From: Sam Bobroff <sam.bobroff@au1.ibm.com>
Date: Thu, 18 Sep 2014 23:40:41 +0000 (+1000)
Subject: KVM: correct null pid check in kvm_vcpu_yield_to()
X-Git-Tag: firefly_0821_release~3680^2~36^2~16^2^2
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=b8a669d29702a8fb529f4fae450a86b8676b0e42;p=firefly-linux-kernel-4.4.55.git

KVM: correct null pid check in kvm_vcpu_yield_to()

Correct a simple mistake of checking the wrong variable
before a dereference, resulting in the dereference not being
properly protected by rcu_dereference().

Signed-off-by: Sam Bobroff <sam.bobroff@au1.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit 27fbe64bfa63cfb9da025975b59d96568caa2d53)
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
---

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index b64d44219f27..9cae94206f41 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1728,7 +1728,7 @@ bool kvm_vcpu_yield_to(struct kvm_vcpu *target)
 	rcu_read_lock();
 	pid = rcu_dereference(target->pid);
 	if (pid)
-		task = get_pid_task(target->pid, PIDTYPE_PID);
+		task = get_pid_task(pid, PIDTYPE_PID);
 	rcu_read_unlock();
 	if (!task)
 		return ret;