>Synopsis: Encountered bus error on tcpdumping a cycled interface >Category: system >Environment: System : OpenBSD 6.9 Details : OpenBSD 6.9 (GENERIC.MP) #551: Sun Apr 18 03:06:59 MDT 2021 dera...@octeon.openbsd.org:/usr/src/sys/arch/octeon/compile/GENERIC.MP
Architecture: OpenBSD.octeon Machine : octeon >Description: I cycled a vlan (vlan6) interface to down and then back to up with ifconfig to see if there is traffic flowing I tried tcpdumping and encountered a SIGBUS. Here is what I see: eta# tcpdump -v -n -i vlan6 tcpdump: listening on vlan6, link-type EN10MB Bus error eta# ifconfig vlan6 vlan6: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500 lladdr fc:ec:da:04:8d:69 description: RPI Freifunk Franken VLAN index 11 priority 0 llprio 3 encap: vnetid 6 parent cnmac1 txprio packet rxprio outer groups: vlan media: Ethernet autoselect (1000baseT full-duplex) status: active inet 192.168.36.1 netmask 0xffffff00 broadcast 192.168.36.255 A particular ktrace/kdump revealed this: 47271 tcpdump RET fstat 0 47271 tcpdump CALL mmap(0,0x10000,0x3<PROT_READ|PROT_WRITE>,0x1002<MAP_PRIVATE|MAP_ANON>,-1,0) 47271 tcpdump RET mmap 252174057472/0x3ab6bec000 47271 tcpdump CALL fcntl(1,F_ISATTY) 47271 tcpdump RET fcntl 1 47271 tcpdump PSIG SIGBUS SIG_DFL code BUS_ADRALN<1> addr=0x39f0f3c04c trapno=0 I assume the fcntl(... could be an isatty(3). >How-To-Repeat: No idea, I only upgraded this router today and added some networking including wireguard tunnels. >Fix: Not provided. There is mention in comments at: /usr/src/sys/arch/mips64/mips64/trap.c under BUS_ADRALN that this may be an unaligned memory access. dmesg: OpenBSD 6.9 (GENERIC.MP) #551: Sun Apr 18 03:06:59 MDT 2021 dera...@octeon.openbsd.org:/usr/src/sys/arch/octeon/compile/GENERIC.MP real mem = 536870912 (512MB) avail mem = 521322496 (497MB) random: good seed from bootblocks mainbus0 at root: board 20004 rev 0.16, model CN3xxx/CN5xxx cpu0 at mainbus0: CN50xx CPU rev 0.1 500 MHz, Software FP emulation cpu0: cache L1-I 32KB 4 way D 16KB 64 way, L2 128KB 8 way cpu1 at mainbus0: CN50xx CPU rev 0.1 500 MHz, Software FP emulation cpu1: cache L1-I 32KB 4 way D 16KB 64 way, L2 128KB 8 way clock0 at mainbus0: int 5 octcrypto0 at mainbus0 iobus0 at mainbus0 simplebus0 at iobus0: "soc" octciu0 at simplebus0 octsmi0 at simplebus0 octpip0 at simplebus0 octgmx0 at octpip0 interface 0 cnmac0 at octgmx0: port 0 RGMII, address fc:ec:da:04:8d:68 atphy0 at cnmac0 phy 7: AR8035 10/100/1000 PHY, rev. 2 cnmac1 at octgmx0: port 1 RGMII, address fc:ec:da:04:8d:69 atphy1 at cnmac1 phy 6: AR8035 10/100/1000 PHY, rev. 2 cnmac2 at octgmx0: port 2 RGMII, address fc:ec:da:04:8d:6a atphy2 at cnmac2 phy 5: AR8035 10/100/1000 PHY, rev. 2 com0 at simplebus0: ns16550a, 64 byte fifo com0: console dwctwo0 at iobus0 base 0x1180068000000 irq 56 usb0 at dwctwo0: USB revision 2.0 uhub0 at usb0 configuration 1 interface 0 "Octeon DWC2 root hub" rev 2.00/1.00 addr 1 octrng0 at iobus0 base 0x1400000000000 irq 0 umass0 at uhub0 port 1 configuration 1 interface 0 " UDinfo UF2 4GB" rev 2.00/1.00 addr 2 umass0: using SCSI over Bulk-Only scsibus0 at umass0: 2 targets, initiator 0 sd0 at scsibus0 targ 1 lun 0: <, UDinfo UF2 4GB, PMAP> removable serial.13fe420077C9177D2781 sd0: 3824MB, 512 bytes/sector, 7831552 sectors vscsi0 at root scsibus1 at vscsi0: 256 targets softraid0 at root scsibus2 at softraid0: 256 targets root on sd0a (d5ffec0c72cad730.a) swap on sd0b dump on sd0b WARNING: CHECK AND RESET THE DATE! usbdevs: Controller /dev/usb0: addr 01: 0000:0000 Octeon, DWC2 root hub high speed, self powered, config 1, rev 1.00 driver: uhub0 addr 02: 13fe:4200 , UDinfo UF2 4GB high speed, power 200 mA, config 1, rev 1.00, iSerial 070877C9177D2781 driver: umass0 pcidump: acpidump: