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Commit 13b9abfc authored by Michael Kelley's avatar Michael Kelley Committed by Greg Kroah-Hartman
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Drivers: hv: vmbus: Close timing hole that can corrupt per-cpu page 



Extend the disabling of preemption to include the hypercall so that
another thread can't get the CPU and corrupt the per-cpu page used
for hypercall arguments.

Cc: <Stable@vger.kernel.org> #4.11
Signed-off-by: default avatarMichael Kelley <mikelley@microsoft.com>
Signed-off-by: default avatarK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 31100108

drivers/hv/hv.c

+6 −1
Original line number Diff line number Diff line
@@ -82,10 +82,15 @@ int hv_post_message(union hv_connection_id connection_id, 
	aligned_msg->message_type = message_type;

	aligned_msg->payload_size = payload_size;

	memcpy((void *)aligned_msg->payload, payload, payload_size);

	put_cpu_ptr(hv_cpu);



	status = hv_do_hypercall(HVCALL_POST_MESSAGE, aligned_msg, NULL);



	/* Preemption must remain disabled until after the hypercall

	 * so some other thread can't get scheduled onto this cpu and

	 * corrupt the per-cpu post_msg_page

	 */

	put_cpu_ptr(hv_cpu);



	return status & 0xFFFF;

}