From: Avi Kivity <a...@redhat.com>
init_fpu() (which is indirectly called by the fpu switching code) assumes
it is in process context. Rather than makeing init_fpu() use an atomic
allocation, which can cause a task to be killed, make sure the fpu is
already initialized when we enter the run loop.
KVM-Stable-Tag.
Reported-and-tested-by: Kirill A. Shutemov <k...@openvz.org>
Acked-by: Pekka Enberg <penb...@kernel.org>
Reviewed-by: Christoph Lameter <c...@linux.com>
Signed-off-by: Avi Kivity <a...@redhat.com>
diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c
index 58bb239..e60c38c 100644
--- a/arch/x86/kernel/i387.c
+++ b/arch/x86/kernel/i387.c
@@ -169,6 +169,7 @@ int init_fpu(struct task_struct *tsk)
set_stopped_child_used_math(tsk);
return 0;
}
+EXPORT_SYMBOL_GPL(init_fpu);
/*
* The xstateregs_active() routine is the same as the fpregs_active() routine,
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index fa708c9..9dda70d 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5376,6 +5376,9 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct
kvm_run *kvm_run)
int r;
sigset_t sigsaved;
+ if (!tsk_used_math(current) && init_fpu(current))
+ return -ENOMEM;
+
if (vcpu->sigset_active)
sigprocmask(SIG_SETMASK, &vcpu->sigset, &sigsaved);
--
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