Mailinglist Archive: opensuse-bugs (4644 mails)

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[Bug 1045340] regression: java segfaults on latest kernels caused by the stack gap fix
  • From: bugzilla_noreply@xxxxxxxxxx
  • Date: Thu, 22 Jun 2017 16:06:11 +0000
  • Message-id: <>

--- Comment #24 from Michal Hocko <mhocko@xxxxxxxx> ---
(In reply to Marcus Meissner from comment #22)
Created attachment 729855 [details]

From: Solar Designer <solar@xxxxxxxxxxxx>

Dear Alexander,
probably it is already known,
otherwise please share it in oss-security@
I've noticed the problem on Red Hat kernels first, and reported to Red Hat
but now I've found the same problem on Ubuntu kernels.
It does not affect mainline patch "mm: larger stack guard gap, between vmas"
but seems distributors have used some other incorrect patch (shared in
linux-distros@ ??? )

Description of problem:
mmap(MAP_GROUWSDOWN) works incorrectly on Red Hat and Ubuntu kernels with
stackguard fix.

We have application that creates stack by using MAP_GROUWSDOWN , provide
this area into clone(),
where it fails on access to mapped area.

This is a different problem unrelated to this bug. In fact I would argue that
we have never supported/implemented MAP_GROUWSDOWN correctly. There is only one
stack that can work reliably because we place it above any mmaps or grow mmaps
from lower addresses. A larger gap just makes it more obvious.

Feel free to open a separate bug for this but I would tend to close it as

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