Add a dying flag to prevent races at detach.

I tried re-ordering ether_ifdetach(), but this created a new race
where sometimes, when under heavy receive load (>1Mpps) and running
tcpdump, the machine would panic.  At panic, the ithread was still in
the original (not dead) if_input() path, and was accessing stale BPF
data structs.  By using a dying flag, I can close the interface prior
to if_detach() to be certain the interface cannot send packets up in
the middle of ether_ifdetach.

1 files changed, 1 insertions, 0 deletions

diff --git a/sys/dev/mxge/if_mxge_var.h b/sys/dev/mxge/if_mxge_var.h
index 8d1da2e..47c39b5 100644
--- a/sys/dev/mxge/if_mxge_var.h
+++ b/sys/dev/mxge/if_mxge_var.h
@@ -266,6 +266,7 @@ struct mxge_softc {
 	int need_media_probe;
 	int num_slices;
 	int rx_ring_size;
+	int dying;
 	mxge_dma_t dmabench_dma;
 	struct callout co_hdl;
 	struct sysctl_oid *slice_sysctl_tree;