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Groups > linux.kernel > #1681808
| From | Andrew Morton <akpm@linux-foundation.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH] mm: mm, mmap: do not blow on PROT_NONE MAP_FIXED holes in the stack |
| Date | 2017-07-05 23:20 +0200 |
| Message-ID | <tZZSh-3hk-5@gated-at.bofh.it> (permalink) |
| References | <tZVOF-nA-3@gated-at.bofh.it> <tZWB4-Ve-19@gated-at.bofh.it> <tZXdM-1mP-15@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Wed, 5 Jul 2017 20:28:49 +0200 Michal Hocko <mhocko@kernel.org> wrote:
> "mm: enlarge stack guard gap" has introduced a regression in some rust
> and Java environments which are trying to implement their own stack
> guard page. They are punching a new MAP_FIXED mapping inside the
> existing stack Vma.
>
> This will confuse expand_{downwards,upwards} into thinking that the stack
> expansion would in fact get us too close to an existing non-stack vma
> which is a correct behavior wrt. safety. It is a real regression on
> the other hand. Let's work around the problem by considering PROT_NONE
> mapping as a part of the stack. This is a gros hack but overflowing to
> such a mapping would trap anyway an we only can hope that usespace
> knows what it is doing and handle it propely.
>
> Fixes: d4d2d35e6ef9 ("mm: larger stack guard gap, between vmas")
That should be 1be7107fbe18, yes?
> Debugged-by: Vlastimil Babka <vbabka@suse.cz>
> Signed-off-by: Michal Hocko <mhocko@suse.com>
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[PATCH] mm: mm, mmap: do not blow on PROT_NONE MAP_FIXED holes in the stack Michal Hocko <mhocko@kernel.org> - 2017-07-05 19:00 +0200
Re: [PATCH] mm: mm, mmap: do not blow on PROT_NONE MAP_FIXED holes in the stack Linus Torvalds <torvalds@linux-foundation.org> - 2017-07-05 19:50 +0200
Re: [PATCH] mm: mm, mmap: do not blow on PROT_NONE MAP_FIXED holes in the stack Michal Hocko <mhocko@kernel.org> - 2017-07-05 20:30 +0200
Re: [PATCH] mm: mm, mmap: do not blow on PROT_NONE MAP_FIXED holes in the stack Linus Torvalds <torvalds@linux-foundation.org> - 2017-07-05 20:40 +0200
Re: [PATCH] mm: mm, mmap: do not blow on PROT_NONE MAP_FIXED holes in the stack Michal Hocko <mhocko@kernel.org> - 2017-07-05 21:00 +0200
Re: [PATCH] mm: mm, mmap: do not blow on PROT_NONE MAP_FIXED holes in the stack Linus Torvalds <torvalds@linux-foundation.org> - 2017-07-05 21:20 +0200
Re: [PATCH] mm: mm, mmap: do not blow on PROT_NONE MAP_FIXED holes in the stack Willy Tarreau <w@1wt.eu> - 2017-07-05 21:20 +0200
Re: [PATCH] mm: mm, mmap: do not blow on PROT_NONE MAP_FIXED holes in the stack Michal Hocko <mhocko@kernel.org> - 2017-07-05 21:20 +0200
Re: [PATCH] mm: mm, mmap: do not blow on PROT_NONE MAP_FIXED holes in the stack Andrew Morton <akpm@linux-foundation.org> - 2017-07-05 23:20 +0200
Re: [PATCH] mm: mm, mmap: do not blow on PROT_NONE MAP_FIXED holes in the stack Linus Torvalds <torvalds@linux-foundation.org> - 2017-07-05 23:50 +0200
Re: [PATCH] mm: mm, mmap: do not blow on PROT_NONE MAP_FIXED holes in the stack Michal Hocko <mhocko@kernel.org> - 2017-07-06 08:50 +0200
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