panic: m_copym0: short mbuf chain Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *319696 52780 0 0x12 0 0 sshd db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff823c7279) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8069ce1200,2a4,124,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac2980) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da69008,9,fffffd8069ce1100,0,0,ffff80001d717010) at tcp_usrreq+0xa54 sosend(fffffd805da69008,0,ffff80001d6ca018,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:555 dofilewritev(ffff80001d717010,4,ffff80001d6ca018,0,ffff80001d6ca100) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d717010,ffff80001d6ca0b0,ffff80001d6ca100) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d6ca180) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffc5c60, 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(ffffffff823c7279) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8069ce1200,2a4,124,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac2980) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da69008,9,fffffd8069ce1100,0,0,ffff80001d717010) at tcp_usrreq+0xa54 sosend(fffffd805da69008,0,ffff80001d6ca018,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:555 dofilewritev(ffff80001d717010,4,ffff80001d6ca018,0,ffff80001d6ca100) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d717010,ffff80001d6ca0b0,ffff80001d6ca100) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d6ca180) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffc5c60, count: -10 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff80001d6c9ae0 rbx 0xffff80001d6c9b90 rdx 0x2 rcx 0 rax 0x1 r8 0xffffffff8203df2f kprintf+0x15f r9 0x1 r10 0x2 r11 0x561129b1dd109aca r12 0x3000000008 r13 0xffff80001d6c9af0 r14 0x100 r15 0x1 rip 0xffffffff81fb0608 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff80001d6c9ad0 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (sshd) pid=319696 stat=onproc flags process=12 proc=0 pri=24, usrpri=50, nice=20 forw=0xffffffffffffffff, list=0xffff80001d718ae0,0xffff80001d717770 process=0xffff8000ffff8e78 user=0xffff80001d6c5000, vmspace=0xfffffd806bc09770 estcpu=0, cpticks=0, pctcpu=0.0 user=0, sys=0, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 79535 249176 0 0 3 0x14280 nfsidl nfsio 78582 251816 0 0 3 0x14280 nfsidl nfsio 55543 202581 0 0 3 0x14280 nfsidl nfsio 46491 87743 0 0 3 0x14280 nfsidl nfsio 98030 235733 0 0 3 0x14280 nfsidl nfsio 29495 183297 0 0 3 0x14280 nfsidl nfsio 99647 442661 0 0 3 0x14280 nfsidl nfsio 90712 290310 0 0 3 0x14280 nfsidl nfsio 59278 19918 0 0 3 0x14280 nfsidl nfsio 28786 419795 0 0 3 0x14280 nfsidl nfsio 28014 73360 0 0 3 0x14280 nfsidl nfsio 58555 196018 0 0 3 0x14280 nfsidl nfsio 64454 409862 0 0 3 0x14280 nfsidl nfsio 23161 318430 0 0 3 0x14280 nfsidl nfsio 96512 1397 0 0 3 0x14280 nfsidl nfsio 48312 342455 0 0 3 0x14280 nfsidl nfsio 74423 238701 0 0 3 0x14280 nfsidl nfsio 5845 48255 0 0 3 0x14280 nfsidl nfsio 90709 252727 0 0 3 0x14280 nfsidl nfsio 25870 74764 0 0 3 0x14280 nfsidl nfsio 77891 51319 0 0 3 0x14200 acct acct 57691 519397 0 0 3 0x14200 bored sosplice 59432 402824 78100 0 2 0x2 syz-executor.0 51984 16739 78100 0 2 0x2 syz-executor.1 78100 77096 92724 0 3 0x82 thrsleep syz-fuzzer 78100 8836 92724 0 2 0x4000002 syz-fuzzer 78100 120416 92724 0 3 0x4000082 thrsleep syz-fuzzer 78100 414326 92724 0 3 0x4000082 thrsleep syz-fuzzer 78100 25917 92724 0 3 0x4000082 thrsleep syz-fuzzer 78100 276035 92724 0 2 0x4000002 syz-fuzzer 78100 429339 92724 0 3 0x4000082 thrsleep syz-fuzzer 92724 414785 52780 0 3 0x10008a pause ksh *52780 319696 27754 0 7 0x12 sshd 42778 78032 1 0 3 0x100083 ttyin getty 27754 220314 1 0 3 0x80 select sshd 19488 33158 29717 73 3 0x100090 kqread syslogd 29717 84026 1 0 3 0x100082 netio syslogd 6842 374049 1 77 3 0x100090 poll dhclient 17517 245638 1 0 3 0x80 poll dhclient 48664 382873 0 0 3 0x14200 bored smr 81000 276063 0 0 3 0x14200 pgzero zerothread 67334 245800 0 0 3 0x14200 aiodoned aiodoned 38446 174795 0 0 3 0x14200 syncer update 982 44806 0 0 3 0x14200 cleaner cleaner 43130 136009 0 0 3 0x14200 reaper reaper 87446 412115 0 0 3 0x14200 pgdaemon pagedaemon 27338 337009 0 0 3 0x14200 bored crynlk 20880 400963 0 0 3 0x14200 bored crypto 80151 69086 0 0 3 0x40014200 acpi0 acpi0 55378 197611 0 0 3 0x14200 bored softnet 4985 205351 0 0 3 0x14200 bored systqmp 10455 85629 0 0 3 0x14200 bored systq 11800 468462 0 0 3 0x40014200 bored softclock 87714 31162 0 0 3 0x40014200 idle0 1 270462 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 9490 6340K 6858K 78643K 11186 0 pcb 13 8K 8K 78643K 55 0 rtable 112 5K 6K 78643K 332 0 ifaddr 69 14K 14K 78643K 114 0 counters 21 16K 16K 78643K 23 0 ioctlops 0 0K 4K 78643K 73 0 iov 0 0K 16K 78643K 44 0 mount 1 1K 1K 78643K 1 0 vnodes 1220 77K 77K 78643K 1411 0 UFS quota 1 32K 32K 78643K 1 0 UFS mount 5 36K 36K 78643K 5 0 shm 2 1K 5K 78643K 6 0 VM map 2 0K 0K 78643K 2 0 sem 12 0K 1K 78643K 71 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1809 195K 288K 78643K 12938 0 file desc 4 9K 25K 78643K 287 0 proc 49 38K 54K 78643K 370 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 17 0 in_multi 42 2K 2K 78643K 79 0 ether_multi 1 0K 0K 78643K 6 0 mrt 0 0K 0K 78643K 3 0 ISOFS mount 1 32K 32K 78643K 1 0 MSDOSFS mount 1 16K 16K 78643K 1 0 ttys 55 254K 254K 78643K 55 0 exec 0 0K 1K 78643K 207 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 130 88K 88K 78643K 1512 0 UVM aobj 17 2K 2K 78643K 28 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 ip6_options 0 0K 0K 78643K 24 0 NDP 10 0K 0K 78643K 19 0 temp 102 3861K 3925K 78643K 3758 0 kqueue 3 4K 18K 78643K 25 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 7 0 0 1 0 1 1 0 8 0 rtpcb 80 59 0 57 1 0 1 1 0 8 0 rtentry 112 55 0 13 2 0 2 2 0 8 0 unpcb 120 155 0 147 1 0 1 1 0 8 0 syncache 264 4 0 4 1 1 0 1 0 8 0 tcpqe 32 29 0 29 1 1 0 1 0 8 0 tcpcb 544 79 0 75 1 0 1 1 0 8 0 inpcb 296 436 0 429 2 0 2 2 0 8 1 rttmr 72 1 0 1 1 1 0 1 0 8 0 nd6 48 11 0 7 1 0 1 1 0 8 0 swfcl 56 2 0 0 1 0 1 1 0 8 0 pfstscr 40 2 0 0 1 0 1 1 0 8 0 pfrke_plain 160 2 0 0 1 0 1 1 0 8 0 pfrktable 1344 37 0 32 1 0 1 1 0 8 0 pftag 88 12 0 10 1 0 1 1 0 8 0 pfstitem 24 2 0 0 1 0 1 1 0 8 0 pfstkey 112 2 0 0 1 0 1 1 0 8 0 pfstate 328 1 0 0 1 0 1 1 0 8 0 pfrule 1360 14 0 12 1 0 1 1 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 214 0 40 13 0 13 13 0 8 0 art_table 32 215 0 40 2 0 2 2 0 8 0 art_node 16 54 0 15 1 0 1 1 0 8 0 sysvmsgpl 40 4 0 0 1 0 1 1 0 8 0 semupl 112 1 0 1 1 1 0 1 0 8 0 semapl 112 67 0 57 1 0 1 1 0 8 0 shmpl 112 26 0 11 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 1789 0 390 88 0 88 88 0 8 0 ffsino 240 1789 0 390 83 0 83 83 0 8 0 nchpl 144 2357 0 755 60 0 60 60 0 8 0 rtmask 32 4 0 2 1 0 1 1 0 8 0 uvmvnodes 72 1966 0 0 36 0 36 36 0 8 0 vnodes 208 1966 0 0 104 0 104 104 0 8 0 namei 1024 6305 0 6305 1 0 1 1 0 8 1 vcpupl 1984 8 0 0 1 0 1 1 0 8 0 vmpool 528 10 0 2 1 0 1 1 0 8 0 pfiaddrpl 120 12 0 8 1 0 1 1 0 8 0 scxspl 192 6940 0 6940 1 0 1 1 0 8 1 plimitpl 152 36 0 29 1 0 1 1 0 8 0 sigapl 424 495 0 446 6 0 6 6 0 8 0 futexpl 56 5717 0 5717 1 0 1 1 0 8 1 knotepl 112 85 0 66 1 0 1 1 0 8 0 kqueuepl 144 54 0 52 1 0 1 1 0 8 0 pipelkpl 16 114 0 104 1 0 1 1 0 8 0 pipepl 120 228 0 209 2 1 1 2 0 8 0 fdescpl 432 459 0 446 2 0 2 2 0 8 0 filepl 120 2837 0 2742 4 0 4 4 0 8 1 lockfpl 104 58 0 57 1 0 1 1 0 8 0 lockfspl 48 22 0 21 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 96 273 0 266 1 0 1 1 0 8 0 zombiepl 144 446 0 446 1 0 1 1 0 8 1 processpl 920 495 0 446 7 0 7 7 0 8 0 procpl 624 811 0 756 5 0 5 5 0 8 0 sosppl 128 6 0 6 1 0 1 1 0 8 1 sockpl 400 650 0 633 4 1 3 4 0 8 1 mcl64k 65536 25 0 25 1 0 1 1 0 8 1 mcl16k 16384 2 0 2 1 1 0 1 0 8 0 mcl12k 12288 6 0 6 1 0 1 1 0 8 1 mcl9k 9216 5 0 5 1 0 1 1 0 8 1 mcl8k 8192 7 0 7 1 0 1 1 0 8 1 mcl4k 4096 36 0 36 1 0 1 1 0 8 1 mcl2k2 2112 5 0 5 1 0 1 1 0 8 1 mcl2k 2048 72330 0 72288 13 7 6 12 0 8 0 mtagpl 96 41 0 2 2 1 1 1 0 8 0 mbufpl 256 117174 0 116994 21 3 18 18 0 8 5 bufpl 280 3910 0 128 271 0 271 271 0 8 0 anonpl 16 60302 0 44405 83 2 81 81 0 107 12 amapchunkpl 152 2057 0 1926 15 3 12 13 0 158 6 amappl16 192 2341 0 1422 59 5 54 59 0 8 7 amappl15 184 4 0 1 1 0 1 1 0 8 0 amappl14 176 26 0 22 1 0 1 1 0 8 0 amappl13 168 26 0 23 1 0 1 1 0 8 0 amappl12 160 19 0 17 2 1 1 1 0 8 0 amappl11 152 300 0 289 1 0 1 1 0 8 0 amappl10 144 18 0 12 1 0 1 1 0 8 0 amappl9 136 376 0 374 1 0 1 1 0 8 0 amappl8 128 327 0 285 2 0 2 2 0 8 0 amappl7 120 106 0 94 1 0 1 1 0 8 0 amappl6 112 275 0 270 1 0 1 1 0 8 0 amappl5 104 396 0 386 1 0 1 1 0 8 0 amappl4 96 427 0 396 1 0 1 1 0 8 0 amappl3 88 112 0 107 1 0 1 1 0 8 0 amappl2 80 2848 0 2789 2 0 2 2 0 8 0 amappl1 72 17620 0 17218 24 15 9 17 0 8 0 amappl 80 1022 0 978 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 27 0 11 1 0 1 1 0 8 0 uaddrrnd 24 469 0 448 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 469 0 448 1 0 1 1 0 8 0 vmmpekpl 168 6767 0 6733 2 0 2 2 0 8 0 vmmpepl 168 60795 0 58878 117 14 103 111 0 357 12 vmsppl 272 468 0 448 2 0 2 2 0 8 0 pdppl 4096 944 0 904 7 1 6 6 0 8 0 pvpl 32 184848 0 165944 190 0 190 190 0 265 30 pmappl 200 468 0 448 2 0 2 2 0 8 0 extentpl 40 53 0 36 1 0 1 1 0 8 0 phpool 112 249 0 15 7 0 7 7 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(ffffffff823c7279) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8069ce1200,2a4,124,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac2980) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da69008,9,fffffd8069ce1100,0,0,ffff80001d717010) at tcp_usrreq+0xa54 sosend(fffffd805da69008,0,ffff80001d6ca018,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:555 dofilewritev(ffff80001d717010,4,ffff80001d6ca018,0,ffff80001d6ca100) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d717010,ffff80001d6ca0b0,ffff80001d6ca100) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d6ca180) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffc5c60, 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(ffffffff823c7279) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8069ce1200,2a4,124,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac2980) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da69008,9,fffffd8069ce1100,0,0,ffff80001d717010) at tcp_usrreq+0xa54 sosend(fffffd805da69008,0,ffff80001d6ca018,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:555 dofilewritev(ffff80001d717010,4,ffff80001d6ca018,0,ffff80001d6ca100) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d717010,ffff80001d6ca0b0,ffff80001d6ca100) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d6ca180) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffc5c60, count: -10