panic: malformed IPv4 option passed to ip_optcopy Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *325339 34117 0 0 0x4000000 0 syz-executor0 db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:399 panic() at panic+0x147 sys/kern/subr_prf.c:208 ip_fragment(b02cf271ae1c9ba9,ffffff00317f6b00,ffff800000171290) at ip_fragment+0x551 ip_output(d6acbf55643fe350,ffffff00317f6100,ffffff00317f6b00,0,ffffff0036f2aaf0,ffffff0036341d88) at ip_output+0xc06 sys/netinet/ip_output.c:501 udp_output(fbe5f313d049b7d6,1400,ffffff0036341d88,0) at udp_output+0x444 sys/netinet/udp_usrreq.c:1004 sosend(423b499ed931f857,ffffff00308ff4c0,ffff800014a81ea0,ffff800014a81f50,1000,0) at sosend+0x46c sys/kern/uipc_socket.c:513 dofilewritev(123caf92a4d716e6,ffff8000ffff8968,ffff800014a81f50,1000,ffff800014a81f68) at dofilewritev+0x148 sys/kern/sys_generic.c:364 sys_write(94ae68df3eedf610,ffff800014a81ff0,ffff8000ffff8968) at sys_write+0x7b sys/kern/sys_generic.c:283 syscall(c729342e4b6769e4) at syscall+0x3de Xsyscall(6,0,c,0,3,b210789e010) at Xsyscall+0x128 end of kernel end trace frame: 0xb235c721ff0, count: 5 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> ddb> set $lines = 0 ddb> show panic malformed IPv4 option passed to ip_optcopy ddb> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:399 panic() at panic+0x147 sys/kern/subr_prf.c:208 ip_fragment(b02cf271ae1c9ba9,ffffff00317f6b00,ffff800000171290) at ip_fragment+0x551 ip_output(d6acbf55643fe350,ffffff00317f6100,ffffff00317f6b00,0,ffffff0036f2aaf0,ffffff0036341d88) at ip_output+0xc06 sys/netinet/ip_output.c:501 udp_output(fbe5f313d049b7d6,1400,ffffff0036341d88,0) at udp_output+0x444 sys/netinet/udp_usrreq.c:1004 sosend(423b499ed931f857,ffffff00308ff4c0,ffff800014a81ea0,ffff800014a81f50,1000,0) at sosend+0x46c sys/kern/uipc_socket.c:513 dofilewritev(123caf92a4d716e6,ffff8000ffff8968,ffff800014a81f50,1000,ffff800014a81f68) at dofilewritev+0x148 sys/kern/sys_generic.c:364 sys_write(94ae68df3eedf610,ffff800014a81ff0,ffff8000ffff8968) at sys_write+0x7b sys/kern/sys_generic.c:283syscall(c729342e4b6769e4) at syscall+0x3de Xsyscall(6,0,c,0,3,b210789e010) at Xsyscall+0x128 end of kernel end trace frame: 0xb235c721ff0, count: -10 ddb> show registers rdi 0xffffffff81ef8a48 kprintf_mutex rsi 0xffffffff81854217 db_enter+0x17 rbp 0xffff800014a81ad0 rbx 0xffff800014a81b70 rdx 0xffff800002ad0000 rcx 0x1762 __ALIGN_SIZE+0x762 rax 0xffff800002ad0000 r8 0xffff800014a81aa0 r9 0 r10 0xffff800014a81940 r11 0x36d0ef27df255282 r12 0x3000000008 r13 0xffff800014a81ae0 r14 0x100 r15 0xffffffff81c46c02 substchar+0x100c7 rip 0xffffffff81854218 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff800014a81ac0 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (syz-executor0) pid=325339 stat=onproc flags process=0 proc=4000000 pri=81, usrpri=81, nice=20 forw=0xffffffffffffffff, list=0xffff8000ffff84b8,0xffffffff81f79578 process=0xffff8000ffff53d0 user=0xffff800014a7d000, vmspace=0xffffff003f12bb58 estcpu=36, cpticks=0, pctcpu=0.0 user=0, sys=0, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 34117 385036 4552 0 2 0 syz-executor0 *34117 325339 4552 0 7 0x4000000 syz-executor0 25349 49815 0 0 3 0x14200 bored sosplice 4552 93895 45007 0 3 0x82 nanosleep syz-executor0 62474 44775 45007 0 2 0x2 syz-executor1 45007 208449 49571 0 3 0x82 thrsleep syz-fuzzer 45007 400337 49571 0 3 0x4000082 nanosleep syz-fuzzer 45007 238821 49571 0 3 0x4000082 thrsleep syz-fuzzer 45007 380638 49571 0 3 0x4000082 kqread syz-fuzzer 45007 522696 49571 0 3 0x4000082 thrsleep syz-fuzzer 45007 508896 49571 0 3 0x4000082 thrsleep syz-fuzzer 45007 511798 49571 0 3 0x4000082 thrsleep syz-fuzzer 49571 416268 24964 0 3 0x10008a pause ksh 24964 336688 9018 0 3 0x92 select sshd 55378 354025 1 0 3 0x100083 ttyin getty 9018 3743 1 0 3 0x80 select sshd 24910 26719 50077 73 3 0x100090 kqread syslogd 50077 123304 1 0 3 0x100082 netio syslogd 18995 185223 1 77 3 0x100090 poll dhclient 91317 147860 1 0 3 0x80 poll dhclient 74756 440678 0 0 2 0x14200 zerothread 18204 390876 0 0 3 0x14200 aiodoned aiodoned 76070 516441 0 0 3 0x14200 syncer update 9781 68148 0 0 3 0x14200 cleaner cleaner 6768 466859 0 0 3 0x14200 reaper reaper 80461 329635 0 0 3 0x14200 pgdaemon pagedaemon 96790 501879 0 0 3 0x14200 bored crynlk 86513 335674 0 0 3 0x14200 bored crypto 4905 208939 0 0 3 0x40014200 acpi0 acpi0 72518 151095 0 0 3 0x14200 bored softnet 74741 48080 0 0 3 0x14200 bored systqmp 43981 517270 0 0 3 0x14200 bored systq 48955 417817 0 0 3 0x40014200 bored softclock 15931 302799 0 0 3 0x40014200 idle0 1 288400 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper