From: "Roger Pau Monné" <roger.pau@citrix.com>
To: Paul Durrant <paul.durrant@citrix.com>
Cc: xen-devel@lists.xenproject.org, Wei Liu <wl@xen.org>,
Jan Beulich <jbeulich@suse.com>,
Andrew Cooper <andrew.cooper3@citrix.com>
Subject: Re: [Xen-devel] [PATCH] viridian: make viridian_time_domain_freeze() safe to call...
Date: Wed, 21 Aug 2019 10:52:10 +0200 [thread overview]
Message-ID: <20190821085210.kjx53rseieu2uc5k@Air-de-Roger> (raw)
In-Reply-To: <20190821082258.36549-1-paul.durrant@citrix.com>
On Wed, Aug 21, 2019 at 09:22:58AM +0100, Paul Durrant wrote:
> ...on a partially destroyed domain.
>
> viridian_time_domain_freeze() and viridian_time_vcpu_freeze() rely
> (respectively) on the dynamically allocated per-domain and per-vcpu viridian
> areas [1], which are freed during domain_relinquish_resources().
> Because arch_domain_pause() can call viridian_domain_time_freeze() this
> can lead to host crashes if e.g. a XEN_DOMCTL_pausedomain is issued after
> domain_relinquish_resources() has run.
>
> To prevent such crashes, this patch adds a check of is_dying into
> viridian_time_domain_freeze(), and viridian_time_domain_thaw() which is
> similarly vulnerable to indirection into freed memory.
>
> NOTE: The patch also makes viridian_time_vcpu_freeze/thaw() static, since
> they have no callers outside of the same source module.
>
> [1] See commit e7a9b5e72f26 "viridian: separately allocate domain and vcpu
> structures".
>
> Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Note you could also drop the viridian_ prefix to the now static
functions.
Thanks, Roger.
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next prev parent reply other threads:[~2019-08-21 8:53 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-21 8:22 [Xen-devel] [PATCH] viridian: make viridian_time_domain_freeze() safe to call Paul Durrant
2019-08-21 8:52 ` Roger Pau Monné [this message]
2019-08-21 9:13 ` Paul Durrant
2019-08-21 10:17 ` Andrew Cooper
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