From: Jeff Xu <jeffxu@chromium.org>
To: Pedro Falcato <pedro.falcato@gmail.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>,
akpm@linux-foundation.org, keescook@chromium.org,
torvalds@linux-foundation.org, usama.anjum@collabora.com,
corbet@lwn.net, Liam.Howlett@oracle.com, jeffxu@google.com,
jorgelo@chromium.org, groeck@chromium.org,
linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
linux-mm@kvack.org, jannh@google.com, sroettger@google.com,
linux-hardening@vger.kernel.org, willy@infradead.org,
gregkh@linuxfoundation.org, deraadt@openbsd.org,
surenb@google.com, merimus@google.com, rdunlap@infradead.org
Subject: Re: [PATCH] munmap sealed memory cause memory to split (bug)
Date: Thu, 17 Oct 2024 13:12:36 -0700 [thread overview]
Message-ID: <CABi2SkWBFZkWxDPnc6g2odvvNuMQqL4wQcbQSN2cTow2JLMKJw@mail.gmail.com> (raw)
In-Reply-To: <zcizwa4wasrq5si6nsjvougg2lt2dklaujpshdmghwg7oejhlj@zxzqhyff4vba>
On Thu, Oct 17, 2024 at 12:14 PM Pedro Falcato <pedro.falcato@gmail.com> wrote:
>
> On Thu, Oct 17, 2024 at 09:20:20AM -0700, Jeff Xu wrote:
> > On Thu, Oct 17, 2024 at 1:18 AM Lorenzo Stoakes
> > <lorenzo.stoakes@oracle.com> wrote:
> > >
> > > NACK. Greg's bot got to it but...
> > >
> > > As per Greg's bot, no signed-off-by line.
> > >
> > Sorry for confusion, I wasn't meant to send this as a PATCH, but
> > reporting the issue.
> > The diff was just sent as reference to repro the bug, and I forgot to
> > remove PATCH from the title. I apologize for the confusion.
> >
>
> Can you explain what the issue is? I don't get it.
>
The issue is there is one VMA that gets splitted after an unmap call fails.
Two splitted VMA share the same attributes. e.g.
- Allocate 12 pages (0-11).
- Seal middle 4 pages (4567)
- munmap (2345) - this will fail due to 4567 being sealed.
The VMA for page (0123) is split as 2 VMAs (01)-(23), those 2 VMA
have the same attribute, and should be merged as one.
> --
> Pedro
next prev parent reply other threads:[~2024-10-17 20:12 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-10-17 2:26 jeffxu
2024-10-17 2:38 ` Jeff Xu
2024-10-17 6:03 ` Greg KH
2024-10-17 16:17 ` Jeff Xu
2024-10-17 8:18 ` Lorenzo Stoakes
2024-10-17 16:20 ` Jeff Xu
2024-10-17 19:14 ` Pedro Falcato
2024-10-17 19:16 ` Lorenzo Stoakes
2024-10-17 20:12 ` Jeff Xu [this message]
2024-10-17 9:46 ` Lorenzo Stoakes
2024-10-17 9:48 ` Lorenzo Stoakes
2024-10-17 9:59 ` Lorenzo Stoakes
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