uvm_fault(0xffffffff839a2008, 0xffff80000152d000, 0, 1) -> e kernel: page fault trap, code=0 Stopped at memcpy+0x19: repe movsq (%rsi),%es:(%rdi) TID PID UID PRFLAGS PFLAGS CPU COMMAND *184876 80417 0 0 0x4000000 0 syz-executor memcpy() at memcpy+0x19 rtm_msg1(14,ffff80003813eea8) at rtm_msg1+0x306 sys/net/rtsock.c:1644 rtm_addr(14,ffff80000152cf00) at rtm_addr+0xb9 sys/net/rtsock.c:-1 in6_update_ifa(ffff800000b12800,ffff80003813f2c0,ffff80000152cf00) at in6_update_ifa+0x1752 sys/netinet6/in6.c:741 in6_ioctl_change_ifaddr(8080691a,ffff80003813f2c0,ffff800000b12800) at in6_ioctl_change_ifaddr+0x644 sys/netinet6/in6.c:352 ifioctl(ffff8000014a6698,8080691a,ffff80003813f2c0,ffff80003c963c60) at ifioctl+0x1519 pru_control sys/sys/protosw.h:352 [inline] ifioctl(ffff8000014a6698,8080691a,ffff80003813f2c0,ffff80003c963c60) at ifioctl+0x1519 sys/net/if.c:2454 sys_ioctl(ffff80003c963c60,ffff80003813f4a0,ffff80003813f3f0) at sys_ioctl+0x5bf sys/kern/sys_generic.c:-1 syscall(ffff80003813f4a0) at syscall+0x97e mi_syscall sys/sys/syscall_mi.h:-1 [inline] syscall(ffff80003813f4a0) at syscall+0x97e sys/arch/amd64/amd64/trap.c:748 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x627f19c4f0, count: 6 https://www.openbsd.org/ddb.html describes the minimum info required in bug reports. Insufficient info makes it difficult to find and fix bugs.