panic: malformed IPv4 option passed to ip_optcopy Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *104945 23413 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(a91d71f4ba7e642e,ffffff00355c0f00,ffff800000171290) at ip_fragment+0x551 ip_output(9e377df32c71ef24,ffffff00355c0700,ffffff00355c0700,0,ffffff00370d39d8,ffffff00364ffd88) at ip_output+0xc06 sys/netinet/ip_output.c:501 udp_output(4b9fa645e9f0740d,1199,ffffff00364ffd88,0) at udp_output+0x444 sys/netinet/udp_usrreq.c:1004 sosend(1caa1184413277c4,ffffff0038d7f1e8,ffff800014a64398,1267,ffff800014a644d0,0) at sosend+0x472 sys/kern/uipc_socket.c:513 dofilewritev(f93b87422822ad9d,0,8,ffff8000ffff92c8,ffff800014a644d0) at dofilewritev+0x14b sys/kern/sys_generic.c:364 sys_writev(7094332d5ce18490,ffff800014a64570,ffff8000ffff92c8) at sys_writev+0xdb sys/kern/sys_generic.c:310 syscall(b94104a0f3a53267) at syscall+0x3f1 Xsyscall(6,0,d,0,3,440be96d010) at Xsyscall+0x128 end of kernel end trace frame: 0x44357f3f5f0, 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(a91d71f4ba7e642e,ffffff00355c0f00,ffff800000171290) at ip_fragment+0x551 ip_output(9e377df32c71ef24,ffffff00355c0700,ffffff00355c0700,0,ffffff00370d39d8,ffffff00364ffd88) at ip_output+0xc06 sys/netinet/ip_output.c:501 udp_output(4b9fa645e9f0740d,1199,ffffff00364ffd88,0) at udp_output+0x444 sys/netinet/udp_usrreq.c:1004 sosend(1caa1184413277c4,ffffff0038d7f1e8,ffff800014a64398,1267,ffff800014a644d0,0) at sosend+0x472 sys/kern/uipc_socket.c:513 dofilewritev(f93b87422822ad9d,0,8,ffff8000ffff92c8,ffff800014a644d0) at dofilewritev+0x14b sys/kern/sys_generic.c:364 sys_writev(7094332d5ce18490,ffff800014a64570,ffff8000ffff92c8) at sys_writev+0xdb sys/kern/sys_generic.c:310 syscall(b94104a0f3a53267) at syscall+0x3f1 Xsyscall(6,0,d,0,3,440be96d010) at Xsyscall+0x128 end of kernel end trace frame: 0x44357f3f5f0, count: -10 ddb> show registers rdi 0xffffffff81eecb18 kprintf_mutex rsi 0xffffffff81230e27 db_enter+0x17 rbp 0xffff800014a63fc0 rbx 0xffff800014a64060 rdx 0xffff800000932000 rcx 0x1728 __ALIGN_SIZE+0x728 rax 0xffff800000932000 r8 0xffff800014a63f90 r9 0 r10 0xd12432d05833031c r11 0xd3a27eed0adba6fe r12 0x3000000008 r13 0xffff800014a63fd0 r14 0x100 r15 0xffffffff81cba6f5 apollo_udma100_tim+0xc629 rip 0xffffffff81230e28 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff800014a63fb0 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (syz-executor0) pid=104945 stat=onproc flags process=0 proc=4000000 pri=73, usrpri=73, nice=20 forw=0xffffffffffffffff, list=0xffff8000ffff9520,0xffffffff81f9f800 process=0xffff8000ffff5a60 user=0xffff800014a5f000, vmspace=0xffffff003f12a528 estcpu=36, cpticks=0, pctcpu=0.0 user=0, sys=0, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 23413 110588 61192 0 2 0 syz-executor0 *23413 104945 61192 0 7 0x4000000 syz-executor0 93321 458050 1 0 3 0x100083 ttyin getty 24555 205671 0 0 3 0x14200 bored sosplice 61192 333091 91587 0 3 0x82 nanosleep syz-executor0 27556 135283 91587 0 2 0x2 syz-executor1 91587 484602 2124 0 3 0x82 thrsleep syz-fuzzer 91587 130001 2124 0 3 0x4000082 nanosleep syz-fuzzer 91587 395779 2124 0 3 0x4000082 thrsleep syz-fuzzer 91587 137765 2124 0 3 0x4000082 thrsleep syz-fuzzer 91587 35477 2124 0 3 0x4000082 kqread syz-fuzzer 91587 388535 2124 0 3 0x4000082 thrsleep syz-fuzzer 91587 241264 2124 0 3 0x4000082 thrsleep syz-fuzzer 2124 357038 10670 0 3 0x10008a pause ksh 10670 208701 84047 0 3 0x92 select sshd 84047 241109 1 0 3 0x80 select sshd 76425 338194 95512 73 3 0x100090 kqread syslogd 95512 2267 1 0 3 0x100082 netio syslogd 47855 261320 1 77 3 0x100090 poll dhclient 41882 261609 1 0 3 0x80 poll dhclient 69999 397672 0 0 2 0x14200 zerothread 25518 492651 0 0 3 0x14200 aiodoned aiodoned 37722 290947 0 0 3 0x14200 syncer update 2765 353005 0 0 3 0x14200 cleaner cleaner 51557 188554 0 0 3 0x14200 reaper reaper 85102 73361 0 0 3 0x14200 pgdaemon pagedaemon 26471 171132 0 0 3 0x14200 bored crynlk 41077 236047 0 0 3 0x14200 bored crypto 12629 93729 0 0 3 0x40014200 acpi0 acpi0 1046 413167 0 0 3 0x14200 bored softnet 98421 18789 0 0 3 0x14200 bored systqmp 59960 386700 0 0 3 0x14200 bored systq 55958 299823 0 0 3 0x40014200 bored softclock 41497 254201 0 0 3 0x40014200 idle0 1 471695 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper