panic: malformed IPv4 option passed to ip_optcopy Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *265534 43745 0 0 0x4000000 0K syz-executor0 180024 43745 0 0 0x4000000 1 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(bc9382705bad481e,ffffff0070edf1b0,ffff800000173290) at ip_fragment+0x625 ip_output(dca2956887e00c39,ffffff006f2fe578,ffffff006f05e700,0,ffffff006f05e700,ffffff006f2ffc00) at ip_output+0xc8d sys/netinet/ip_output.c:501 udp_output(7f298d059692d71,1112,ffffff006f2ffc00,0) at udp_output+0x45a sys/netinet/udp_usrreq.c:1004 sosend(7f298d059136e6e,ffffff0071817540,ffff80002111edd8,ffff80002111ef10,12ee,0) at sosend+0x477 sys/kern/uipc_socket.c:513 dofilewritev(1743673cfaa58b4d,0,7,ffff800021063c38,ffff80002111ef10) at dofilewritev+0x148 sys/kern/sys_generic.c:364 sys_writev(f831bc7f82599a8f,790,ffff800021063c38) at sys_writev+0xdb sys/kern/sys_generic.c:310 syscall(bc9382705b22a2f7) at syscall+0x473 mi_syscall sys/sys/syscall_mi.h:99 [inline] syscall(bc9382705b22a2f7) at syscall+0x473 sys/arch/amd64/amd64/trap.c:583 Xsyscall(6,0,d,0,3,68526a58010) at Xsyscall+0x128 end of kernel end trace frame: 0x6877b656aa0, 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{0}> ddb{0}> set $lines = 0 ddb{0}> show panic malformed IPv4 option passed to ip_optcopy ddb{0}> 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(bc9382705bad481e,ffffff0070edf1b0,ffff800000173290) at ip_fragment+0x625 ip_output(dca2956887e00c39,ffffff006f2fe578,ffffff006f05e700,0,ffffff006f05e700,ffffff006f2ffc00) at ip_output+0xc8d sys/netinet/ip_output.c:501 udp_output(7f298d059692d71,1112,ffffff006f2ffc00,0) at udp_output+0x45a sys/netinet/udp_usrreq.c:1004 sosend(7f298d059136e6e,ffffff0071817540,ffff80002111edd8,ffff80002111ef10,12ee,0) at sosend+0x477 sys/kern/uipc_socket.c:513 dofilewritev(1743673cfaa58b4d,0,7,ffff800021063c38,ffff80002111ef10) at dofilewritev+0x148 sys/kern/sys_generic.c:364 sys_writev(f831bc7f82599a8f,790,ffff800021063c38) at sys_writev+0xdb sys/kern/sys_generic.c:310 syscall(bc9382705b22a2f7) at syscall+0x473 mi_syscall sys/sys/syscall_mi.h:99 [inline] syscall(bc9382705b22a2f7) at syscall+0x473 sys/arch/amd64/amd64/trap.c:583 Xsyscall(6,0,d,0,3,68526a58010) at Xsyscall+0x128 end of kernel end trace frame: 0x6877b656aa0, count: -10 ddb{0}> show registers rdi 0xffffffff81efc250 kprintf_mutex rsi 0xffffffff818bdff7 db_enter+0x17 rbp 0xffff80002111ea00 rbx 0xffff80002111eaa0 rdx 0xffff800000ad9000 rcx 0x1531 __ALIGN_SIZE+0x531 rax 0xffff800000ad9000 r8 0xffff80002111e9d0 r9 0 r10 0xffff80002111e860 r11 0x6d0c790e53a471b2 r12 0x3000000008 r13 0xffff80002111ea10 r14 0x100 r15 0xffffffff81c5c0b4 substchar+0xf53a rip 0xffffffff818bdff8 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff80002111e9f0 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb{0}> show proc PROC (syz-executor0) pid=265534 stat=onproc flags process=0 proc=4000000 pri=85, usrpri=85, nice=20 forw=0xffffffffffffffff, list=0xffff800021063080,0xffff800021062988 process=0xffff800021064358 user=0xffff80002111a000, vmspace=0xffffff007f124d68 estcpu=35, cpticks=1, pctcpu=0.0 user=0, sys=1, intr=0 ddb{0}> ps PID TID PPID UID S FLAGS WAIT COMMAND 43745 411233 44392 0 2 0x80 syz-executor0 *43745 265534 44392 0 7 0x4000000 syz-executor0 43745 180024 44392 0 7 0x4000000 syz-executor0 15419 120113 1 0 3 0x100083 ttyin getty 463 456817 0 0 3 0x14200 bored sosplice 46173 80405 38241 0 2 0x482 syz-executor1 44392 322728 38241 0 3 0x82 nanosleep syz-executor0 38241 132077 65458 0 3 0x82 thrsleep syz-fuzzer 38241 479962 65458 0 2 0x4000482 syz-fuzzer 38241 291891 65458 0 3 0x4000082 thrsleep syz-fuzzer 38241 210132 65458 0 3 0x4000082 thrsleep syz-fuzzer 38241 267943 65458 0 3 0x4000082 thrsleep syz-fuzzer 38241 426700 65458 0 3 0x4000082 thrsleep syz-fuzzer 38241 450609 65458 0 3 0x4000082 thrsleep syz-fuzzer 38241 97977 65458 0 3 0x4000082 kqread syz-fuzzer 38241 35989 65458 0 3 0x4000082 thrsleep syz-fuzzer 38241 164843 65458 0 3 0x4000082 thrsleep syz-fuzzer 65458 181657 59615 0 3 0x10008a pause ksh 59615 425805 99876 0 3 0x92 select sshd 99876 239412 1 0 3 0x80 select sshd 58619 417516 46526 73 3 0x100090 kqread syslogd 46526 455971 1 0 3 0x100082 netio syslogd 88828 381630 1 77 3 0x100090 poll dhclient 73472 180979 1 0 3 0x80 poll dhclient 28387 448639 0 0 3 0x14200 pgzero zerothread 52220 213547 0 0 3 0x14200 aiodoned aiodoned 16759 268984 0 0 3 0x14200 syncer update 85407 320556 0 0 3 0x14200 cleaner cleaner 38910 121169 0 0 3 0x14200 reaper reaper 63854 245587 0 0 3 0x14200 pgdaemon pagedaemon 67891 8379 0 0 3 0x14200 bored crynlk 17407 304243 0 0 3 0x14200 bored crypto 52977 196805 0 0 3 0x40014200 acpi0 acpi0 68893 226415 0 0 3 0x40014200 idle1 65642 230398 0 0 3 0x14200 bored softnet 1724 118616 0 0 3 0x14200 bored systqmp 90094 138181 0 0 3 0x14200 bored systq 97167 248293 0 0 3 0x40014200 bored softclock 47352 296113 0 0 3 0x40014200 idle0 1 174235 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper