panic: m_copym0: short mbuf chain Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *258066 55759 0 0x12 0 0 sshd db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff821ccef7) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd806b6e3100,2d4,124,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff8000009f4ee0) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805dad17d8,9,fffffd806b6e3000,0,0,ffff80001d797eb0) at tcp_usrreq+0xa54 sosend(fffffd805dad17d8,0,ffff80001d79e188,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d797eb0,4,ffff80001d79e188,0,ffff80001d79e270) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d797eb0,ffff80001d79e220,ffff80001d79e270) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d79e2f0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffbbc40, 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(ffffffff821ccef7) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd806b6e3100,2d4,124,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff8000009f4ee0) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805dad17d8,9,fffffd806b6e3000,0,0,ffff80001d797eb0) at tcp_usrreq+0xa54 sosend(fffffd805dad17d8,0,ffff80001d79e188,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d797eb0,4,ffff80001d79e188,0,ffff80001d79e270) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d797eb0,ffff80001d79e220,ffff80001d79e270) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d79e2f0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffbbc40, count: -10 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff80001d79dc50 rbx 0xffff80001d79dd00 rdx 0x2 rcx 0 rax 0x1 r8 0xffffffff813a05cf kprintf+0x15f r9 0x1 r10 0x2 r11 0x992163184debcb5c r12 0x3000000008 r13 0xffff80001d79dc60 r14 0x100 r15 0x1 rip 0xffffffff816eb248 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff80001d79dc40 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (sshd) pid=258066 stat=onproc flags process=12 proc=0 pri=24, usrpri=50, nice=20 forw=0xffffffffffffffff, list=0xffff80001d798600,0xffff80001d797500 process=0xffff8000ffff8018 user=0xffff80001d799000, vmspace=0xfffffd806bc09660 estcpu=0, cpticks=0, pctcpu=0.0 user=0, sys=0, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 22308 286171 5090 0 2 0 syz-executor.0 22308 52693 5090 0 2 0x4000000 syz-executor.0 22308 28592 5090 0 2 0x4000000 syz-executor.0 4712 340885 0 0 3 0x14200 acct acct 41000 114121 0 0 3 0x14200 bored sosplice 34381 341425 0 0 3 0x14280 nfsidl nfsio 41939 260424 0 0 3 0x14280 nfsidl nfsio 91028 215554 0 0 3 0x14280 nfsidl nfsio 97528 168075 0 0 3 0x14280 nfsidl nfsio 28694 430221 0 0 3 0x14280 nfsidl nfsio 95441 18706 0 0 3 0x14280 nfsidl nfsio 18424 383067 0 0 3 0x14280 nfsidl nfsio 74499 33542 0 0 3 0x14280 nfsidl nfsio 28134 130857 0 0 3 0x14280 nfsidl nfsio 50437 441233 0 0 3 0x14280 nfsidl nfsio 8696 283708 0 0 3 0x14280 nfsidl nfsio 58633 302975 0 0 3 0x14280 nfsidl nfsio 71430 230044 0 0 3 0x14280 nfsidl nfsio 72583 278755 0 0 3 0x14280 nfsidl nfsio 98004 351810 0 0 3 0x14280 nfsidl nfsio 64724 366789 0 0 3 0x14280 nfsidl nfsio 66996 211056 0 0 3 0x14280 nfsidl nfsio 22512 501788 0 0 3 0x14280 nfsidl nfsio 64409 144637 0 0 3 0x14280 nfsidl nfsio 71164 239632 0 0 3 0x14280 nfsidl nfsio 5090 511925 85164 0 3 0x82 nanosleep syz-executor.0 9682 200210 85164 0 2 0x2 syz-executor.1 85164 254371 24504 0 3 0x82 thrsleep syz-fuzzer 85164 228194 24504 0 2 0x4000002 syz-fuzzer 85164 26007 24504 0 3 0x4000082 thrsleep syz-fuzzer 85164 147178 24504 0 3 0x4000082 thrsleep syz-fuzzer 85164 512950 24504 0 2 0x4000002 syz-fuzzer 85164 293907 24504 0 3 0x4000082 thrsleep syz-fuzzer 85164 519679 24504 0 3 0x4000082 thrsleep syz-fuzzer 85164 21557 24504 0 3 0x4000082 thrsleep syz-fuzzer 24504 400714 55759 0 3 0x10008a pause ksh *55759 258066 66046 0 7 0x12 sshd 57864 291319 1 0 3 0x100083 ttyin getty 66046 458051 1 0 3 0x80 select sshd 42222 343345 9604 73 3 0x100090 kqread syslogd 9604 103213 1 0 3 0x100082 netio syslogd 79540 206671 1 77 3 0x100090 poll dhclient 98913 107781 1 0 3 0x80 poll dhclient 23666 230923 0 0 3 0x14200 bored smr 775 422882 0 0 2 0x14200 zerothread 84425 2443 0 0 3 0x14200 aiodoned aiodoned 64147 29008 0 0 3 0x14200 syncer update 77692 289678 0 0 3 0x14200 cleaner cleaner 44251 147241 0 0 3 0x14200 reaper reaper 80718 440910 0 0 3 0x14200 pgdaemon pagedaemon 15584 115792 0 0 3 0x14200 bored crynlk 39114 381357 0 0 3 0x14200 bored crypto 45226 340329 0 0 3 0x40014200 acpi0 acpi0 8695 427263 0 0 3 0x14200 bored softnet 84407 441683 0 0 3 0x14200 bored systqmp 2574 11080 0 0 3 0x14200 bored systq 52392 37247 0 0 3 0x40014200 bored softclock 91445 289674 0 0 3 0x40014200 idle0 1 370354 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 9513 6355K 7006K 78643K 11410 0 pcb 13 8K 8K 78643K 85 0 rtable 106 5K 8K 78643K 413 0 ifaddr 87 17K 17K 78643K 163 0 counters 21 16K 16K 78643K 24 0 ioctlops 0 0K 4K 78643K 87 0 iov 0 0K 16K 78643K 64 0 mount 1 1K 1K 78643K 1 0 vnodes 1219 77K 77K 78643K 1450 0 UFS quota 1 32K 32K 78643K 1 0 UFS mount 5 36K 36K 78643K 5 0 shm 2 1K 5K 78643K 8 0 VM map 2 0K 0K 78643K 2 0 sem 12 0K 1K 78643K 32 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1809 195K 288K 78643K 12938 0 file desc 5 13K 25K 78643K 380 0 sigio 0 0K 0K 78643K 6 0 proc 50 38K 54K 78643K 406 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 25 0 in_multi 69 3K 3K 78643K 117 0 ether_multi 1 0K 0K 78643K 13 0 mrt 0 0K 0K 78643K 2 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 217 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 144 121K 123K 78643K 1747 0 UVM aobj 20 4K 4K 78643K 24 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 ip6_options 0 0K 0K 78643K 80 0 NDP 13 0K 0K 78643K 21 0 temp 107 3041K 3105K 78643K 5307 0 kqueue 6 10K 24K 78643K 40 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 80 368 0 366 1 0 1 1 0 8 0 rtentry 112 54 0 14 2 0 2 2 0 8 0 unpcb 120 171 0 163 1 0 1 1 0 8 0 syncache 264 10 0 10 2 2 0 1 0 8 0 tcpqe 32 112 0 112 2 2 0 1 0 8 0 tcpcb 544 144 0 139 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 280 413 0 404 4 2 2 2 0 8 1 rttmr 72 1 0 1 1 0 1 1 0 8 1 nd6 48 8 0 5 1 0 1 1 0 8 0 pfstscr 40 1 0 0 1 0 1 1 0 8 0 pfrktable 1344 78 0 74 2 1 1 1 0 8 0 pftag 88 16 0 16 2 1 1 1 0 8 1 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 28 0 12 2 0 2 2 0 8 0 art_heap8 4096 2 0 0 2 0 2 2 0 8 0 art_heap4 256 225 0 56 13 0 13 13 0 8 0 art_table 32 227 0 56 2 0 2 2 0 8 0 art_node 16 53 0 15 1 0 1 1 0 8 0 sysvmsgpl 40 5 0 2 1 0 1 1 0 8 0 semupl 112 2 0 2 1 1 0 1 0 8 0 semapl 112 22 0 12 1 0 1 1 0 8 0 shmpl 112 22 0 4 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 1899 0 500 88 0 88 88 0 8 0 ffsino 240 1899 0 500 83 0 83 83 0 8 0 nchpl 144 2728 0 1124 60 0 60 60 0 8 0 uvmvnodes 72 2112 0 0 39 0 39 39 0 8 0 vnodes 208 2112 0 0 112 0 112 112 0 8 0 namei 1024 7207 0 7207 3 2 1 1 0 8 1 vcpupl 1984 11 0 0 2 0 2 2 0 8 0 vmpool 528 15 0 4 1 0 1 1 0 8 0 pfiaddrpl 120 26 0 22 2 1 1 1 0 8 0 scxspl 192 7543 0 7543 1 0 1 1 0 8 1 plimitpl 152 45 0 38 1 0 1 1 0 8 0 sigapl 424 589 0 539 6 0 6 6 0 8 0 futexpl 56 7585 0 7585 3 2 1 1 0 8 1 knotepl 112 110 0 91 1 0 1 1 0 8 0 kqueuepl 144 81 0 73 1 0 1 1 0 8 0 pipelkpl 16 130 0 120 1 0 1 1 0 8 0 pipepl 120 260 0 241 1 0 1 1 0 8 0 fdescpl 432 552 0 538 2 0 2 2 0 8 0 filepl 120 3631 0 3531 4 0 4 4 0 8 0 lockfpl 104 58 0 57 1 0 1 1 0 8 0 lockfspl 48 23 0 22 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 96 347 0 340 1 0 1 1 0 8 0 zombiepl 144 539 0 539 2 1 1 1 0 8 1 processpl 920 589 0 539 7 0 7 7 0 8 0 procpl 624 1024 0 965 6 1 5 6 0 8 0 sosppl 128 14 0 13 1 0 1 1 0 8 0 sockpl 400 953 0 935 4 1 3 4 0 8 1 mcl64k 65536 557 0 553 67 66 1 65 0 8 0 mcl16k 16384 1 0 1 1 1 0 1 0 8 0 mcl12k 12288 7 0 7 3 2 1 1 0 8 1 mcl9k 9216 8 0 8 4 3 1 1 0 8 1 mcl8k 8192 15 0 15 3 2 1 1 0 8 1 mcl4k 4096 41 0 41 4 3 1 1 0 8 1 mcl2k2 2112 2 0 2 1 1 0 1 0 8 0 mcl2k 2048 76234 0 76185 16 9 7 14 0 8 0 mtagpl 80 80 0 2 3 1 2 2 0 8 0 mbufpl 256 123826 0 123566 56 36 20 45 0 8 3 bufpl 280 4198 0 130 291 0 291 291 0 8 0 anonpl 16 71853 0 56313 90 26 64 79 0 107 1 amapchunkpl 152 3482 0 3320 26 12 14 20 0 158 6 amappl16 192 3073 0 2199 67 22 45 56 0 8 1 amappl15 184 1 0 0 1 0 1 1 0 8 0 amappl14 176 23 0 20 1 0 1 1 0 8 0 amappl13 168 28 0 24 1 0 1 1 0 8 0 amappl12 160 25 0 20 1 0 1 1 0 8 0 amappl11 152 393 0 381 1 0 1 1 0 8 0 amappl10 144 17 0 12 1 0 1 1 0 8 0 amappl9 136 350 0 349 1 0 1 1 0 8 0 amappl8 128 344 0 299 2 0 2 2 0 8 0 amappl7 120 107 0 94 1 0 1 1 0 8 0 amappl6 112 370 0 362 1 0 1 1 0 8 0 amappl5 104 537 0 526 1 0 1 1 0 8 0 amappl4 96 429 0 397 1 0 1 1 0 8 0 amappl3 88 113 0 108 1 0 1 1 0 8 0 amappl2 80 3608 0 3540 2 0 2 2 0 8 0 amappl1 72 19091 0 18673 23 14 9 17 0 8 0 amappl 80 1250 0 1198 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 23 0 4 1 0 1 1 0 8 0 uaddrrnd 24 567 0 542 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 567 0 542 1 0 1 1 0 8 0 vmmpekpl 168 7169 0 7134 2 0 2 2 0 8 0 vmmpepl 168 71754 0 69739 151 58 93 145 0 357 1 vmsppl 272 566 0 542 2 0 2 2 0 8 0 pdppl 4096 1140 0 1095 7 1 6 7 0 8 0 pvpl 32 209955 0 191561 200 45 155 187 0 265 5 pmappl 200 566 0 542 2 0 2 2 0 8 0 extentpl 40 53 0 36 1 0 1 1 0 8 0 phpool 112 363 0 124 10 3 7 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(ffffffff821ccef7) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd806b6e3100,2d4,124,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff8000009f4ee0) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805dad17d8,9,fffffd806b6e3000,0,0,ffff80001d797eb0) at tcp_usrreq+0xa54 sosend(fffffd805dad17d8,0,ffff80001d79e188,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d797eb0,4,ffff80001d79e188,0,ffff80001d79e270) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d797eb0,ffff80001d79e220,ffff80001d79e270) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d79e2f0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffbbc40, 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(ffffffff821ccef7) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd806b6e3100,2d4,124,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff8000009f4ee0) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805dad17d8,9,fffffd806b6e3000,0,0,ffff80001d797eb0) at tcp_usrreq+0xa54 sosend(fffffd805dad17d8,0,ffff80001d79e188,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d797eb0,4,ffff80001d79e188,0,ffff80001d79e270) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d797eb0,ffff80001d79e220,ffff80001d79e270) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d79e2f0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffbbc40, count: -10