From: Michael Kelley <mikelley@xxxxxxxxxxxxx> 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. Signed-off-by: Michael Kelley <mikelley@xxxxxxxxxxxxx> --- drivers/hv/hv.c | 7 ++++++- 1 files changed, 6 insertions(+), 1 deletions(-) diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c index 12e7bae..47ed538 100644 --- a/drivers/hv/hv.c +++ b/drivers/hv/hv.c @@ -82,9 +82,14 @@ 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; } -- 1.7.1 _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
