panic(ffffffff821be581) at panic+0x15c sys/kern/subr_prf.c:207 tcp_output(ffff8000009eeee0) at tcp_output+0x2ac0 tcp_setpersist sys/netinet/tcp_output.c:1130 [inline] tcp_output(ffff8000009eeee0) at tcp_output+0x2ac0 sys/netinet/tcp_output.c:333 tcp_usrreq(fffffd805da75198,9,fffffd805c82d900,0,0,ffff80001d3b7010) at tcp_usrreq+0xa54 sosend(fffffd805da75198,0,ffff80001d36c358,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d3b7010,4,ffff80001d36c358,0,ffff80001d36c440) at dofilewritev+0x1ab sys/kern/sys_generic.c:364 sys_write(ffff80001d3b7010,ffff80001d36c3f0,ffff80001d36c440) at sys_write+0x83 sys/kern/sys_generic.c:284 syscall(ffff80001d36c4c0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffd3ee0, 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. ddb> ddb> set $lines = 0 ddb> set $maxwidth = 0 ddb> show panic tcp_output: template len != hdrlen - optlen ddb> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff821be581) at panic+0x15c sys/kern/subr_prf.c:207 tcp_output(ffff8000009eeee0) at tcp_output+0x2ac0 tcp_setpersist sys/netinet/tcp_output.c:1130 [inline] tcp_output(ffff8000009eeee0) at tcp_output+0x2ac0 sys/netinet/tcp_output.c:333 tcp_usrreq(fffffd805da75198,9,fffffd805c82d900,0,0,ffff80001d3b7010) at tcp_usrreq+0xa54 sosend(fffffd805da75198,0,ffff80001d36c358,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d3b7010,4,ffff80001d36c358,0,ffff80001d36c440) at dofilewritev+0x1ab sys/kern/sys_generic.c:364 sys_write(ffff80001d3b7010,ffff80001d36c3f0,ffff80001d36c440) at sys_write+0x83 sys/kern/sys_generic.c:284 syscall(ffff80001d36c4c0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffd3ee0, count: -9 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff80001d36bec0 rbx 0xffff80001d36bf70 rdx 0x2 rcx 0 rax 0 r8 0xffff80001d36be80 r9 0x1 r10 0 r11 0xa2d6cc9cdb0f2ff6 r12 0x3000000008 r13 0xffff80001d36bed0 r14 0x100 r15 0x1 rip 0xffffffff81657178 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff80001d36beb0 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (sshd) pid=412565 stat=onproc flags process=12 proc=0 pri=24, usrpri=52, nice=20 forw=0xffffffffffffffff, list=0xffff80001d3b8870,0xffff80001d3b7500 process=0xffff80001d39f880 user=0xffff80001d367000, vmspace=0xfffffd806bc0a110 estcpu=2, cpticks=8, pctcpu=0.0 user=0, sys=8, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 4094 382751 73151 0 2 0 syz-executor.0 4094 216254 73151 0 2 0x4000000 syz-executor.0 36833 477002 17728 0 2 0x2 syz-executor.1 73151 98623 17728 0 2 0x482 syz-executor.0 17728 287178 52511 0 3 0x82 thrsleep syz-fuzzer 17728 345659 52511 0 2 0x4000482 syz-fuzzer 17728 75362 52511 0 2 0x4000482 syz-fuzzer 17728 378828 52511 0 3 0x4000082 thrsleep syz-fuzzer 17728 60373 52511 0 3 0x4000082 thrsleep syz-fuzzer 17728 63016 52511 0 2 0x4000002 syz-fuzzer 17728 348889 52511 0 3 0x4000082 thrsleep syz-fuzzer 52511 348058 13378 0 3 0x10008a pause ksh *13378 412565 74148 0 7 0x12 sshd 3478 286923 1 0 3 0x100083 ttyin getty 74148 244116 1 0 3 0x80 select sshd 6162 79490 37814 73 3 0x100090 kqread syslogd 37814 10590 1 0 3 0x100082 netio syslogd 26793 382364 1 77 3 0x100090 poll dhclient 61054 257412 1 0 3 0x80 poll dhclient 85024 268116 0 0 2 0x14200 zerothread 76848 139998 0 0 3 0x14200 aiodoned aiodoned 80449 462553 0 0 3 0x14200 syncer update 23392 101333 0 0 3 0x14200 cleaner cleaner 79090 456604 0 0 3 0x14200 reaper reaper 44355 253081 0 0 3 0x14200 pgdaemon pagedaemon 51771 431456 0 0 3 0x14200 bored crynlk 17253 514731 0 0 3 0x14200 bored crypto 81095 351637 0 0 3 0x40014200 acpi0 acpi0 91662 333741 0 0 3 0x14200 bored softnet 35889 168581 0 0 3 0x14200 bored systqmp 56621 52498 0 0 3 0x14200 bored systq 46343 167933 0 0 2 0x40014200 softclock 69355 337898 0 0 3 0x40014200 idle0 809 15442 0 0 2 0x14200 smr 1 405801 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb> show all locks No such command ddb> show malloc Type InUse MemUse HighUse Limit Requests Type Lim devbuf 9460 6453K 6453K 78643K 10560 0 pcb 13 8K 8K 78643K 23 0 rtable 105 3K 3K 78643K 189 0 ifaddr 39 10K 10K 78643K 41 0 counters 21 16K 16K 78643K 21 0 ioctlops 0 0K 2K 78643K 17 0 iov 0 0K 0K 78643K 2 0 mount 1 1K 1K 78643K 1 0 vnodes 1217 76K 76K 78643K 1227 0 UFS quota 1 32K 32K 78643K 1 0 UFS mount 5 36K 36K 78643K 5 0 shm 2 1K 5K 78643K 3 0 VM map 2 0K 0K 78643K 2 0 sem 2 0K 0K 78643K 2 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1794 195K 288K 78643K 12646 0 file desc 5 13K 25K 78643K 47 0 proc 47 38K 63K 78643K 365 0 subproc 32 2K 2K 78643K 34 0 NFS srvsock 1 0K 0K 78643K 1 0 NFS daemon 1 16K 16K 78643K 1 0 ip_moptions 0 0K 0K 78643K 2 0 in_multi 33 2K 2K 78643K 36 0 ether_multi 1 0K 0K 78643K 2 0 ISOFS mount 1 32K 32K 78643K 1 0 MSDOSFS mount 1 16K 16K 78643K 1 0 ttys 43 201K 201K 78643K 43 0 exec 0 0K 1K 78643K 183 0 pagedep 1 8K 8K 78643K 1 0 inodedep 1 32K 32K 78643K 1 0 newblk 1 0K 0K 78643K 1 0 VM swap 7 26K 26K 78643K 7 0 UVM amap 102 21K 22K 78643K 941 0 UVM aobj 4 2K 2K 78643K 4 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 ip6_options 0 0K 0K 78643K 4 0 NDP 5 0K 0K 78643K 9 0 temp 61 3003K 3067K 78643K 1853 0 kqueue 3 4K 4K 78643K 3 0 SYN cache 2 16K 16K 78643K 2 0 ddb> show all pools Name Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle arp 64 6 0 0 1 0 1 1 0 8 0 rtpcb 80 19 0 17 1 0 1 1 0 8 0 rtentry 112 45 0 1 2 0 2 2 0 8 0 unpcb 120 29 0 21 1 0 1 1 0 8 0 syncache 264 4 0 4 1 1 0 1 0 8 0 tcpqe 32 336 0 336 1 0 1 1 0 8 1 tcpcb 544 20 0 16 1 0 1 1 0 8 0 inpcb 280 56 0 49 1 0 1 1 0 8 0 nd6 48 4 0 0 1 0 1 1 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 212 0 0 14 0 14 14 0 8 0 art_table 32 213 0 0 2 0 2 2 0 8 0 art_node 16 44 0 4 1 0 1 1 0 8 0 shmpl 112 2 0 0 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino1pl 128 1436 0 36 46 0 46 46 0 8 0 ffsino 240 1436 0 36 83 0 83 83 0 8 0 nchpl 144 1683 0 73 60 0 60 60 0 8 0 uvmvnodes 72 1482 0 0 27 0 27 27 0 8 0 vnodes 208 1482 0 0 78 0 78 78 0 8 0 namei 1024 4113 0 4113 2 1 1 1 0 8 1 scxspl 192 4892 0 4892 1 0 1 1 0 8 1 plimitpl 152 14 0 7 1 0 1 1 0 8 0 sigapl 432 218 0 205 2 0 2 2 0 8 0 futexpl 56 409 0 409 1 0 1 1 0 8 1 knotepl 112 53 0 34 1 0 1 1 0 8 0 kqueuepl 104 4 0 2 1 0 1 1 0 8 0 pipelkpl 16 83 0 73 1 0 1 1 0 8 0 pipepl 120 166 0 147 1 0 1 1 0 8 0 fdescpl 432 219 0 205 2 0 2 2 0 8 0 filepl 120 1192 0 1097 4 0 4 4 0 8 1 lockfpl 104 5 0 4 1 0 1 1 0 8 0 lockfspl 48 3 0 2 1 0 1 1 0 8 0 sessionpl 112 17 0 7 1 0 1 1 0 8 0 pgrppl 48 17 0 7 1 0 1 1 0 8 0 ucredpl 96 82 0 75 1 0 1 1 0 8 0 zombiepl 144 205 0 205 2 1 1 1 0 8 1 processpl 896 233 0 205 4 0 4 4 0 8 0 procpl 624 255 0 220 3 0 3 3 0 8 0 sockpl 400 104 0 87 3 0 3 3 0 8 1 mcl64k 65536 2 0 2 1 0 1 1 0 8 1 mcl16k 16384 1 0 1 1 0 1 1 0 8 1 mcl8k 8192 2 0 2 1 0 1 1 0 8 1 mcl4k 4096 8 0 8 1 1 0 1 0 8 0 mcl2k 2048 61710 0 61644 21 4 17 18 0 8 7 mtagpl 80 6 0 2 2 1 1 1 0 8 0 mbufpl 256 98073 0 97905 13 2 11 11 0 8 0 bufpl 280 4043 0 179 276 0 276 276 0 8 0 anonpl 16 36665 0 21472 63 1 62 62 0 107 0 amapchunkpl 152 910 0 779 7 0 7 7 0 158 1 amappl16 192 933 0 105 42 0 42 42 0 8 0 amappl15 184 51 0 47 1 0 1 1 0 8 0 amappl14 176 33 0 29 1 0 1 1 0 8 0 amappl12 160 7 0 7 1 1 0 1 0 8 0 amappl11 152 51 0 39 1 0 1 1 0 8 0 amappl10 144 14 0 11 1 0 1 1 0 8 0 amappl9 136 563 0 560 1 0 1 1 0 8 0 amappl8 128 113 0 92 1 0 1 1 0 8 0 amappl7 120 91 0 80 1 0 1 1 0 8 0 amappl6 112 61 0 54 1 0 1 1 0 8 0 amappl5 104 134 0 124 1 0 1 1 0 8 0 amappl4 96 430 0 402 1 0 1 1 0 8 0 amappl3 88 119 0 111 1 0 1 1 0 8 0 amappl2 80 961 0 890 3 1 2 3 0 8 0 amappl1 72 13843 0 13421 26 16 10 20 0 8 0 amappl 80 477 0 437 1 0 1 1 0 84 0 dma4096 4096 1 0 1 1 1 0 1 0 8 0 dma256 256 6 0 6 1 1 0 1 0 8 0 dma128 128 253 0 253 1 1 0 1 0 8 0 dma64 64 6 0 6 1 1 0 1 0 8 0 dma32 32 7 0 7 1 1 0 1 0 8 0 dma16 16 18 0 17 1 0 1 1 0 8 0 aobjpl 64 3 0 0 1 0 1 1 0 8 0 uaddrrnd 24 219 0 205 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 219 0 205 1 0 1 1 0 8 0 vmmpekpl 168 5711 0 5684 2 0 2 2 0 8 0 vmmpepl 168 34137 0 32219 127 11 116 116 0 357 32 vmsppl 272 218 0 205 2 0 2 2 0 8 1 pdppl 4096 444 0 410 6 0 6 6 0 8 1 pvpl 32 125195 0 107043 155 4 151 151 0 265 2 pmappl 200 218 0 205 1 0 1 1 0 8 0 extentpl 40 46 0 29 1 0 1 1 0 8 0 phpool 112 158 0 10 5 0 5 5 0 8 0