From a84bf5eaa10c2db8856c7497b63ae3caceac8c17 Mon Sep 17 00:00:00 2001 From: Mitchell Horne Date: Sat, 14 May 2022 10:23:08 -0300 Subject: [PATCH] debugnet: fix an errant assertion We may call debugnet_free() before g_debugnet_pcb_inuse is true, specifically in the cases where the interface is down or does not support debugnet. pcb->dp_drv_input is used to hold the real driver if_input callback while debugnet is in use, so we can check the status of this field in the assertion. This can be triggered trivially by trying to configure netdump on an unsupported interface at the ddb prompt. Initializing the dp_drv_input field to NULL explicitly is not necessary but helps display the intent. PR: 263929 Reported by: Martin Filla Reviewed by: cem, markj MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D35179 --- sys/net/debugnet.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/sys/net/debugnet.c b/sys/net/debugnet.c index 7a2c98ace65d..fa8d64ab86c8 100644 --- a/sys/net/debugnet.c +++ b/sys/net/debugnet.c @@ -605,8 +605,8 @@ debugnet_free(struct debugnet_pcb *pcb) { struct ifnet *ifp; - MPASS(g_debugnet_pcb_inuse); MPASS(pcb == &g_dnet_pcb); + MPASS(pcb->dp_drv_input == NULL || g_debugnet_pcb_inuse); ifp = pcb->dp_ifp; if (ifp != NULL) { @@ -646,6 +646,7 @@ debugnet_connect(const struct debugnet_conn_params *dcp, .dp_seqno = 1, .dp_ifp = dcp->dc_ifp, .dp_rx_handler = dcp->dc_rx_handler, + .dp_drv_input = NULL, }; /* Switch to the debugnet mbuf zones. */