Re: [REGRESSION] XArray commit prevents booting with 6.0-rc1 or later

[Jorropo]

Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote :
>
> On Sat, Nov 19, 2022 at 05:07:45AM +0100, Jorropo wrote:
> > #regzbot introduced v5.19-rc6..1dd685c414a7b9fdb3d23aca3aedae84f0b998ae
> >
> > Hi, I recently tried to upgrade to linux v6.0.x but when trying to
> > boot it fails with "error: out of memory" when or after loading
> > initramfs (which then kpanics because the vfs root is missing).
> > The latest releases I tested are v6.0.9 and v6.1-rc5 and it's broken there too.
> >
> > I bisected the error to this patch:
> > 1dd685c414a7b9fdb3d23aca3aedae84f0b998ae "XArray: Add calls to
> > might_alloc()" is the first bad commit.
> > I've confirmed this is not a side effect of a poor bitsect because
> > 1dd685c414a7b9fdb3d23aca3aedae84f0b998ae~1 (v5.19-rc6) works.
>
> That makes no sense.  I can't look into this until Wednesday, but I
> suggest that what you have is an intermittent failure to boot, and
> the bisect has led you down the wrong path.

I rebuilt both 1dd685c414a7b9fdb3d23aca3aedae84f0b998ae and
the parent commit (v5.19-rc6), then tried to start each one 8 times
(shuffled in a Thue morse sequence).
0 successes for 1dd685c414a7b9fdb3d23aca3aedae84f0b998ae
8 successes for v5.19-rc6

This really does not look like an intermittent issue.