From: Oleg Nesterov <oleg@redhat.com>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Ingo Molnar <mingo@kernel.org>,
Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/3] uprobes: fix the usage of install_special_mapping()
Date: Fri, 10 Jul 2015 00:02:25 +0200 [thread overview]
Message-ID: <20150709220225.GB15485@redhat.com> (raw)
In-Reply-To: <CALCETrU6_7RXG0YWWNVUWnvQv+inEG4EKLmOUckrVUOsxg4=qA@mail.gmail.com>
On 07/09, Andy Lutomirski wrote:
>
> On Thu, Jul 9, 2015 at 2:44 PM, Oleg Nesterov <oleg@redhat.com> wrote:
> > install_special_mapping(pages) expects that "pages" is the zero-
> > terminated array while xol_add_vma() passes &area->page, this means
> > that special_mapping_fault() can wrongly use the next member in
> > xol_area (vaddr) as "struct page *".
> >
> > Fortunately, this area is not expandable so pgoff != 0 isn't possible
> > (modulo bugs in special_mapping_vmops), but still this does not look
> > good.
> >
>
> I fell for that awhile back, too, causing a bizarre HPET bug.
I guess you mean no_pages[] = {NULL} in map_vdso() ?
uprobes differs, I think pgoff != 0 is not actually possible (assuming
we fix special_mapping_fault). But this doesn't matter, this is wrong
anyway.
> What zeroes pages[1]?
Heh ;) Thanks. I'll send v2.
Oleg.
next prev parent reply other threads:[~2015-07-09 22:04 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-09 21:44 uprobes: minor fixes + name the xol vma Oleg Nesterov
2015-07-09 21:44 ` [PATCH 1/3] uprobes: fix the usage of install_special_mapping() Oleg Nesterov
2015-07-09 21:49 ` Andy Lutomirski
2015-07-09 22:02 ` Oleg Nesterov [this message]
2015-07-09 22:12 ` Andy Lutomirski
2015-07-09 21:44 ` [PATCH 2/3] uprobes: use vm_special_mapping to name the xol vma Oleg Nesterov
2015-07-09 21:50 ` Andy Lutomirski
2015-07-09 22:03 ` Oleg Nesterov
2015-07-09 21:44 ` [PATCH 3/3] uprobes: fix the waitqueue_active() check in xol_free_insn_slot() Oleg Nesterov
2015-07-09 22:25 ` [PATCH v2 0/3] uprobes: minor fixes + name the xol vma Oleg Nesterov
2015-07-09 22:25 ` [PATCH v2 1/3] uprobes: fix the usage of install_special_mapping() Oleg Nesterov
2015-07-09 22:25 ` [PATCH v2 2/3] uprobes: use vm_special_mapping to name the xol vma Oleg Nesterov
2015-07-09 22:25 ` [PATCH v2 3/3] uprobes: fix the waitqueue_active() check in xol_free_insn_slot() Oleg Nesterov
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