Hi,
I’ve been playing around with a risc-v qemu image, and run into this
panic with vtnet:
DHCPDISCOVER on vtnet0 to 255.255.255.255 port 67 interval 5
panic: Assertion in_epoch(net_epoch_preempt) failed at
/usr/src/sys/net/netisr.c:1093
cpuid = 0
time = 1581981733
KDB: stack backtrace:
db_trace_self() at db_trace_self
db_fetch_ksymtab() at db_fetch_ksymtab+0x12a
kdb_backtrace() at kdb_backtrace+0x2c
vpanic() at vpanic+0x144
panic() at panic+0x26
netisr_dispatch_src() at netisr_dispatch_src+0x3c0
netisr_dispatch() at netisr_dispatch+0x10
ether_ifattach() at ether_ifattach+0x2fa
vtmmio_attach() at vtmmio_attach+0x490c
vtmmio_attach() at vtmmio_attach+0x4624
vtmmio_attach() at vtmmio_attach+0x544a
virtqueue_intr() at virtqueue_intr+0xc
vtmmio_attach() at vtmmio_attach+0x2008
db_dump_intr_event() at db_dump_intr_event+0x730
fork_exit() at fork_exit+0x68
fork_trampoline() at fork_trampoline+0xa
KDB: enter: panic
[ thread pid 12 tid 100023 ]
Stopped at kdb_enter+0x44: sd zero,0(a0)
db>
It seems pretty clear that the vtmmio path doesn’t enter epoch before
it runs the vtnet_attach() code.
On the other hand, I run vtnet CURRENT guests in bhyve, and don’t see
this panic. In that case it lives on top of PCI rather than mmio, but I
don’t see why/where that’d enter epoch.
The following does fix the panic for me, but I’m not sure if I’m
fixing the correct problem:
commit 4e388ab164c0d746875501d403a1c7052f1ed633 (HEAD -> kp-hardfloat)
Author: Kristof Provost <kris...@codepro.be>
Date: Mon Feb 17 10:05:14 2020 +0100
vtnet: Needs epoch
diff --git a/sys/dev/virtio/network/if_vtnet.c
b/sys/dev/virtio/network/if_vtnet.c
index ceb3ffaaf2b..8c776b27f21 100644
--- a/sys/dev/virtio/network/if_vtnet.c
+++ b/sys/dev/virtio/network/if_vtnet.c
@@ -950,7 +950,7 @@ vtnet_setup_interface(struct vtnet_softc *sc)
if_initname(ifp, device_get_name(dev), device_get_unit(dev));
ifp->if_baudrate = IF_Gbps(10); /* Approx. */
ifp->if_softc = sc;
- ifp->if_flags = IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST;
+ ifp->if_flags = IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST |
IFF_NEEDSEPOCH;
ifp->if_init = vtnet_init;
ifp->if_ioctl = vtnet_ioctl;
ifp->if_get_counter = vtnet_get_counter;
Best regards,
Kristof
_______________________________________________
freebsd-net@freebsd.org mailing list
https://lists.freebsd.org/mailman/listinfo/freebsd-net
To unsubscribe, send any mail to "freebsd-net-unsubscr...@freebsd.org"
