panic: m_copym0: short mbuf chain Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *458652 21295 0 0x12 0 0 sshd db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff823b21d8) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd805ba52900,1070,1dc,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac0320) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da6d7d8,9,fffffd805ba52500,0,0,ffff80001d7179d0) at tcp_usrreq+0xa54 sosend(fffffd805da6d7d8,0,ffff80001d71e898,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d7179d0,4,ffff80001d71e898,0,ffff80001d71e980) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d7179d0,ffff80001d71e930,ffff80001d71e980) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d71ea00) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffcb640, 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> set $maxwidth = 0 ddb> show panic m_copym0: short mbuf chain ddb> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff823b21d8) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd805ba52900,1070,1dc,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac0320) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da6d7d8,9,fffffd805ba52500,0,0,ffff80001d7179d0) at tcp_usrreq+0xa54 sosend(fffffd805da6d7d8,0,ffff80001d71e898,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d7179d0,4,ffff80001d71e898,0,ffff80001d71e980) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d7179d0,ffff80001d71e930,ffff80001d71e980) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d71ea00) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffcb640, count: -10 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff80001d71e360 rbx 0xffff80001d71e410 rdx 0x2 rcx 0 rax 0x1 r8 0xffffffff820c6cff kprintf+0x15f r9 0x1 r10 0x2 r11 0x66e273f69b28ac35 r12 0x3000000008 r13 0xffff80001d71e370 r14 0x100 r15 0x1 rip 0xffffffff819ec938 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff80001d71e350 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (sshd) pid=458652 stat=onproc flags process=12 proc=0 pri=24, usrpri=50, nice=20 forw=0xffffffffffffffff, list=0xffff80001d718870,0xffff80001d717290 process=0xffff8000ffff8e78 user=0xffff80001d719000, vmspace=0xfffffd806bc0a880 estcpu=0, cpticks=0, pctcpu=0.0 user=0, sys=0, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 56884 102458 1788 0 2 0 syz-executor.0 56884 225690 1788 0 2 0x4000000 syz-executor.0 1788 200258 5595 0 3 0x82 nanosleep syz-executor.0 49928 368285 0 0 3 0x14200 bored sosplice 56095 495680 5595 0 2 0x2 syz-executor.1 5595 355784 46267 0 2 0x2 syz-fuzzer 5595 30352 46267 0 3 0x4000082 nanosleep syz-fuzzer 5595 349702 46267 0 3 0x4000082 thrsleep syz-fuzzer 5595 371834 46267 0 3 0x4000082 thrsleep syz-fuzzer 5595 118030 46267 0 3 0x4000082 thrsleep syz-fuzzer 5595 392255 46267 0 3 0x4000082 thrsleep syz-fuzzer 5595 231496 46267 0 3 0x4000082 thrsleep syz-fuzzer 5595 20701 46267 0 3 0x4000082 thrsleep syz-fuzzer 46267 58240 21295 0 3 0x10008a pause ksh *21295 458652 43818 0 7 0x12 sshd 98604 70225 1 0 3 0x100083 ttyin getty 43818 433851 1 0 3 0x80 select sshd 20244 75862 99600 73 3 0x100090 kqread syslogd 99600 78661 1 0 3 0x100082 netio syslogd 70500 464603 1 77 3 0x100090 poll dhclient 67224 120461 1 0 3 0x80 poll dhclient 45767 89261 0 0 3 0x14200 bored smr 16475 396989 0 0 2 0x14200 zerothread 29738 53811 0 0 3 0x14200 aiodoned aiodoned 59705 99909 0 0 3 0x14200 syncer update 79994 341920 0 0 3 0x14200 cleaner cleaner 48357 106740 0 0 3 0x14200 reaper reaper 20047 96973 0 0 3 0x14200 pgdaemon pagedaemon 60899 491095 0 0 3 0x14200 bored crynlk 11555 134597 0 0 3 0x14200 bored crypto 272 318870 0 0 3 0x40014200 acpi0 acpi0 28107 388816 0 0 3 0x14200 bored softnet 20089 208712 0 0 3 0x14200 bored systqmp 32056 230948 0 0 3 0x14200 bored systq 64677 34551 0 0 3 0x40014200 bored softclock 28768 424744 0 0 3 0x40014200 idle0 1 395588 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 9503 6352K 6720K 78643K 10962 0 pcb 13 8K 8K 78643K 82 0 rtable 90 3K 7K 78643K 487 0 ifaddr 83 16K 17K 78643K 180 0 counters 21 16K 16K 78643K 23 0 ioctlops 0 0K 4K 78643K 78 0 iov 0 0K 16K 78643K 67 0 mount 1 1K 1K 78643K 1 0 vnodes 1223 77K 77K 78643K 1372 0 UFS quota 1 32K 32K 78643K 1 0 UFS mount 5 36K 36K 78643K 5 0 shm 2 1K 5K 78643K 5 0 VM map 2 0K 0K 78643K 2 0 sem 12 0K 0K 78643K 56 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1809 195K 288K 78643K 12938 0 file desc 5 13K 25K 78643K 307 0 sigio 0 0K 0K 78643K 4 0 proc 50 38K 63K 78643K 417 0 subproc 32 2K 2K 78643K 51 0 NFS srvsock 1 0K 0K 78643K 1 0 NFS daemon 1 16K 16K 78643K 1 0 ip_moptions 0 0K 0K 78643K 29 0 in_multi 73 3K 3K 78643K 126 0 ether_multi 1 0K 0K 78643K 12 0 ISOFS mount 1 32K 32K 78643K 1 0 MSDOSFS mount 1 16K 16K 78643K 1 0 ttys 49 228K 228K 78643K 49 0 exec 0 0K 1K 78643K 216 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 128 55K 56K 78643K 1589 0 UVM aobj 21 2K 2K 78643K 23 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 ip6_options 0 0K 0K 78643K 66 0 NDP 12 0K 0K 78643K 20 0 temp 102 3843K 3907K 78643K 3634 0 kqueue 3 4K 18K 78643K 30 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 8 0 2 1 0 1 1 0 8 0 rtpcb 80 33 0 31 1 0 1 1 0 8 0 rtentry 112 65 0 31 2 0 2 2 0 8 0 unpcb 120 141 0 133 1 0 1 1 0 8 0 syncache 264 6 0 6 2 1 1 1 0 8 1 tcpqe 32 44 0 44 1 1 0 1 0 8 0 tcpcb 544 160 0 156 1 0 1 1 0 8 0 ipq 40 2 0 2 1 1 0 1 0 8 0 ipqe 40 4 0 4 1 1 0 1 0 8 0 inpcb 280 409 0 402 2 0 2 2 0 8 1 nd6 48 9 0 5 1 0 1 1 0 8 0 ppxss 1128 1 0 1 1 1 0 1 0 8 0 pfstscr 40 2 0 1 1 0 1 1 0 8 0 pfrktable 1344 97 0 96 2 1 1 1 0 8 0 pftag 88 16 0 16 2 1 1 1 0 8 1 pfstitem 24 1 0 0 1 0 1 1 0 8 0 pfstkey 112 2 0 1 1 0 1 1 0 8 0 pfstate 328 2 0 1 1 0 1 1 0 8 0 pfrule 1360 22 0 16 2 1 1 1 0 8 0 art_heap8 4096 2 0 0 2 0 2 2 0 8 0 art_heap4 256 312 0 144 15 3 12 13 0 8 0 art_table 32 314 0 144 2 0 2 2 0 8 0 art_node 16 64 0 35 1 0 1 1 0 8 0 sysvmsgpl 40 8 0 4 1 0 1 1 0 8 0 semupl 112 1 0 1 1 1 0 1 0 8 0 semapl 112 54 0 44 1 0 1 1 0 8 0 shmpl 112 21 0 2 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 1792 0 394 88 0 88 88 0 8 0 ffsino 240 1792 0 394 83 0 83 83 0 8 0 nchpl 144 2538 0 950 60 0 60 60 0 8 0 uvmvnodes 72 1939 0 0 36 0 36 36 0 8 0 vnodes 208 1939 0 0 103 0 103 103 0 8 0 namei 1024 6801 0 6801 1 0 1 1 0 8 1 vcpupl 1984 2 0 0 1 0 1 1 0 8 0 vmpool 528 2 0 0 1 0 1 1 0 8 0 pfiaddrpl 120 26 0 26 2 1 1 1 0 8 1 scsiplug 64 1 0 1 1 1 0 1 0 8 0 scxspl 192 7184 0 7184 1 0 1 1 0 8 1 plimitpl 152 28 0 21 1 0 1 1 0 8 0 sigapl 424 491 0 462 4 0 4 4 0 8 0 futexpl 56 6319 0 6319 1 0 1 1 0 8 1 knotepl 112 99 0 80 1 0 1 1 0 8 0 kqueuepl 144 47 0 45 1 0 1 1 0 8 0 pipelkpl 16 108 0 98 1 0 1 1 0 8 0 pipepl 120 216 0 197 1 0 1 1 0 8 0 fdescpl 432 476 0 462 2 0 2 2 0 8 0 filepl 120 3122 0 3027 4 0 4 4 0 8 1 lockfpl 104 101 0 100 1 0 1 1 0 8 0 lockfspl 48 35 0 34 1 0 1 1 0 8 0 sessionpl 112 18 0 8 1 0 1 1 0 8 0 pgrppl 48 47 0 37 1 0 1 1 0 8 0 ucredpl 96 282 0 275 1 0 1 1 0 8 0 zombiepl 144 462 0 462 1 0 1 1 0 8 1 processpl 920 491 0 462 4 0 4 4 0 8 0 procpl 624 825 0 788 4 0 4 4 0 8 0 sosppl 128 10 0 10 1 0 1 1 0 8 1 sockpl 400 585 0 568 4 0 4 4 0 8 2 mcl64k 65536 541 0 541 66 15 51 65 0 8 51 mcl16k 16384 3 0 3 2 1 1 1 0 8 1 mcl12k 12288 9 0 9 1 0 1 1 0 8 1 mcl9k 9216 4 0 4 2 1 1 1 0 8 1 mcl8k 8192 11 0 11 2 1 1 1 0 8 1 mcl4k 4096 39 0 38 2 1 1 1 0 8 0 mcl2k2 2112 1 0 1 1 1 0 1 0 8 0 mcl2k 2048 74320 0 74272 16 9 7 13 0 8 0 mtagpl 80 37 0 11 2 1 1 1 0 8 0 mbufpl 256 120130 0 119987 43 24 19 42 0 8 8 bufpl 280 4056 0 125 281 0 281 281 0 8 0 anonpl 16 67375 0 52462 81 2 79 79 0 107 14 amapchunkpl 152 2665 0 2537 19 6 13 13 0 158 6 amappl16 192 2366 0 1479 57 4 53 57 0 8 8 amappl15 184 180 0 176 1 0 1 1 0 8 0 amappl14 176 103 0 99 1 0 1 1 0 8 0 amappl13 168 33 0 30 1 0 1 1 0 8 0 amappl12 160 7 0 7 2 2 0 1 0 8 0 amappl11 152 231 0 218 1 0 1 1 0 8 0 amappl10 144 21 0 14 1 0 1 1 0 8 0 amappl9 136 386 0 385 1 0 1 1 0 8 0 amappl8 128 349 0 307 2 0 2 2 0 8 0 amappl7 120 112 0 99 1 0 1 1 0 8 0 amappl6 112 152 0 144 1 0 1 1 0 8 0 amappl5 104 293 0 281 1 0 1 1 0 8 0 amappl4 96 565 0 535 1 0 1 1 0 8 0 amappl3 88 191 0 185 1 0 1 1 0 8 0 amappl2 80 2977 0 2910 2 0 2 2 0 8 0 amappl1 72 18256 0 17847 23 14 9 17 0 8 0 amappl 80 1072 0 1030 2 0 2 2 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 22 0 2 1 0 1 1 0 8 0 uaddrrnd 24 478 0 462 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 478 0 462 1 0 1 1 0 8 0 vmmpekpl 168 6930 0 6899 2 0 2 2 0 8 0 vmmpepl 168 63880 0 61905 134 13 121 121 0 357 33 vmsppl 272 477 0 462 3 1 2 2 0 8 0 pdppl 4096 962 0 926 6 1 5 6 0 8 0 pvpl 32 196372 0 178480 186 0 186 186 0 265 31 pmappl 200 477 0 462 1 0 1 1 0 8 0 extentpl 40 53 0 36 1 0 1 1 0 8 0 phpool 112 345 0 59 10 0 10 10 0 8 0 ddb> machine ddbcpu 0 No such command ddb> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff823b21d8) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd805ba52900,1070,1dc,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac0320) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da6d7d8,9,fffffd805ba52500,0,0,ffff80001d7179d0) at tcp_usrreq+0xa54 sosend(fffffd805da6d7d8,0,ffff80001d71e898,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d7179d0,4,ffff80001d71e898,0,ffff80001d71e980) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d7179d0,ffff80001d71e930,ffff80001d71e980) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d71ea00) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffcb640, count: -10 ddb> machine ddbcpu 1 No such command ddb> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff823b21d8) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd805ba52900,1070,1dc,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac0320) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da6d7d8,9,fffffd805ba52500,0,0,ffff80001d7179d0) at tcp_usrreq+0xa54 sosend(fffffd805da6d7d8,0,ffff80001d71e898,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d7179d0,4,ffff80001d71e898,0,ffff80001d71e980) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d7179d0,ffff80001d71e930,ffff80001d71e980) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d71ea00) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffcb640, count: -10