[src/trunk]: src/sys/dev/pci Fix a panic caused while detaching iavf(4)

[yamaguchi <yamaguchi%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/b6f6f8475b74
branches:  trunk
changeset: 938856:b6f6f8475b74
user:      yamaguchi <yamaguchi%NetBSD.org@localhost>
date:      Thu Sep 17 06:34:43 2020 +0000

description:
Fix a panic caused while detaching iavf(4)

The sequence of the panic is follow:
  1. failed to disable queues in iavf_stop()
  2. release ec->ec_lock in ether_ifdetach()
  3. do reset scheduled at iavf_stop()
  4. acquire ec->ec_lock in iavf_reset_finish()
    - panic

reviewed by knakahara@n.o, thanks.

diffstat:

 sys/dev/pci/if_iavf.c |  40 +++++++++++++++++++++++++---------------
 1 files changed, 25 insertions(+), 15 deletions(-)

diffs (94 lines):

diff -r 87f63f005e88 -r b6f6f8475b74 sys/dev/pci/if_iavf.c
--- a/sys/dev/pci/if_iavf.c     Thu Sep 17 02:17:51 2020 +0000
+++ b/sys/dev/pci/if_iavf.c     Thu Sep 17 06:34:43 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: if_iavf.c,v 1.5 2020/09/10 03:20:08 yamaguchi Exp $    */
+/*     $NetBSD: if_iavf.c,v 1.6 2020/09/17 06:34:43 yamaguchi Exp $    */
 
 /*
  * Copyright (c) 2013-2015, Intel Corporation
@@ -75,7 +75,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: if_iavf.c,v 1.5 2020/09/10 03:20:08 yamaguchi Exp $");
+__KERNEL_RCSID(0, "$NetBSD: if_iavf.c,v 1.6 2020/09/17 06:34:43 yamaguchi Exp $");
 
 #include <sys/param.h>
 #include <sys/types.h>
@@ -94,6 +94,7 @@
 #include <sys/queue.h>
 #include <sys/syslog.h>
 #include <sys/workqueue.h>
+#include <sys/xcall.h>
 
 #include <net/bpf.h>
 #include <net/if.h>
@@ -626,6 +627,13 @@
 #define iavf_allqueues(_sc)    ((1 << ((_sc)->sc_nqueue_pairs)) - 1)
 
 static inline void
+iavf_intr_barrier(void)
+{
+
+       /* make all interrupt handler finished */
+       xc_barrier(0);
+}
+static inline void
 iavf_intr_enable(struct iavf_softc *sc)
 {
 
@@ -965,38 +973,40 @@
                return 0;
 
        iavf_stop(ifp, 1);
-       ether_ifdetach(ifp);
-       if_detach(ifp);
-       ifmedia_fini(&sc->sc_media);
-       if_percpuq_destroy(sc->sc_ipq);
-
-       iavf_intr_disable(sc);
-
-       mutex_enter(&sc->sc_adminq_lock);
-       mutex_exit(&sc->sc_adminq_lock);
 
        /*
         * set a dummy function to halt callout safely
         * even if a workqueue entry calls callout_schedule()
         */
        callout_setfunc(&sc->sc_tick, iavf_tick_halt, sc);
-
        iavf_work_wait(sc->sc_workq, &sc->sc_reset_task);
-       iavf_work_wait(sc->sc_workq, &sc->sc_arq_refill);
        iavf_work_wait(sc->sc_workq, &sc->sc_wdto_task);
-       iavf_workq_destroy(sc->sc_workq);
-       sc->sc_workq = NULL;
 
        callout_halt(&sc->sc_tick, NULL);
        callout_destroy(&sc->sc_tick);
 
+       /* detach the I/F before stop adminq due to callbacks */
+       ether_ifdetach(ifp);
+       if_detach(ifp);
+       ifmedia_fini(&sc->sc_media);
+       if_percpuq_destroy(sc->sc_ipq);
+
+       iavf_intr_disable(sc);
+       iavf_intr_barrier();
+       iavf_work_wait(sc->sc_workq, &sc->sc_arq_refill);
+
+       mutex_enter(&sc->sc_adminq_lock);
        iavf_cleanup_admin_queue(sc);
+       mutex_exit(&sc->sc_adminq_lock);
        iavf_aqb_clean(&sc->sc_atq_idle, sc->sc_dmat);
        iavf_aqb_clean(&sc->sc_arq_idle, sc->sc_dmat);
        iavf_dmamem_free(sc->sc_dmat, &sc->sc_arq);
        iavf_dmamem_free(sc->sc_dmat, &sc->sc_atq);
        cv_destroy(&sc->sc_adminq_cv);
 
+       iavf_workq_destroy(sc->sc_workq);
+       sc->sc_workq = NULL;
+
        iavf_queue_pairs_free(sc);
        iavf_teardown_interrupts(sc);
        iavf_teardown_sysctls(sc);