Re: CVE request: kernel: thp: madvise on top of /dev/zero private mapping can lead to panic

[Josh Bressers <bressers () redhat com>]

----- Original Message -----
> Description of problem:
> The huge_memory.c THP page fault was allowed to run if vm_ops was null
> (which would succeed for /dev/zero MAP_PRIVATE, as the f_op->mmap
> wouldn't setup a special vma->vm_ops and it would fallback to regular
> anonymous memory) but other THP logics weren't fully activated for
> vmas with vm_file not NULL (/dev/zero has a not NULL vma->vm_file).
>
> Unprivileged local user could use this flaw to crash the server.
>
> Upstream patch: 78f11a255749d09025f54d4e2df4fbcb031530e2
>
> References:
> https://bugzilla.redhat.com/show_bug.cgi?id=714761
> https://bugzilla.kernel.org/show_bug.cgi?id=33682
> http://www.spinics.net/lists/stable-commits/msg11762.html

Please use CVE-2011-2479.

Thanks.

-- 
    JB