panic: m_copym0: short mbuf chain Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *344666 32672 0 0x12 0 0 sshd db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff821cf88b) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8053918f00,37c,33c,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff8000009f5540) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805dad0008,9,fffffd8053918e00,0,0,ffff80001d797c40) at tcp_usrreq+0xa54 sosend(fffffd805dad0008,0,ffff80001d79e938,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d797c40,4,ffff80001d79e938,0,ffff80001d79ea20) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d797c40,ffff80001d79e9d0,ffff80001d79ea20) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d79eaa0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffbb890, 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(ffffffff821cf88b) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8053918f00,37c,33c,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff8000009f5540) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805dad0008,9,fffffd8053918e00,0,0,ffff80001d797c40) at tcp_usrreq+0xa54 sosend(fffffd805dad0008,0,ffff80001d79e938,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d797c40,4,ffff80001d79e938,0,ffff80001d79ea20) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d797c40,ffff80001d79e9d0,ffff80001d79ea20) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d79eaa0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffbb890, count: -10 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff80001d79e400 rbx 0xffff80001d79e4b0 rdx 0x2 rcx 0 rax 0x1 r8 0xffffffff813a55ef kprintf+0x15f r9 0x1 r10 0x2 r11 0xdcee5a821dff5287 r12 0x3000000008 r13 0xffff80001d79e410 r14 0x100 r15 0x1 rip 0xffffffff812bfa38 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff80001d79e3f0 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (sshd) pid=344666 stat=onproc flags process=12 proc=0 pri=50, usrpri=50, nice=20 forw=0xffffffffffffffff, list=0xffff80001d798600,0xffff80001d797020 process=0xffff8000ffff8ae0 user=0xffff80001d799000, 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 15474 305280 0 0 3 0x14200 bored sosplice 76163 13083 0 0 3 0x14280 nfsidl nfsio 28185 25537 0 0 3 0x14280 nfsidl nfsio 47171 109350 0 0 3 0x14280 nfsidl nfsio 60846 484425 0 0 3 0x14280 nfsidl nfsio 51133 392740 0 0 3 0x14280 nfsidl nfsio 17173 162304 0 0 3 0x14280 nfsidl nfsio 41899 111 0 0 3 0x14280 nfsidl nfsio 12068 367515 0 0 3 0x14280 nfsidl nfsio 16058 275678 0 0 3 0x14280 nfsidl nfsio 71859 244303 0 0 3 0x14280 nfsidl nfsio 13014 31665 0 0 3 0x14280 nfsidl nfsio 98536 356721 0 0 3 0x14280 nfsidl nfsio 2653 162970 0 0 3 0x14280 nfsidl nfsio 12707 306537 0 0 3 0x14280 nfsidl nfsio 77636 53545 0 0 3 0x14280 nfsidl nfsio 16288 428830 0 0 3 0x14280 nfsidl nfsio 72552 411970 0 0 3 0x14280 nfsidl nfsio 14094 152566 0 0 3 0x14280 nfsidl nfsio 9 242989 0 0 3 0x14280 nfsidl nfsio 98976 451287 0 0 3 0x14280 nfsidl nfsio 89917 135520 0 0 3 0x14200 acct acct 28113 295773 62881 0 2 0x2 syz-executor.1 40359 99946 62881 0 2 0x2 syz-executor.0 62881 149207 79496 0 3 0x82 thrsleep syz-fuzzer 62881 55728 79496 0 3 0x4000082 nanosleep syz-fuzzer 62881 229389 79496 0 3 0x4000082 thrsleep syz-fuzzer 62881 105450 79496 0 3 0x4000082 thrsleep syz-fuzzer 62881 248855 79496 0 3 0x4000082 thrsleep syz-fuzzer 62881 374689 79496 0 3 0x4000082 kqread syz-fuzzer 62881 196735 79496 0 3 0x4000082 thrsleep syz-fuzzer 79496 436368 32672 0 3 0x10008a pause ksh *32672 344666 47885 0 7 0x12 sshd 61154 126190 1 0 3 0x100083 ttyin getty 47885 71608 1 0 3 0x80 select sshd 38524 201335 60471 73 3 0x100090 kqread syslogd 60471 375121 1 0 3 0x100082 netio syslogd 45066 469883 1 77 3 0x100090 poll dhclient 18571 277291 1 0 3 0x80 poll dhclient 39999 386657 0 0 3 0x14200 bored smr 73939 277612 0 0 3 0x14200 pgzero zerothread 42865 317472 0 0 3 0x14200 aiodoned aiodoned 67829 374757 0 0 3 0x14200 syncer update 15722 342046 0 0 3 0x14200 cleaner cleaner 92133 58568 0 0 3 0x14200 reaper reaper 88417 485731 0 0 3 0x14200 pgdaemon pagedaemon 45207 425042 0 0 3 0x14200 bored crynlk 49396 77998 0 0 3 0x14200 bored crypto 61973 418824 0 0 3 0x40014200 acpi0 acpi0 54296 168334 0 0 3 0x14200 bored softnet 7436 481739 0 0 3 0x14200 bored systqmp 65543 291037 0 0 3 0x14200 bored systq 76999 158262 0 0 3 0x40014200 bored softclock 23904 357995 0 0 3 0x40014200 idle0 1 328392 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 9489 6346K 7184K 78643K 11451 0 pcb 13 8K 8K 78643K 55 0 rtable 124 7K 10K 78643K 420 0 ifaddr 66 14K 14K 78643K 142 0 counters 21 16K 16K 78643K 29 0 ioctlops 0 0K 4K 78643K 57 0 iov 0 0K 32K 78643K 38 0 mount 1 1K 1K 78643K 1 0 vnodes 1224 77K 77K 78643K 1439 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 12 0K 1K 78643K 17 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1809 195K 288K 78643K 12938 0 file desc 4 9K 25K 78643K 212 0 proc 49 38K 54K 78643K 388 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 29 0 in_multi 33 2K 2K 78643K 49 0 ether_multi 1 0K 0K 78643K 7 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 43 201K 201K 78643K 43 0 exec 0 0K 1K 78643K 197 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 123 55K 55K 78643K 1333 0 UVM aobj 2 2K 2K 78643K 2 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 ip6_options 0 0K 0K 78643K 27 0 NDP 10 0K 0K 78643K 22 0 temp 92 3038K 3102K 78643K 8225 0 kqueue 3 4K 14K 78643K 21 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 80 107 0 105 1 0 1 1 0 8 0 rtentry 112 52 0 8 2 0 2 2 0 8 0 unpcb 120 105 0 97 1 0 1 1 0 8 0 syncache 264 7 0 7 2 1 1 1 0 8 1 tcpqe 32 349 0 349 1 1 0 1 0 8 0 tcpcb 544 117 0 113 1 0 1 1 0 8 0 ipq 40 1 0 1 1 1 0 1 0 8 0 ipqe 40 45 0 45 1 1 0 1 0 8 0 inpcb 280 333 0 323 2 0 2 2 0 8 1 rttmr 72 1 0 1 1 0 1 1 0 8 1 nd6 48 6 0 0 1 0 1 1 0 8 0 pkpcb 40 2 0 2 1 1 0 1 0 8 0 pfosfp 40 1 0 0 1 0 1 1 0 8 0 pfosfpen 112 1 0 0 1 0 1 1 0 8 0 pfrktable 1344 73 0 64 2 0 2 2 0 8 1 pftag 88 18 0 16 1 0 1 1 0 8 0 pfrule 1360 20 0 13 1 0 1 1 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 200 0 4 13 0 13 13 0 8 0 art_table 32 201 0 4 2 0 2 2 0 8 0 art_node 16 49 0 9 1 0 1 1 0 8 0 sysvmsgpl 40 2 0 0 1 0 1 1 0 8 0 semapl 112 13 0 3 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 1679 0 281 88 0 88 88 0 8 0 ffsino 240 1679 0 281 83 0 83 83 0 8 0 nchpl 144 2150 0 549 60 0 60 60 0 8 0 uvmvnodes 72 1905 0 0 35 0 35 35 0 8 0 vnodes 208 1905 0 0 101 0 101 101 0 8 0 namei 1024 5764 0 5763 2 1 1 1 0 8 0 vcpupl 1984 4 0 0 1 0 1 1 0 8 0 vmpool 528 6 0 2 1 0 1 1 0 8 0 pfiaddrpl 120 28 0 21 1 0 1 1 0 8 0 scxspl 192 5993 0 5993 1 0 1 1 0 8 1 plimitpl 152 26 0 19 1 0 1 1 0 8 0 sigapl 424 420 0 371 6 0 6 6 0 8 0 futexpl 56 4318 0 4318 1 0 1 1 0 8 1 knotepl 112 79 0 60 1 0 1 1 0 8 0 kqueuepl 144 36 0 34 1 0 1 1 0 8 0 pipelkpl 16 100 0 90 1 0 1 1 0 8 0 pipepl 120 200 0 181 1 0 1 1 0 8 0 fdescpl 432 384 0 371 2 0 2 2 0 8 0 filepl 120 2455 0 2360 4 0 4 4 0 8 1 lockfpl 104 71 0 70 1 0 1 1 0 8 0 lockfspl 48 27 0 26 1 0 1 1 0 8 0 sessionpl 112 17 0 7 1 0 1 1 0 8 0 pgrppl 48 19 0 9 1 0 1 1 0 8 0 ucredpl 96 236 0 229 1 0 1 1 0 8 0 zombiepl 144 371 0 371 2 1 1 1 0 8 1 processpl 920 420 0 371 7 0 7 7 0 8 0 procpl 624 652 0 597 5 0 5 5 0 8 0 sosppl 128 2 0 2 1 0 1 1 0 8 1 sockpl 400 547 0 530 4 0 4 4 0 8 2 mcl64k 65536 18 0 18 1 0 1 1 0 8 1 mcl16k 16384 2 0 2 1 0 1 1 0 8 1 mcl12k 12288 3 0 3 1 0 1 1 0 8 1 mcl9k 9216 4 0 4 1 0 1 1 0 8 1 mcl8k 8192 8 0 8 1 0 1 1 0 8 1 mcl4k 4096 27 0 27 2 1 1 1 0 8 1 mcl2k2 2112 1 0 1 1 1 0 1 0 8 0 mcl2k 2048 75175 0 75119 16 7 9 15 0 8 1 mtagpl 80 140 0 2 4 1 3 3 0 8 0 mbufpl 256 120851 0 120474 26 1 25 25 0 8 0 bufpl 280 3713 0 126 257 0 257 257 0 8 0 anonpl 16 51251 0 35961 80 2 78 78 0 107 16 amapchunkpl 152 1638 0 1512 8 2 6 8 0 158 0 amappl16 192 1964 0 1127 54 4 50 54 0 8 7 amappl15 184 88 0 86 1 0 1 1 0 8 0 amappl14 176 25 0 18 1 0 1 1 0 8 0 amappl13 168 26 0 23 1 0 1 1 0 8 0 amappl12 160 14 0 13 2 1 1 1 0 8 0 amappl11 152 136 0 126 1 0 1 1 0 8 0 amappl10 144 18 0 10 1 0 1 1 0 8 0 amappl9 136 358 0 357 1 0 1 1 0 8 0 amappl8 128 328 0 287 2 0 2 2 0 8 0 amappl7 120 106 0 93 1 0 1 1 0 8 0 amappl6 112 113 0 110 1 0 1 1 0 8 0 amappl5 104 351 0 341 1 0 1 1 0 8 0 amappl4 96 424 0 395 1 0 1 1 0 8 0 amappl3 88 111 0 104 1 0 1 1 0 8 0 amappl2 80 2326 0 2268 2 0 2 2 0 8 0 amappl1 72 16480 0 16085 22 13 9 17 0 8 0 amappl 80 857 0 817 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 1 0 0 1 0 1 1 0 8 0 uaddrrnd 24 390 0 373 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 390 0 373 1 0 1 1 0 8 0 vmmpekpl 168 6598 0 6563 3 1 2 2 0 8 0 vmmpepl 168 52646 0 50831 111 10 101 105 0 357 15 vmsppl 272 389 0 373 2 0 2 2 0 8 0 pdppl 4096 786 0 750 6 0 6 6 0 8 1 pvpl 32 163093 0 144811 185 0 185 185 0 265 35 pmappl 200 389 0 373 1 0 1 1 0 8 0 extentpl 40 53 0 36 1 0 1 1 0 8 0 phpool 112 258 0 12 8 0 8 8 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(ffffffff821cf88b) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8053918f00,37c,33c,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff8000009f5540) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805dad0008,9,fffffd8053918e00,0,0,ffff80001d797c40) at tcp_usrreq+0xa54 sosend(fffffd805dad0008,0,ffff80001d79e938,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d797c40,4,ffff80001d79e938,0,ffff80001d79ea20) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d797c40,ffff80001d79e9d0,ffff80001d79ea20) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d79eaa0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffbb890, 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(ffffffff821cf88b) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8053918f00,37c,33c,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff8000009f5540) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805dad0008,9,fffffd8053918e00,0,0,ffff80001d797c40) at tcp_usrreq+0xa54 sosend(fffffd805dad0008,0,ffff80001d79e938,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d797c40,4,ffff80001d79e938,0,ffff80001d79ea20) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d797c40,ffff80001d79e9d0,ffff80001d79ea20) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d79eaa0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffbb890, count: -10