From: Peter Maydell <peter.maydell@linaro.org>
To: P J P <ppandit@redhat.com>
Cc: "Fam Zheng" <fam@euphon.net>,
"Prasad J Pandit" <pjp@fedoraproject.org>,
"QEMU Developers" <qemu-devel@nongnu.org>,
"Alexander Bulekov" <alxndr@bu.edu>,
"Marc-André Lureau" <marcandre.lureau@redhat.com>,
"Ding Ren" <rding@gatech.edu>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Philippe Mathieu-Daudé" <philmd@redhat.com>
Subject: Re: [PATCH v3] exec: set map length to zero when returning NULL
Date: Tue, 26 May 2020 11:19:12 +0100 [thread overview]
Message-ID: <CAFEAcA9N7n4mpznFBXgZeZnFXhCaeJwfwvJVeAc6U3W2mjQPAQ@mail.gmail.com> (raw)
In-Reply-To: <20200526075042.420162-1-ppandit@redhat.com>
On Tue, 26 May 2020 at 08:53, P J P <ppandit@redhat.com> wrote:
>
> From: Prasad J Pandit <pjp@fedoraproject.org>
>
> When mapping physical memory into host's virtual address space,
> 'address_space_map' may return NULL if BounceBuffer is in_use.
> Set and return '*plen = 0' to avoid later NULL pointer dereference.
>
> Reported-by: Alexander Bulekov <alxndr@bu.edu>
> Fixes: https://bugs.launchpad.net/qemu/+bug/1878259
> Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
The doc comment for this function in include/exec/memory.h
currently says
"May return %NULL if resources needed to perform the mapping
are exhausted."
If we're tightening the API to guarantee to also set *plen to 0
in this failure case it would be good to capture that in the
documentation, eg:
"May return %NULL (and set *@plen to 0) if resources needed
to perform the mapping are exhausted.)"
thanks
-- PMM
next prev parent reply other threads:[~2020-05-26 10:20 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-26 7:50 [PATCH v3] exec: set map length to zero when returning NULL P J P
2020-05-26 8:01 ` Philippe Mathieu-Daudé
2020-05-26 10:06 ` Philippe Mathieu-Daudé
2020-05-26 10:19 ` Peter Maydell [this message]
2020-05-26 11:18 ` P J P
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