panic: m_copym0: short mbuf chain Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *171732 29571 0 0x12 0 0 sshd db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff823caafe) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd805e241200,4f4,334,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac2760) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da76648,9,fffffd805e241100,0,0,ffff80001d717280) at tcp_usrreq+0xa54 sosend(fffffd805da76648,0,ffff80001d71de98,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:555 dofilewritev(ffff80001d717280,4,ffff80001d71de98,0,ffff80001d71df80) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d717280,ffff80001d71df30,ffff80001d71df80) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d71e000) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffd48f0, 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(ffffffff823caafe) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd805e241200,4f4,334,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac2760) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da76648,9,fffffd805e241100,0,0,ffff80001d717280) at tcp_usrreq+0xa54 sosend(fffffd805da76648,0,ffff80001d71de98,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:555 dofilewritev(ffff80001d717280,4,ffff80001d71de98,0,ffff80001d71df80) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d717280,ffff80001d71df30,ffff80001d71df80) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d71e000) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffd48f0, count: -10 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff80001d71d960 rbx 0xffff80001d71da10 rdx 0x2 rcx 0 rax 0x1 r8 0xffffffff819dd21f kprintf+0x15f r9 0x1 r10 0x2 r11 0x8e3ef4ed9a31d3d4 r12 0x3000000008 r13 0xffff80001d71d970 r14 0x100 r15 0x1 rip 0xffffffff820d2da8 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff80001d71d950 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (sshd) pid=171732 stat=onproc flags process=12 proc=0 pri=24, usrpri=50, nice=20 forw=0xffffffffffffffff, list=0xffff80001d718870,0xffff80001d717770 process=0xffff8000ffff8e78 user=0xffff80001d719000, vmspace=0xfffffd806bc09990 estcpu=0, cpticks=0, pctcpu=0.0 user=0, sys=0, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 487 224528 46431 0 2 0 syz-executor.0 487 285192 46431 0 2 0x4000000 syz-executor.0 43142 146639 0 0 3 0x14200 acct acct 99076 298113 0 0 3 0x14200 bored sosplice 46431 39006 38097 0 2 0x482 syz-executor.0 73234 300678 38097 0 2 0x2 syz-executor.1 38097 227008 97343 0 3 0x82 thrsleep syz-fuzzer 38097 140743 97343 0 2 0x4000482 syz-fuzzer 38097 266191 97343 0 3 0x4000082 thrsleep syz-fuzzer 38097 157868 97343 0 3 0x4000082 thrsleep syz-fuzzer 38097 418960 97343 0 3 0x4000082 thrsleep syz-fuzzer 38097 80493 97343 0 2 0x4000002 syz-fuzzer 38097 93095 97343 0 3 0x4000082 thrsleep syz-fuzzer 97343 345541 29571 0 3 0x10008a pause ksh *29571 171732 89685 0 7 0x12 sshd 67419 120927 1 0 3 0x100083 ttyin getty 89685 442411 1 0 3 0x80 select sshd 71425 10691 27866 73 3 0x100090 kqread syslogd 27866 319568 1 0 3 0x100082 netio syslogd 78430 399228 1 77 3 0x100090 poll dhclient 11302 40751 1 0 3 0x80 poll dhclient 6112 223532 0 0 3 0x14200 bored smr 64788 428176 0 0 2 0x14200 zerothread 47165 116661 0 0 3 0x14200 aiodoned aiodoned 31689 630 0 0 3 0x14200 syncer update 38631 436843 0 0 3 0x14200 cleaner cleaner 45596 64329 0 0 3 0x14200 reaper reaper 57210 295747 0 0 3 0x14200 pgdaemon pagedaemon 13887 444217 0 0 3 0x14200 bored crynlk 39042 377189 0 0 3 0x14200 bored crypto 7250 207557 0 0 3 0x40014200 acpi0 acpi0 11390 219798 0 0 3 0x14200 bored softnet 49035 419336 0 0 3 0x14200 bored systqmp 45818 359159 0 0 3 0x14200 bored systq 3263 360285 0 0 3 0x40014200 bored softclock 99717 134511 0 0 3 0x40014200 idle0 1 77685 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 9520 6349K 7054K 78643K 11046 0 pcb 13 8K 8K 78643K 55 0 rtable 106 6K 6K 78643K 331 0 ifaddr 84 15K 15K 78643K 125 0 counters 21 16K 16K 78643K 24 0 ioctlops 0 0K 4K 78643K 57 0 iov 0 0K 12K 78643K 49 0 mount 1 1K 1K 78643K 1 0 vnodes 1216 76K 77K 78643K 1347 0 UFS quota 1 32K 32K 78643K 1 0 UFS mount 5 36K 36K 78643K 5 0 shm 2 1K 5K 78643K 7 0 VM map 2 0K 0K 78643K 2 0 sem 12 0K 0K 78643K 48 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1809 195K 288K 78643K 12938 0 file desc 5 13K 25K 78643K 253 0 sigio 0 0K 0K 78643K 2 0 proc 49 38K 62K 78643K 411 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 45 0 in_multi 41 2K 2K 78643K 102 0 ether_multi 1 0K 0K 78643K 6 0 mrt 0 0K 0K 78643K 1 0 ISOFS mount 1 32K 32K 78643K 1 0 MSDOSFS mount 1 16K 16K 78643K 1 0 ttys 37 175K 175K 78643K 37 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 121 23K 25K 78643K 1425 0 UVM aobj 12 4K 4K 78643K 14 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 ip6_options 0 0K 0K 78643K 47 0 NDP 15 0K 0K 78643K 28 0 temp 117 3857K 3921K 78643K 9765 0 kqueue 3 4K 8K 78643K 17 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 2 1 0 1 1 0 8 0 rtpcb 80 31 0 29 1 0 1 1 0 8 0 rtentry 112 65 0 28 2 0 2 2 0 8 0 unpcb 120 187 0 179 1 0 1 1 0 8 0 syncache 264 4 0 4 1 1 0 1 0 8 0 tcpqe 32 405 0 405 1 1 0 1 0 8 0 tcpcb 544 164 0 160 1 0 1 1 0 8 0 inpcb 296 383 0 376 2 0 2 2 0 8 1 nd6 48 16 0 12 1 0 1 1 0 8 0 pfrke_plain 160 23 0 20 1 0 1 1 0 8 0 pfrktable 1344 21 0 16 1 0 1 1 0 8 0 pfrule 1360 10 0 2 1 0 1 1 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 406 0 219 17 0 17 17 0 8 4 art_table 32 407 0 219 3 0 3 3 0 8 0 art_node 16 64 0 30 1 0 1 1 0 8 0 sysvmsgpl 40 14 0 6 1 0 1 1 0 8 0 semapl 112 44 0 34 1 0 1 1 0 8 0 shmpl 112 12 0 2 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 1746 0 350 88 0 88 88 0 8 0 ffsino 240 1746 0 350 83 0 83 83 0 8 0 nchpl 144 2312 0 708 60 0 60 60 0 8 0 rtmask 32 4 0 2 1 0 1 1 0 8 0 uvmvnodes 72 1877 0 0 35 0 35 35 0 8 0 vnodes 208 1877 0 0 99 0 99 99 0 8 0 namei 1024 6216 0 6216 2 1 1 1 0 8 1 vmpool 528 6 0 6 2 1 1 1 0 8 1 pfiaddrpl 120 6 0 2 1 0 1 1 0 8 0 scsiplug 64 2 0 2 1 0 1 1 0 8 1 scxspl 192 7355 0 7355 1 0 1 1 0 8 1 plimitpl 152 33 0 26 1 0 1 1 0 8 0 sigapl 424 441 0 411 4 0 4 4 0 8 0 futexpl 56 4947 0 4947 1 0 1 1 0 8 1 knotepl 112 96 0 77 1 0 1 1 0 8 0 kqueuepl 144 36 0 34 1 0 1 1 0 8 0 pipepl 272 112 0 102 1 0 1 1 0 8 0 fdescpl 432 425 0 411 2 0 2 2 0 8 0 filepl 120 2612 0 2517 4 0 4 4 0 8 1 lockfpl 104 53 0 52 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 19 0 9 1 0 1 1 0 8 0 ucredpl 96 309 0 302 1 0 1 1 0 8 0 zombiepl 144 411 0 411 2 1 1 1 0 8 1 processpl 920 441 0 411 4 0 4 4 0 8 0 procpl 624 716 0 679 4 0 4 4 0 8 0 sockpl 400 602 0 585 4 1 3 4 0 8 1 mcl64k 65536 40 0 40 1 0 1 1 0 8 1 mcl16k 16384 2 0 2 1 0 1 1 0 8 1 mcl12k 12288 7 0 7 1 0 1 1 0 8 1 mcl9k 9216 5 0 5 1 0 1 1 0 8 1 mcl8k 8192 2 0 2 1 1 0 1 0 8 0 mcl4k 4096 33 0 33 2 1 1 1 0 8 1 mcl2k2 2112 2 0 2 1 1 0 1 0 8 0 mcl2k 2048 77912 0 77848 20 11 9 18 0 8 0 mtagpl 96 21 0 2 2 1 1 1 0 8 0 mbufpl 256 124781 0 124562 17 2 15 15 0 8 0 bufpl 280 4148 0 125 288 0 288 288 0 8 0 anonpl 16 55125 0 38817 72 2 70 70 0 107 2 amapchunkpl 152 1993 0 1865 14 1 13 13 0 158 6 amappl16 192 2305 0 1412 47 0 47 47 0 8 2 amappl15 184 3 0 1 1 0 1 1 0 8 0 amappl14 176 26 0 21 1 0 1 1 0 8 0 amappl13 168 34 0 30 1 0 1 1 0 8 0 amappl12 160 4 0 1 1 0 1 1 0 8 0 amappl11 152 45 0 36 1 0 1 1 0 8 0 amappl10 144 124 0 120 1 0 1 1 0 8 0 amappl9 136 309 0 308 1 0 1 1 0 8 0 amappl8 128 325 0 283 2 0 2 2 0 8 0 amappl7 120 220 0 208 1 0 1 1 0 8 0 amappl6 112 29 0 24 1 0 1 1 0 8 0 amappl5 104 500 0 488 1 0 1 1 0 8 0 amappl4 96 425 0 396 1 0 1 1 0 8 0 amappl3 88 111 0 104 1 0 1 1 0 8 0 amappl2 80 2577 0 2512 2 0 2 2 0 8 0 amappl1 72 17156 0 16742 23 14 9 17 0 8 0 amappl 80 942 0 903 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 13 0 2 1 0 1 1 0 8 0 uaddrrnd 24 431 0 417 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 431 0 417 1 0 1 1 0 8 0 vmmpekpl 168 6998 0 6971 2 0 2 2 0 8 0 vmmpepl 168 57140 0 55170 124 17 107 113 0 357 21 vmsppl 272 430 0 417 3 1 2 2 0 8 1 pdppl 4096 868 0 834 6 1 5 6 0 8 0 pvpl 32 178055 0 158783 172 4 168 168 0 265 11 pmappl 200 430 0 417 1 0 1 1 0 8 0 extentpl 40 53 0 36 1 0 1 1 0 8 0 phpool 112 258 0 21 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(ffffffff823caafe) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd805e241200,4f4,334,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac2760) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da76648,9,fffffd805e241100,0,0,ffff80001d717280) at tcp_usrreq+0xa54 sosend(fffffd805da76648,0,ffff80001d71de98,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:555 dofilewritev(ffff80001d717280,4,ffff80001d71de98,0,ffff80001d71df80) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d717280,ffff80001d71df30,ffff80001d71df80) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d71e000) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffd48f0, 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(ffffffff823caafe) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd805e241200,4f4,334,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac2760) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da76648,9,fffffd805e241100,0,0,ffff80001d717280) at tcp_usrreq+0xa54 sosend(fffffd805da76648,0,ffff80001d71de98,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:555 dofilewritev(ffff80001d717280,4,ffff80001d71de98,0,ffff80001d71df80) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d717280,ffff80001d71df30,ffff80001d71df80) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d71e000) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffd48f0, count: -10