panic: m_copym0: short mbuf chain Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *140383 82888 0 0x12 0 0 sshd db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff823cd2af) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd805c546c00,214,f4,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac3320) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da607d8,9,fffffd805c546b00,0,0,ffff80001d71d390) at tcp_usrreq+0xa54 sosend(fffffd805da607d8,0,ffff80001d6cd918,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:555 dofilewritev(ffff80001d71d390,4,ffff80001d6cd918,0,ffff80001d6cda00) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d71d390,ffff80001d6cd9b0,ffff80001d6cda00) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d6cda80) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffe45b0, 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(ffffffff823cd2af) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd805c546c00,214,f4,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac3320) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da607d8,9,fffffd805c546b00,0,0,ffff80001d71d390) at tcp_usrreq+0xa54 sosend(fffffd805da607d8,0,ffff80001d6cd918,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:555 dofilewritev(ffff80001d71d390,4,ffff80001d6cd918,0,ffff80001d6cda00) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d71d390,ffff80001d6cd9b0,ffff80001d6cda00) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d6cda80) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffe45b0, count: -10 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff80001d6cd3e0 rbx 0xffff80001d6cd490 rdx 0x2 rcx 0 rax 0x1 r8 0xffffffff8228533f kprintf+0x15f r9 0x1 r10 0x2 r11 0x22ea4c405027b0e2 r12 0x3000000008 r13 0xffff80001d6cd3f0 r14 0x100 r15 0x1 rip 0xffffffff81cfcf18 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff80001d6cd3d0 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (sshd) pid=140383 stat=onproc flags process=12 proc=0 pri=24, usrpri=50, nice=20 forw=0xffffffffffffffff, list=0xffff80001d71dae0,0xffff80001d71c500 process=0xffff80001d706018 user=0xffff80001d6c8000, vmspace=0xfffffd806bc09aa0 estcpu=0, cpticks=0, pctcpu=0.0 user=0, sys=0, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 43688 393945 0 0 3 0x14280 nfsidl nfsio 42667 64664 0 0 3 0x14280 nfsidl nfsio 71359 398128 0 0 3 0x14280 nfsidl nfsio 25775 11838 0 0 3 0x14280 nfsidl nfsio 12303 383047 0 0 3 0x14280 nfsidl nfsio 93134 107284 0 0 3 0x14280 nfsidl nfsio 97326 52570 0 0 3 0x14280 nfsidl nfsio 7571 348347 0 0 3 0x14280 nfsidl nfsio 30332 117243 0 0 3 0x14280 nfsidl nfsio 21230 252180 0 0 3 0x14280 nfsidl nfsio 94927 261083 0 0 3 0x14280 nfsidl nfsio 82207 169660 0 0 3 0x14280 nfsidl nfsio 93614 392854 0 0 3 0x14280 nfsidl nfsio 62339 329448 0 0 3 0x14280 nfsidl nfsio 76457 451394 0 0 3 0x14280 nfsidl nfsio 55261 108274 0 0 3 0x14280 nfsidl nfsio 60361 301599 0 0 3 0x14280 nfsidl nfsio 81751 356075 0 0 3 0x14280 nfsidl nfsio 11142 270717 0 0 3 0x14280 nfsidl nfsio 16079 146439 0 0 3 0x14280 nfsidl nfsio 4646 133803 0 0 3 0x14200 acct acct 33414 319667 33524 0 2 0x482 syz-executor.1 94095 326306 33524 0 2 0x2 syz-executor.0 33524 405192 44621 0 3 0x82 thrsleep syz-fuzzer 33524 29077 44621 0 2 0x4000482 syz-fuzzer 33524 440858 44621 0 3 0x4000082 thrsleep syz-fuzzer 33524 178983 44621 0 3 0x4000082 thrsleep syz-fuzzer 33524 510578 44621 0 3 0x4000082 thrsleep syz-fuzzer 33524 323740 44621 0 2 0x4000002 syz-fuzzer 33524 152966 44621 0 3 0x4000082 thrsleep syz-fuzzer 44621 76779 82888 0 3 0x10008a pause ksh *82888 140383 35311 0 7 0x12 sshd 78617 309709 1 0 3 0x100083 ttyin getty 35311 147606 1 0 3 0x80 select sshd 19265 366727 27797 73 3 0x100090 kqread syslogd 27797 321327 1 0 3 0x100082 netio syslogd 92767 430412 1 77 3 0x100090 poll dhclient 33202 450497 1 0 3 0x80 poll dhclient 81439 53597 0 0 3 0x14200 bored smr 2650 254810 0 0 3 0x14200 pgzero zerothread 18859 459954 0 0 3 0x14200 aiodoned aiodoned 86514 464856 0 0 3 0x14200 syncer update 85599 45707 0 0 3 0x14200 cleaner cleaner 2228 476291 0 0 3 0x14200 reaper reaper 78205 158150 0 0 3 0x14200 pgdaemon pagedaemon 69662 96468 0 0 3 0x14200 bored crynlk 42357 309588 0 0 3 0x14200 bored crypto 85188 262231 0 0 3 0x40014200 acpi0 acpi0 32099 268257 0 0 3 0x14200 bored softnet 74299 277326 0 0 3 0x14200 bored systqmp 33797 509052 0 0 3 0x14200 bored systq 5474 6222 0 0 3 0x40014200 bored softclock 4021 52104 0 0 3 0x40014200 idle0 1 89294 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 6328K 6713K 78643K 10691 0 pcb 13 8K 8K 78643K 27 0 rtable 88 3K 4K 78643K 210 0 ifaddr 50 11K 11K 78643K 59 0 counters 21 16K 16K 78643K 21 0 ioctlops 0 0K 4K 78643K 33 0 iov 0 0K 12K 78643K 14 0 mount 1 1K 1K 78643K 1 0 vnodes 1216 76K 77K 78643K 1254 0 UFS quota 1 32K 32K 78643K 1 0 UFS mount 5 36K 36K 78643K 5 0 shm 2 1K 1K 78643K 2 0 VM map 2 0K 0K 78643K 2 0 sem 10 1K 1K 78643K 22 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1809 195K 288K 78643K 12938 0 file desc 4 9K 25K 78643K 109 0 sigio 0 0K 0K 78643K 6 0 proc 48 38K 54K 78643K 362 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 37 2K 2K 78643K 43 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 31 148K 148K 78643K 31 0 exec 0 0K 1K 78643K 189 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 121 23K 23K 78643K 1090 0 UVM aobj 3 2K 2K 78643K 3 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 ip6_options 0 0K 0K 78643K 8 0 NDP 7 0K 0K 78643K 11 0 temp 74 3850K 3914K 78643K 1979 0 kqueue 3 4K 8K 78643K 6 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 12 2 0 2 2 0 8 0 unpcb 120 47 0 39 1 0 1 1 0 8 0 syncache 264 6 0 6 2 1 1 1 0 8 1 tcpqe 32 96 0 96 1 1 0 1 0 8 0 tcpcb 544 28 0 24 1 0 1 1 0 8 0 inpcb 296 212 0 205 2 0 2 2 0 8 1 nd6 48 6 0 0 1 0 1 1 0 8 0 pfrktable 1344 6 0 4 1 0 1 1 0 8 0 pfrule 1360 6 0 2 1 0 1 1 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 189 0 41 12 0 12 12 0 8 1 art_table 32 190 0 41 2 0 2 2 0 8 0 art_node 16 44 0 15 1 0 1 1 0 8 0 sysvmsgpl 40 4 0 2 1 0 1 1 0 8 0 semupl 112 2 0 2 1 0 1 1 0 8 1 semapl 112 8 0 0 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 1513 0 114 88 0 88 88 0 8 0 ffsino 240 1513 0 114 83 0 83 83 0 8 0 nchpl 144 1841 0 247 60 0 60 60 0 8 0 uvmvnodes 72 1585 0 0 29 0 29 29 0 8 0 vnodes 208 1585 0 0 84 0 84 84 0 8 0 namei 1024 4635 0 4635 1 0 1 1 0 8 1 pfiaddrpl 120 4 0 0 1 0 1 1 0 8 0 scxspl 192 5350 0 5350 1 0 1 1 0 8 1 plimitpl 152 24 0 17 1 0 1 1 0 8 0 sigapl 424 316 0 268 6 0 6 6 0 8 0 futexpl 56 1644 0 1644 1 0 1 1 0 8 1 knotepl 112 66 0 47 1 0 1 1 0 8 0 kqueuepl 144 20 0 18 1 0 1 1 0 8 0 pipepl 272 84 0 74 1 0 1 1 0 8 0 fdescpl 432 281 0 268 2 0 2 2 0 8 0 filepl 120 1500 0 1405 4 0 4 4 0 8 1 lockfpl 104 25 0 24 1 0 1 1 0 8 0 lockfspl 48 9 0 8 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 95 0 88 1 0 1 1 0 8 0 zombiepl 144 268 0 267 1 0 1 1 0 8 0 processpl 928 316 0 267 7 0 7 7 0 8 0 procpl 624 410 0 355 5 0 5 5 0 8 0 sockpl 400 280 0 263 4 0 4 4 0 8 2 mcl64k 65536 2 0 2 1 0 1 1 0 8 1 mcl12k 12288 1 0 1 1 0 1 1 0 8 1 mcl8k 8192 2 0 2 1 0 1 1 0 8 1 mcl4k 4096 14 0 14 2 1 1 1 0 8 1 mcl2k 2048 91584 0 91533 18 5 13 16 0 8 6 mtagpl 96 12 0 2 2 1 1 1 0 8 0 mbufpl 256 144928 0 144819 11 1 10 10 0 8 0 bufpl 280 3366 0 128 232 0 232 232 0 8 0 anonpl 16 43189 0 27168 71 2 69 69 0 107 0 amapchunkpl 152 1266 0 1130 7 0 7 7 0 158 0 amappl16 192 1355 0 430 47 0 47 47 0 8 0 amappl15 184 41 0 39 1 0 1 1 0 8 0 amappl14 176 25 0 19 1 0 1 1 0 8 0 amappl13 168 26 0 23 1 0 1 1 0 8 0 amappl12 160 12 0 9 2 1 1 1 0 8 0 amappl11 152 48 0 38 1 0 1 1 0 8 0 amappl10 144 54 0 46 1 0 1 1 0 8 0 amappl9 136 344 0 343 1 0 1 1 0 8 0 amappl8 128 327 0 286 2 0 2 2 0 8 0 amappl7 120 153 0 139 1 0 1 1 0 8 0 amappl6 112 26 0 20 1 0 1 1 0 8 0 amappl5 104 276 0 266 1 0 1 1 0 8 0 amappl4 96 422 0 393 1 0 1 1 0 8 0 amappl3 88 100 0 94 1 0 1 1 0 8 0 amappl2 80 1425 0 1367 2 0 2 2 0 8 0 amappl1 72 15308 0 14911 23 12 11 17 0 8 2 amappl 80 615 0 576 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 2 0 0 1 0 1 1 0 8 0 uaddrrnd 24 281 0 268 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 281 0 268 1 0 1 1 0 8 0 vmmpekpl 168 6082 0 6050 2 0 2 2 0 8 0 vmmpepl 168 41894 0 39971 127 6 121 121 0 357 32 vmsppl 272 280 0 268 2 0 2 2 0 8 1 pdppl 4096 568 0 536 6 0 6 6 0 8 1 pvpl 32 143686 0 124674 163 0 163 163 0 265 1 pmappl 200 280 0 268 1 0 1 1 0 8 0 extentpl 40 53 0 36 1 0 1 1 0 8 0 phpool 112 243 0 9 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(ffffffff823cd2af) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd805c546c00,214,f4,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac3320) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da607d8,9,fffffd805c546b00,0,0,ffff80001d71d390) at tcp_usrreq+0xa54 sosend(fffffd805da607d8,0,ffff80001d6cd918,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:555 dofilewritev(ffff80001d71d390,4,ffff80001d6cd918,0,ffff80001d6cda00) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d71d390,ffff80001d6cd9b0,ffff80001d6cda00) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d6cda80) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffe45b0, 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(ffffffff823cd2af) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd805c546c00,214,f4,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac3320) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da607d8,9,fffffd805c546b00,0,0,ffff80001d71d390) at tcp_usrreq+0xa54 sosend(fffffd805da607d8,0,ffff80001d6cd918,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:555 dofilewritev(ffff80001d71d390,4,ffff80001d6cd918,0,ffff80001d6cda00) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d71d390,ffff80001d6cd9b0,ffff80001d6cda00) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d6cda80) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffe45b0, count: -10