Hi,

David open an issue with them now.
https://github.com/systemd/systemd/issues/41372

I used AI to generate a fix for it this afternoon and it seems to be working 
but I hold a bit with it to fully verify it. There is memory leak in the 
systemd-udev when a lot of devices are created in a short time.

Daniel

> -----Original Message-----
> From: Richard Purdie <[email protected]>
> Sent: Friday, 27 March 2026 16:41
> To: David Nyström <[email protected]>; Daniel Turull
> <[email protected]>
> Cc: [email protected]; [email protected];
> [email protected]
> Subject: Re: [OE-core] [PATCH 2/2] oeqa: replace runltp with kirk
> 
> On Fri, 2026-03-27 at 13:30 +0100, David Nyström wrote:
> >
> > On Thu, 26 Mar 2026, Daniel Turull via lists.openembedded.org wrote:
> >
> > > Just an update.
> > >
> > > It is taking a bit more time than expected. My original test only
> > > covered the math test suite in ltp to verify the functionality.
> > >
> > > Some of the ltp test are failing with OOM, some related to systemd-
> > > udev. I'll be disabling them now to have a working ltp. Then look at
> > > the underlaying issues.
> > >
> > > So far I have found 4 failing test cases. Using the default config
> > > without any changes with qemux86-64
> > >
> > > min_free_kbytes (mm) (OOM)
> >
> > This seems to be a buggy testcase for automation. Disable until its
> > fixed.
> > Even if the test own memory consumers sets their own OOM-score higher,
> > there are still chances that the OOM-killer kill the wrong things.
> >
> > > pty07 (pty) (OOM)
> > > ptem02 (pty) (OOM)
> >
> > These seem to me to be related to systemd-udevd having unbounded
> > message queue sizes to its udev workers. IMO, this is a systemd-udevd
> > issue.
> > Some other udev implementations starts dropping events.
> >
> > We should have seen this when using runltp as well ?
> >
> > Death spiral: systemd_259.5
> > 1. Test tight loop creating devices floods systemd-udevd's workers
> > unbounded inbox queue(s).
> > - Single core, low mem, and long running udev rules makes the problem
> > worse.
> > 2. systemd-udevd grows to consume all available RAM 3. OOM killer
> > kills everything but systemd-udevd (OOMScoreAdjust=-
> > 1000)
> > 4. Kernel panic: "no killable processes"
> 
> Are the systemd developers aware of this?
> 
> You're correct that the ltp testing as currently run does sometimes seem to 
> have
> issues and not all tests pass. It is something we've been wanting to look 
> into and
> resolve but simply haven't had time.
> 
> Finding an issue like the systemd one does hint that there may be value in 
> some of
> the testing.
> 
> Ideally we'd identify and disable the problematic tests, then we would know 
> any
> failures were new and potential issues. The new version of the patch series 
> from
> Daniel does move us forward with that, thanks!
> 
> Cheers,
> 
> Richard
> 
> 
> 

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