panic: m_copym0: short mbuf chain Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *102977 11587 0 0x12 0 0 sshd db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff823d6a71) at panic+0x164 sys/kern/subr_prf.c:218 m_copym(fffffd8053105f00,cc,304,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac3540) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da74198,9,fffffd8053105e00,0,0,ffff80001d71cc40) at tcp_usrreq+0xa54 sosend(fffffd805da74198,0,ffff80001d6cd578,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:555 dofilewritev(ffff80001d71cc40,4,ffff80001d6cd578,0,ffff80001d6cd660) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d71cc40,ffff80001d6cd610,ffff80001d6cd660) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d6cd6e0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffc1230, 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(ffffffff823d6a71) at panic+0x164 sys/kern/subr_prf.c:218 m_copym(fffffd8053105f00,cc,304,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac3540) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da74198,9,fffffd8053105e00,0,0,ffff80001d71cc40) at tcp_usrreq+0xa54 sosend(fffffd805da74198,0,ffff80001d6cd578,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:555 dofilewritev(ffff80001d71cc40,4,ffff80001d6cd578,0,ffff80001d6cd660) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d71cc40,ffff80001d6cd610,ffff80001d6cd660) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d6cd6e0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffc1230, count: -10 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff80001d6cd040 rbx 0xffff80001d6cd0f0 rdx 0x2 rcx 0 rax 0x1 r8 0xffffffff819e2c3f kprintf+0x15f r9 0x1 r10 0x2 r11 0x86024e4f4315c80c r12 0x3000000008 r13 0xffff80001d6cd050 r14 0x100 r15 0x1 rip 0xffffffff823b1bf8 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff80001d6cd030 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (sshd) pid=102977 stat=onproc flags process=12 proc=0 pri=24, usrpri=50, nice=20 forw=0xffffffffffffffff, list=0xffff80001d71c010,0xffff80001d71c770 process=0xffff80001d707238 user=0xffff80001d6c8000, vmspace=0xfffffd806bc0abb0 estcpu=0, cpticks=0, pctcpu=0.0 user=0, sys=0, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 27086 359482 25180 0 2 0 syz-executor.1 27086 381258 25180 0 2 0x4000000 syz-executor.1 25180 326789 64536 0 3 0x82 nanosleep syz-executor.1 31004 153748 1 0 3 0x100083 ttyin getty 65392 174725 0 0 3 0x14200 bored sosplice 1278 32804 0 0 3 0x14280 nfsidl nfsio 37905 82317 0 0 3 0x14280 nfsidl nfsio 10628 202059 0 0 3 0x14280 nfsidl nfsio 66044 194869 0 0 3 0x14280 nfsidl nfsio 43024 55100 0 0 3 0x14280 nfsidl nfsio 80669 371645 0 0 3 0x14280 nfsidl nfsio 17289 267755 0 0 3 0x14280 nfsidl nfsio 10001 418040 0 0 3 0x14280 nfsidl nfsio 72823 282420 0 0 3 0x14280 nfsidl nfsio 32192 172107 0 0 3 0x14280 nfsidl nfsio 95650 404883 0 0 3 0x14280 nfsidl nfsio 38373 345732 0 0 3 0x14280 nfsidl nfsio 34519 256632 0 0 3 0x14280 nfsidl nfsio 48485 108809 0 0 3 0x14280 nfsidl nfsio 49282 498788 0 0 3 0x14280 nfsidl nfsio 92276 32925 0 0 3 0x14280 nfsidl nfsio 69708 516155 0 0 3 0x14280 nfsidl nfsio 92922 261108 0 0 3 0x14280 nfsidl nfsio 59850 234827 0 0 3 0x14280 nfsidl nfsio 98848 104451 0 0 3 0x14280 nfsidl nfsio 88926 438250 64536 0 2 0x2 syz-executor.0 64536 77864 43320 0 3 0x82 thrsleep syz-fuzzer 64536 21972 43320 0 3 0x4000082 nanosleep syz-fuzzer 64536 172606 43320 0 3 0x4000082 thrsleep syz-fuzzer 64536 297141 43320 0 3 0x4000082 thrsleep syz-fuzzer 64536 495333 43320 0 3 0x4000082 thrsleep syz-fuzzer 64536 507913 43320 0 2 0x4000002 syz-fuzzer 43320 470576 11587 0 3 0x10008a pause ksh *11587 102977 80871 0 7 0x12 sshd 80871 173424 1 0 3 0x80 select sshd 78332 293207 74377 73 3 0x100090 kqread syslogd 74377 473198 1 0 3 0x100082 netio syslogd 90622 161674 1 77 3 0x100090 poll dhclient 38143 359657 1 0 3 0x80 poll dhclient 62430 75962 0 0 3 0x14200 bored smr 68232 35943 0 0 2 0x14200 zerothread 5772 200018 0 0 3 0x14200 aiodoned aiodoned 92127 318434 0 0 3 0x14200 syncer update 7159 149787 0 0 3 0x14200 cleaner cleaner 85222 509408 0 0 3 0x14200 reaper reaper 84952 395227 0 0 3 0x14200 pgdaemon pagedaemon 83183 331486 0 0 3 0x14200 bored crynlk 85404 204692 0 0 3 0x14200 bored crypto 28762 484167 0 0 3 0x40014200 acpi0 acpi0 83263 165796 0 0 3 0x14200 bored softnet 61165 447373 0 0 3 0x14200 bored systqmp 39186 31165 0 0 3 0x14200 bored systq 72606 46406 0 0 3 0x40014200 bored softclock 66767 134699 0 0 3 0x40014200 idle0 1 96154 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 9502 6359K 6730K 78643K 11422 0 pcb 13 8K 8K 78643K 96 0 rtable 101 4K 8K 78643K 595 0 ifaddr 78 15K 16K 78643K 216 0 sysctl 2 0K 0K 78643K 2 0 counters 21 16K 16K 78643K 34 0 ioctlops 0 0K 4K 78643K 118 0 iov 0 0K 32K 78643K 104 0 mount 1 1K 1K 78643K 1 0 vnodes 1222 77K 77K 78643K 1527 0 UFS quota 1 32K 32K 78643K 1 0 UFS mount 5 36K 36K 78643K 5 0 shm 2 1K 5K 78643K 11 0 VM map 2 0K 0K 78643K 2 0 sem 12 0K 0K 78643K 166 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1809 195K 288K 78643K 12938 0 file desc 5 13K 25K 78643K 783 0 sigio 0 0K 0K 78643K 2 0 proc 50 38K 63K 78643K 472 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 51 0 in_multi 60 3K 3K 78643K 176 0 ether_multi 1 0K 0K 78643K 17 0 mrt 0 0K 0K 78643K 4 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 255 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 55K 80K 78643K 2644 0 UVM aobj 25 2K 2K 78643K 26 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 ip6_options 0 0K 0K 78643K 116 0 NDP 13 0K 0K 78643K 43 0 temp 114 3859K 3936K 78643K 9483 0 kqueue 3 4K 10K 78643K 31 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 13 0 5 1 0 1 1 0 8 0 rtpcb 80 40 0 38 1 0 1 1 0 8 0 rtentry 112 107 0 71 2 0 2 2 0 8 0 unpcb 120 381 0 373 1 0 1 1 0 8 0 syncache 264 8 0 8 3 3 0 1 0 8 0 tcpqe 32 9 0 9 3 3 0 1 0 8 0 tcpcb 544 561 0 542 8 5 3 4 0 8 1 ipq 40 39 0 39 2 1 1 1 0 8 1 ipqe 40 116 0 116 2 1 1 1 0 8 1 inpcb 296 1478 0 1464 3 1 2 2 0 8 0 rttmr 72 1 0 1 1 1 0 1 0 8 0 ip6q 72 2 0 1 1 0 1 1 0 8 0 ip6af 40 2 0 2 1 1 0 1 0 8 0 nd6 48 30 0 26 1 0 1 1 0 8 0 pkpcb 40 6 0 6 2 2 0 1 0 8 0 ppxss 1136 1 0 1 1 1 0 1 0 8 0 pfrktable 1344 67 0 65 3 2 1 1 0 8 0 pftag 88 10 0 10 3 2 1 1 0 8 1 pfrule 1360 27 0 13 3 1 2 2 0 8 0 art_heap8 4096 2 0 0 2 0 2 2 0 8 0 art_heap4 256 450 0 301 15 1 14 15 0 8 2 art_table 32 452 0 301 2 0 2 2 0 8 0 art_node 16 106 0 76 1 0 1 1 0 8 0 sysvmsgpl 40 19 0 13 1 0 1 1 0 8 0 semapl 112 164 0 154 1 0 1 1 0 8 0 shmpl 112 23 0 2 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 2429 0 1031 88 0 88 88 0 8 0 ffsino 240 2429 0 1031 83 0 83 83 0 8 0 nchpl 144 3696 0 2110 60 0 60 60 0 8 0 uvmvnodes 72 2673 0 0 49 0 49 49 0 8 0 vnodes 208 2673 0 0 141 0 141 141 0 8 0 namei 1024 10875 0 10875 3 2 1 1 0 8 1 vcpupl 1984 2 0 0 1 0 1 1 0 8 0 vmpool 528 9 0 7 1 0 1 1 0 8 0 pfiaddrpl 120 20 0 18 3 2 1 1 0 8 0 scxspl 192 10947 0 10947 2 1 1 1 0 8 1 plimitpl 152 76 0 69 1 0 1 1 0 8 0 sigapl 424 988 0 939 6 0 6 6 0 8 0 futexpl 56 16116 0 16116 3 2 1 1 0 8 1 knotepl 112 107 0 87 1 0 1 1 0 8 0 kqueuepl 144 78 0 76 1 0 1 1 0 8 0 pipepl 272 183 0 172 3 1 2 2 0 8 1 fdescpl 432 953 0 939 2 0 2 2 0 8 0 filepl 120 5953 0 5856 4 0 4 4 0 8 0 lockfpl 104 128 0 126 1 0 1 1 0 8 0 lockfspl 48 52 0 50 1 0 1 1 0 8 0 sessionpl 112 19 0 9 1 0 1 1 0 8 0 pgrppl 48 27 0 17 1 0 1 1 0 8 0 ucredpl 96 1015 0 1008 1 0 1 1 0 8 0 zombiepl 144 939 0 939 1 0 1 1 0 8 1 processpl 928 988 0 939 8 1 7 7 0 8 0 procpl 624 1865 0 1810 5 0 5 5 0 8 0 sosppl 128 7 0 7 2 1 1 1 0 8 1 sockpl 400 1911 0 1889 5 1 4 4 0 8 1 mcl64k 65536 44 0 44 4 3 1 1 0 8 1 mcl16k 16384 4 0 4 2 2 0 1 0 8 0 mcl12k 12288 35 0 35 5 4 1 1 0 8 1 mcl9k 9216 16 0 16 4 3 1 1 0 8 1 mcl8k 8192 33 0 33 4 3 1 1 0 8 1 mcl4k 4096 46 0 46 5 4 1 1 0 8 1 mcl2k2 2112 7 0 7 4 3 1 1 0 8 1 mcl2k 2048 96156 0 96112 21 14 7 16 0 8 1 mtagpl 96 70 0 29 3 1 2 2 0 8 0 mbufpl 256 159599 0 159299 126 99 27 119 0 8 8 bufpl 280 4487 0 120 312 0 312 312 0 8 0 anonpl 16 103814 0 85759 97 19 78 89 0 107 2 amapchunkpl 152 5342 0 5165 31 10 21 21 0 158 13 amappl16 192 4051 0 3045 68 14 54 60 0 8 3 amappl15 184 642 0 640 1 0 1 1 0 8 0 amappl14 176 2 0 0 1 0 1 1 0 8 0 amappl13 168 33 0 30 1 0 1 1 0 8 0 amappl12 160 24 0 22 1 0 1 1 0 8 0 amappl11 152 47 0 37 1 0 1 1 0 8 0 amappl10 144 654 0 649 1 0 1 1 0 8 0 amappl9 136 454 0 450 1 0 1 1 0 8 0 amappl8 128 326 0 293 2 0 2 2 0 8 0 amappl7 120 477 0 464 1 0 1 1 0 8 0 amappl6 112 27 0 21 1 0 1 1 0 8 0 amappl5 104 879 0 867 1 0 1 1 0 8 0 amappl4 96 447 0 421 1 0 1 1 0 8 0 amappl3 88 164 0 156 1 0 1 1 0 8 0 amappl2 80 7042 0 6973 2 0 2 2 0 8 0 amappl1 72 30084 0 29678 24 15 9 17 0 8 0 amappl 80 2122 0 2068 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 25 0 1 1 0 1 1 0 8 0 uaddrrnd 24 962 0 946 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 962 0 946 1 0 1 1 0 8 0 vmmpekpl 168 9167 0 9135 2 0 2 2 0 8 0 vmmpepl 168 121508 0 119411 160 29 131 132 0 357 36 vmsppl 272 961 0 946 3 1 2 2 0 8 0 pdppl 4096 1930 0 1894 8 3 5 6 0 8 0 pvpl 32 304847 0 283692 227 40 187 207 0 265 9 pmappl 200 961 0 946 1 0 1 1 0 8 0 extentpl 40 53 0 36 1 0 1 1 0 8 0 phpool 112 393 0 142 10 0 10 10 0 8 2 ddb> machine ddbcpu 0 No such command ddb> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff823d6a71) at panic+0x164 sys/kern/subr_prf.c:218 m_copym(fffffd8053105f00,cc,304,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac3540) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da74198,9,fffffd8053105e00,0,0,ffff80001d71cc40) at tcp_usrreq+0xa54 sosend(fffffd805da74198,0,ffff80001d6cd578,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:555 dofilewritev(ffff80001d71cc40,4,ffff80001d6cd578,0,ffff80001d6cd660) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d71cc40,ffff80001d6cd610,ffff80001d6cd660) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d6cd6e0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffc1230, 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(ffffffff823d6a71) at panic+0x164 sys/kern/subr_prf.c:218 m_copym(fffffd8053105f00,cc,304,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac3540) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da74198,9,fffffd8053105e00,0,0,ffff80001d71cc40) at tcp_usrreq+0xa54 sosend(fffffd805da74198,0,ffff80001d6cd578,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:555 dofilewritev(ffff80001d71cc40,4,ffff80001d6cd578,0,ffff80001d6cd660) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d71cc40,ffff80001d6cd610,ffff80001d6cd660) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d6cd6e0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffc1230, count: -10