illumos gate

While experimenting with something else, I experienced a panic due to the vioif driver failing to attach.

panic[cpu0]/thread=fffffe00082c8c20: assertion failed: MUTEX_HELD(&vif->vif_mutex), file: ../../common/io/vioif/vioif.c, line: 360

Warning - stack not written to the dump buffer
fffffe00082c88a0 fffffffffba4a355 ()
fffffe00082c8900 vioif:vioif_free_bufs+487 ()
fffffe00082c8960 vioif:vioif_attach+298 ()
fffffe00082c89d0 genunix:devi_attach+b1 ()
fffffe00082c8a10 genunix:attach_node+8b ()
fffffe00082c8a60 genunix:i_ndi_config_node+118 ()
fffffe00082c8a90 genunix:i_ddi_attachchild+3e ()
fffffe00082c8ad0 genunix:devi_attach_node+64 ()
fffffe00082c8b50 genunix:config_immediate_children+c0 ()
fffffe00082c8ba0 genunix:devi_config_common+6a ()
fffffe00082c8c00 genunix:mt_config_thread+10b ()
fffffe00082c8c10 unix:thread_start+b ()

The cause is that the fail: block in vioif_attach() calls vioif_free_bufs() without holding vif->vif_mutex.