lguest: make sure cpu is initialized before accessing it
If req is LHREQ_INITIALIZE, and the guest has been initialized before (unlikely), it will attempt to access cpu->tsk even though cpu is not yet initialized. Signed-off-by: Eugene Teo <eugeneteo@kernel.sg> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
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@ -241,16 +241,17 @@ static ssize_t write(struct file *file, const char __user *in,
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cpu = &lg->cpus[cpu_id];
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if (!cpu)
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return -EINVAL;
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/* Once the Guest is dead, you can only read() why it died. */
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if (lg->dead)
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return -ENOENT;
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/* If you're not the task which owns the Guest, all you can do
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* is break the Launcher out of running the Guest. */
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if (current != cpu->tsk && req != LHREQ_BREAK)
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return -EPERM;
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}
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/* Once the Guest is dead, all you can do is read() why it died. */
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if (lg && lg->dead)
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return -ENOENT;
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/* If you're not the task which owns the Guest, you can only break */
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if (lg && current != cpu->tsk && req != LHREQ_BREAK)
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return -EPERM;
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switch (req) {
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case LHREQ_INITIALIZE:
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return initialize(file, input);
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