I am using XCP-ng with the latest OpenBSD snapshot.
Whenever I make an hardware change in networking on the VM (connect or
disconnect an interface, change associated network), the VM panics :
openbsd# panic: grant table reference 5912 is held by domain 0: frame 0x1f1a4
flags 0x19
Stopped at db_enter+0x10: popq %rbp
TID PID UID PRFLAGS PFLAGS CPU COMMAND
*349758 65579 0 0x14000 0x200 0 xenwatch
db_enter() at db_enter+0x10
panic(ffffffff81da7541) at panic+0x12a
xen_bus_dmamap_unload(ffffffff820ede50,ffff8000000e9380) at
xen_bus_dmamap_unload+0x138
xnf_tx_ring_destroy(ffff800000162000) at xnf_tx_ring_destroy+0x104
xnf_detach(ffff800000162000,0) at xnf_detach+0x55
config_detach(ffff800000162000,0) at config_detach+0x140
xen_hotplug(ffff80000012e200) at xen_hotplug+0x181
taskq_thread(ffff8000000dde00) at taskq_thread+0x66
end trace frame: 0x0, count: 7
https://www.openbsd.org/ddb.html describes the minimum info required in bug
reports. Insufficient info makes it difficult to find and fix bugs.
ddb>
If I apply the following patch, it obviously does not panic and seems to work
correctly :
Index: xen.c
===================================================================
RCS file: /cvs/src/sys/dev/pv/xen.c,v
retrieving revision 1.97
diff -u -p -r1.97 xen.c
--- xen.c 29 Jun 2020 06:50:52 -0000 1.97
+++ xen.c 31 Jan 2021 13:13:07 -0000
@@ -1204,7 +1204,7 @@ xen_grant_table_remove(struct xen_softc
loop = 0;
while (atomic_cas_uint(ptr, flags, GTF_invalid) != flags) {
if (loop++ > 10) {
- panic("grant table reference %u is held "
+ printf("grant table reference %u is held "
"by domain %d: frame %#x flags %#x",
ref + ge->ge_start, ge->ge_table[ref].domid,
ge->ge_table[ref].frame, ge->ge_table[ref].flags);
Can someone give me a clue on what _atomic_cas_uint() is ?
Thank you in advance.
Denis
OpenBSD 6.8-current (GENERIC) #9: Sun Jan 31 14:08:42 CET 2021
r...@openbsd.lab.ledeuns.net:/sys/arch/amd64/compile/GENERIC
real mem = 1052770304 (1004MB)
avail mem = 1005694976 (959MB)
random: good seed from bootblocks
mpath0 at root
scsibus0 at mpath0: 256 targets
mainbus0 at root
bios0 at mainbus0: SMBIOS rev. 2.4 @ 0xeb01f (11 entries)
bios0: vendor Xen version "4.13" date 01/21/2021
bios0: Xen HVM domU
acpi0 at bios0: ACPI 4.0
acpi0: sleep states S5
acpi0: tables DSDT FACP APIC HPET WAET
acpi0: wakeup devices
acpitimer0 at acpi0: 3579545 Hz, 32 bits
acpimadt0 at acpi0 addr 0xfee00000: PC-AT compat
ioapic0 at mainbus0: apid 1 pa 0xfec00000, version 11, 48 pins, remapped
cpu0 at mainbus0: apid 0 (boot processor)
cpu0: Intel(R) Xeon(R) CPU E5-2407 v2 @ 2.40GHz, 2394.83 MHz, 06-3e-04
cpu0:
FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CFLUSH,ACPI,MMX,FXSR,SSE,SSE2,SS,SSE3,PCLMUL,SSSE3,CX16,PCID,SSE4.1,SSE4.2,x2APIC,POPCNT,DEADLINE,AES,XSAVE,AVX,F16C,RDRAND,HV,NXE,PAGE1GB,RDTSCP,LONG,LAHF,FSGSBASE,SMEP,ERMS,MD_CLEAR,IBRS,IBPB,STIBP,L1DF,SSBD,XSAVEOPT,MELTDOWN
cpu0: 256KB 64b/line 8-way L2 cache
cpu0: smt 0, core 0, package 0
mtrr: Pentium Pro MTRR support, 8 var ranges, 88 fixed ranges
cpu0: apic clock running at 100MHz
acpihpet0 at acpi0: 62500000 Hz
acpiprt0 at acpi0: bus 0 (PCI0)
acpipci0 at acpi0 PCI0
acpicmos0 at acpi0
"ACPI0007" at acpi0 not configured
acpicpu0 at acpi0: C1(@1 halt!)
cpu0: using VERW MDS workaround (except on vmm entry)
pvbus0 at mainbus0: Hyper-V 0.0, Xen 4.13
xen0 at pvbus0: features 0x2705, 64 grant table frames, event channel 2
xbf0 at xen0 backend 0 channel 6: disk
scsibus1 at xbf0: 1 targets
sd0 at scsibus1 targ 0 lun 0: <Xen, phy xvda 768, 0000>
sd0: 10240MB, 512 bytes/sector, 20971520 sectors
xbf1 at xen0 backend 0 channel 7: cdrom
xbf1: timed out waiting for backend to connect
xnf0 at xen0 backend 0 channel 7: address 76:88:23:28:25:f4
xnf1 at xen0 backend 0 channel 8: address 62:36:ed:68:46:3c
xnf2 at xen0 backend 0 channel 9: address be:04:e2:f3:7d:75
pci0 at mainbus0 bus 0
pchb0 at pci0 dev 0 function 0 "Intel 82441FX" rev 0x02
pcib0 at pci0 dev 1 function 0 "Intel 82371SB ISA" rev 0x00
pciide0 at pci0 dev 1 function 1 "Intel 82371SB IDE" rev 0x00: DMA, channel 0
wired to compatibility, channel 1 wired to compatibility
pciide0: channel 0 disabled (no drives)
atapiscsi0 at pciide0 channel 1 drive 1
scsibus2 at atapiscsi0: 2 targets
cd0 at scsibus2 targ 0 lun 0: <QEMU, QEMU DVD-ROM, 0.10> removable
cd0(pciide0:1:1): using PIO mode 4, DMA mode 2
uhci0 at pci0 dev 1 function 2 "Intel 82371SB USB" rev 0x01: apic 1 int 23
piixpm0 at pci0 dev 1 function 3 "Intel 82371AB Power" rev 0x01: SMBus disabled
vga1 at pci0 dev 2 function 0 "Cirrus Logic CL-GD5446" rev 0x00
wsdisplay0 at vga1 mux 1: console (80x25, vt100 emulation)
wsdisplay0: screen 1-5 added (80x25, vt100 emulation)
xspd0 at pci0 dev 3 function 0 "XenSource Platform Device" rev 0x01
isa0 at pcib0
isadma0 at isa0
fdc0 at isa0 port 0x3f0/6 irq 6 drq 2
com0 at isa0 port 0x3f8/8 irq 4: ns16550a, 16 byte fifo
pckbc0 at isa0 port 0x60/5 irq 1 irq 12
pckbd0 at pckbc0 (kbd slot)
wskbd0 at pckbd0: console keyboard, using wsdisplay0
pms0 at pckbc0 (aux slot)
wsmouse0 at pms0 mux 0
pcppi0 at isa0 port 0x61
spkr0 at pcppi0
lpt0 at isa0 port 0x378/4 irq 7
usb0 at uhci0: USB revision 1.0
uhub0 at usb0 configuration 1 interface 0 "Intel UHCI root hub" rev 1.00/1.00
addr 1
uhidev0 at uhub0 port 2 configuration 1 interface 0 "QEMU 0.10.2 QEMU USB
Tablet" rev 1.00/0.00 addr 2
uhidev0: iclass 3/1
ums0 at uhidev0: 3 buttons, Z dir
wsmouse1 at ums0 mux 0
vscsi0 at root
scsibus3 at vscsi0: 256 targets
softraid0 at root
scsibus4 at softraid0: 256 targets
root on sd0a (bd7a4058a4c9a3e2.a) swap on sd0b dump on sd0b
fd0 at fdc0 drive 1: density unknown
xbf2 at xen0 backend 0 channel 10: disk
scsibus5 at xbf2: 1 targets
sd1 at scsibus5 targ 0 lun 0: <Xen, phy xvdb 832, 0000>
sd1: 4096MB, 512 bytes/sector, 8388608 sectors
WARNING: R/W mount of / denied. Filesystem is not clean - run fsck
grant table reference 6678 is held by domain 0: frame 0x1b178 flags 0x19sd1
detached
scsibus5 detached
xbf2 detached
