...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.durr...@citrix.com>
---
Cc: Jan Beulich <jbeul...@suse.com>
Cc: Andrew Cooper <andrew.coop...@citrix.com>
Cc: Wei Liu <w...@xen.org>
Cc: "Roger Pau Monné" <roger....@citrix.com>
---
xen/arch/x86/hvm/viridian/time.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/xen/arch/x86/hvm/viridian/time.c b/xen/arch/x86/hvm/viridian/time.c
index ac087383c8..e80330a6ae 100644
--- a/xen/arch/x86/hvm/viridian/time.c
+++ b/xen/arch/x86/hvm/viridian/time.c
@@ -296,7 +296,7 @@ void viridian_time_poll_timers(struct vcpu *v)
poll_stimer(v, i);
}
-void viridian_time_vcpu_freeze(struct vcpu *v)
+static void viridian_time_vcpu_freeze(struct vcpu *v)
{
struct viridian_vcpu *vv = v->arch.hvm.viridian;
unsigned int i;
@@ -314,7 +314,7 @@ void viridian_time_vcpu_freeze(struct vcpu *v)
}
}
-void viridian_time_vcpu_thaw(struct vcpu *v)
+static void viridian_time_vcpu_thaw(struct vcpu *v)
{
struct viridian_vcpu *vv = v->arch.hvm.viridian;
unsigned int i;
@@ -336,7 +336,7 @@ void viridian_time_domain_freeze(const struct domain *d)
{
struct vcpu *v;
- if ( !is_viridian_domain(d) )
+ if ( d->is_dying || !is_viridian_domain(d) )
return;
for_each_vcpu ( d, v )
@@ -349,7 +349,7 @@ void viridian_time_domain_thaw(const struct domain *d)
{
struct vcpu *v;
- if ( !is_viridian_domain(d) )
+ if ( d->is_dying || !is_viridian_domain(d) )
return;
time_ref_count_thaw(d);
--
2.20.1.2.gb21ebb671
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