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From: Paolo Bonzini <pbonzini@redhat.com>
To: "Michael S. Tsirkin" <mst@redhat.com>, qemu-devel@nongnu.org
Cc: Kevin Wolf <kwolf@redhat.com>,
	Peter Maydell <peter.maydell@linaro.org>,
	Michael Tokarev <mjt@tls.msk.ru>
Subject: Re: [Qemu-devel] [PATCH repost 2/4] oslib: allocate PROT_NONE pages on top of RAM
Date: Mon, 28 Sep 2015 12:59:43 +0200	[thread overview]
Message-ID: <56091D9F.9040704@redhat.com> (raw)
In-Reply-To: <1443348833-22760-3-git-send-email-mst@redhat.com>



On 27/09/2015 12:14, Michael S. Tsirkin wrote:
> -    if (total > size) {
> -        munmap(ptr + size, total - size);
> +    if (total > size + getpagesize()) {
> +        munmap(ptr + size + getpagesize(), total - size - getpagesize());
>      }
>  

Please add a comment here, also noting that "total" always allocates at
least an extra page, even if size is already aligned.

>      if (ptr) {
> -        munmap(ptr, size);
> +        munmap(ptr, size + getpagesize());
>      }

And another comment here.

Paolo

  reply	other threads:[~2015-09-28 10:59 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-09-27 10:14 [Qemu-devel] [PATCH repost 0/4] add mitigation against buffer overflows Michael S. Tsirkin
2015-09-27 10:14 ` [Qemu-devel] [PATCH repost 1/4] oslib: rework anonimous RAM allocation Michael S. Tsirkin
2015-09-27 10:14 ` [Qemu-devel] [PATCH repost 2/4] oslib: allocate PROT_NONE pages on top of RAM Michael S. Tsirkin
2015-09-28 10:59   ` Paolo Bonzini [this message]
2015-09-27 10:14 ` [Qemu-devel] [PATCH repost 3/4] exec: " Michael S. Tsirkin
2015-09-27 10:14 ` [Qemu-devel] [PATCH repost 4/4] exec: factor out duplicate mmap code Michael S. Tsirkin
2015-09-30 13:12   ` Marc-André Lureau
2015-09-28 11:01 ` [Qemu-devel] [PATCH repost 0/4] add mitigation against buffer overflows Paolo Bonzini

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