodhi 1.0's design (a single
> numerical karma value, with only +1 and -1 adjustments being
> 'significant' so far as the tools and policies are concerned) when it
> always seems like a drastically better design (Bodhi 2.0) is going to
> arrive Real Soon Now, but I guess at *some* point we'd have to conclude
> Bodhi 2.0 really isn't arriving Real Soon and go ahead and work with
> what we have. I don't know how to quantify that point, though. All's I
> can do is reiterate that yes, this is a really significant pain point in
> our current processes, the proposed Bodhi 2.0 design would make things
> almost immeasurably better, and plead with anyone reading this who has
> the power to bump up the importance of / resources assigned to Bodhi
> 2.0's development to do so.



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