uvm_fault(0xfffffd806c5069a0, 0x4, 0, 1) -> e kernel: page fault trap, code=0 Stopped at igmp_leavegroup+0x80: movl 0x4(%rax),%r12d TID PID UID PRFLAGS PFLAGS CPU COMMAND igmp_leavegroup(ffff800000d14c00) at igmp_leavegroup+0x80 sys/netinet/igmp.c:521 in_delmulti(ffff800000d14c00) at in_delmulti+0xb7 sys/netinet/in.c:920 ip_freemoptions(ffff800000c1ef10) at ip_freemoptions+0x4d sys/netinet/ip_output.c:1764 in_pcbdetach(fffffd806f3b2e40) at in_pcbdetach+0xf3 sys/netinet/in_pcb.c:584 udp_detach(fffffd806e4ac710) at udp_detach+0x3b sys/netinet/udp_usrreq.c:1263 soclose(fffffd806e4ac710,0) at soclose+0x245 sys/kern/uipc_socket.c:361 soo_close(fffffd80713b7720,ffff80002165fa50) at soo_close+0x40 fdrop(fffffd80713b7720,ffff80002165fa50) at fdrop+0xc7 sys/kern/kern_descrip.c:1279 closef(fffffd80713b7720,ffff80002165fa50) at closef+0x117 sys/kern/kern_descrip.c:1263 fdfree(ffff80002165fa50) at fdfree+0xf3 sys/kern/kern_descrip.c:1195 exit1(ffff80002165fa50,0,0,1) at exit1+0x35d sys/kern/kern_exit.c:202 sys_exit(ffff80002165fa50,ffff800026d1f270,ffff800026d1f2d0) at sys_exit+0x16 sys/kern/kern_exit.c:95 syscall(ffff800026d1f340) at syscall+0x44e sys/arch/amd64/amd64/trap.c:585 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffef6f0, count: 1 https://www.openbsd.org/ddb.html describes the minimum info required in bug reports. Insufficient info makes it difficult to find and fix bugs.