Re: [Regression] mmap with MAP_32BIT randomly fails since 6.1

[Liam R. Howlett]

* Linux regression tracking #adding (Thorsten Leemhuis) <regressions@xxxxxxxxxxxxx> [230303 03:31]:
> [TLDR: I'm adding this report to the list of tracked Linux kernel
> regressions; the text you find below is based on a few templates
> paragraphs you might have encountered already in similar form.
> See link in footer if these mails annoy you.]
> 
> On 02.03.23 16:32, Snild Dolkow wrote:
> > After upgrading a machine from 5.17.4 to 6.1.12 a couple of weeks ago, I
> > started getting (inconsistent) failures when building Android:
> > [...]
> > I have checked a more recent master commit (ee3f96b1, from March 1st),
> > and the problem is still there. Bisecting shows that e15e06a8 is the
> > last good commit, and that 524e00b3 is the first one failing in this
> > way. The 10 or so commits in between run into a page fault BUG down in
> > vma_merge() instead.
> > 
> > This range of commits is about the same as mentioned in
> > https://lore.kernel.org/lkml/0b9f5425-08d4-8013-aa4c-e620c3b10bb2@xxxxxxxxxxxxx/, so I assume that my problem, too, was introduced with the Maple Tree changes. Sending this to the same people and lists.
> > 
> 
> Thanks for the report. To be sure the issue doesn't fall through the
> cracks unnoticed, I'm adding it to regzbot, the Linux kernel regression
> tracking bot:
> 
> #regzbot ^introduced e15e06a8..524e00b3
> #regzbot title mm: mmap with MAP_32BIT randomly fails since 6.1
> #regzbot ignore-activity

Thanks!

> 
> This isn't a regression? This issue or a fix for it are already
> discussed somewhere else? It was fixed already? You want to clarify when
> the regression started to happen? Or point out I got the title or
> something else totally wrong? Then just reply and tell me -- ideally
> while also telling regzbot about it, as explained by the page listed in
> the footer of this mail.

I've sent a patch which has been tested by Snild and does not fully fix
the issue [1].  I am continuing work on this problem.

> 
> Developers: When fixing the issue, remember to add 'Link:' tags pointing
> to the report (the parent of this mail). See page linked in footer for
> details.

Pretty sure I did this part, so maybe the discussion was already picked
up.

1. https://lore.kernel.org/linux-mm/20230303021540.1056603-1-Liam.Howlett@xxxxxxxxxx/

Cheers,
Liam