panic: m_copym0: short mbuf chain Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND * 14438 97899 0 0x12 0 0 sshd db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff823cfca4) at panic+0x164 sys/kern/subr_prf.c:218 m_copym(fffffd805310d600,164,114,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac2880) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da6a7d8,9,fffffd805310d500,0,0,ffff80001d71cc40) at tcp_usrreq+0xa54 sosend(fffffd805da6a7d8,0,ffff80001d723478,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:555 dofilewritev(ffff80001d71cc40,4,ffff80001d723478,0,ffff80001d723560) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d71cc40,ffff80001d723510,ffff80001d723560) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d7235e0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffc4520, 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(ffffffff823cfca4) at panic+0x164 sys/kern/subr_prf.c:218 m_copym(fffffd805310d600,164,114,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac2880) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da6a7d8,9,fffffd805310d500,0,0,ffff80001d71cc40) at tcp_usrreq+0xa54 sosend(fffffd805da6a7d8,0,ffff80001d723478,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:555 dofilewritev(ffff80001d71cc40,4,ffff80001d723478,0,ffff80001d723560) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d71cc40,ffff80001d723510,ffff80001d723560) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d7235e0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffc4520, count: -10 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff80001d722f40 rbx 0xffff80001d722ff0 rdx 0x2 rcx 0 rax 0x1 r8 0xffffffff82040b7f kprintf+0x15f r9 0x1 r10 0x2 r11 0xf51aea93cd7e0f91 r12 0x3000000008 r13 0xffff80001d722f50 r14 0x100 r15 0x1 rip 0xffffffff8130eb58 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff80001d722f30 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (sshd) pid=14438 stat=onproc flags process=12 proc=0 pri=24, usrpri=50, nice=20 forw=0xffffffffffffffff, list=0xffff80001d71dae0,0xffff80001d71c770 process=0xffff80001d706758 user=0xffff80001d71e000, vmspace=0xfffffd806bc0a000 estcpu=0, cpticks=0, pctcpu=0.0 user=0, sys=0, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 94733 203480 77028 0 2 0 syz-executor.0 94733 347441 77028 0 2 0x4000000 syz-executor.0 54114 343730 0 0 3 0x14200 bored sosplice 72465 339294 58599 0 2 0x2 syz-executor.1 77028 92871 58599 0 3 0x82 nanosleep syz-executor.0 58599 519652 26765 0 3 0x82 thrsleep syz-fuzzer 58599 65284 26765 0 2 0x4000002 syz-fuzzer 58599 298218 26765 0 3 0x4000082 thrsleep syz-fuzzer 58599 310795 26765 0 3 0x4000082 thrsleep syz-fuzzer 58599 341868 26765 0 3 0x4000082 thrsleep syz-fuzzer 58599 202619 26765 0 2 0x4000002 syz-fuzzer 58599 393954 26765 0 3 0x4000082 thrsleep syz-fuzzer 26765 376711 97899 0 3 0x10008a pause ksh *97899 14438 837 0 7 0x12 sshd 43654 463350 1 0 3 0x100083 ttyin getty 837 76853 1 0 3 0x80 select sshd 38893 66190 54703 73 3 0x100090 kqread syslogd 54703 516430 1 0 3 0x100082 netio syslogd 64915 206190 1 77 3 0x100090 poll dhclient 23849 115669 1 0 3 0x80 poll dhclient 40025 384527 0 0 3 0x14200 bored smr 89323 156368 0 0 2 0x14200 zerothread 99467 241325 0 0 3 0x14200 aiodoned aiodoned 77380 285167 0 0 3 0x14200 syncer update 41096 348988 0 0 3 0x14200 cleaner cleaner 67726 24210 0 0 3 0x14200 reaper reaper 68260 376597 0 0 3 0x14200 pgdaemon pagedaemon 56460 173665 0 0 3 0x14200 bored crynlk 26406 230316 0 0 3 0x14200 bored crypto 93089 485374 0 0 3 0x40014200 acpi0 acpi0 82931 37161 0 0 3 0x14200 bored softnet 86132 129763 0 0 3 0x14200 bored systqmp 82904 193526 0 0 3 0x14200 bored systq 98806 74871 0 0 3 0x40014200 bored softclock 89814 333325 0 0 3 0x40014200 idle0 1 395639 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 9471 6332K 6968K 78643K 11041 0 pcb 13 8K 8K 78643K 77 0 rtable 124 5K 6K 78643K 322 0 ifaddr 57 12K 13K 78643K 120 0 sysctl 2 0K 0K 78643K 2 0 counters 21 16K 16K 78643K 28 0 ioctlops 0 0K 4K 78643K 260 0 iov 0 0K 24K 78643K 26 0 mount 1 1K 1K 78643K 1 0 vnodes 1226 77K 77K 78643K 1393 0 UFS quota 1 32K 32K 78643K 1 0 UFS mount 5 36K 36K 78643K 5 0 shm 2 1K 5K 78643K 4 0 VM map 2 0K 0K 78643K 2 0 sem 12 0K 0K 78643K 80 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1809 195K 288K 78643K 12938 0 file desc 5 13K 25K 78643K 441 0 sigio 0 0K 0K 78643K 12 0 proc 50 38K 54K 78643K 376 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 31 0 in_multi 37 2K 2K 78643K 86 0 ether_multi 1 0K 0K 78643K 13 0 mrt 0 0K 0K 78643K 3 0 ISOFS mount 1 32K 32K 78643K 1 0 MSDOSFS mount 1 16K 16K 78643K 1 0 ttys 49 228K 228K 78643K 49 0 exec 0 0K 1K 78643K 207 0 pfkey data 0 0K 1K 78643K 2 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 128 71K 71K 78643K 1787 0 UVM aobj 5 2K 2K 78643K 5 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 ip6_options 0 0K 0K 78643K 46 0 NDP 9 0K 0K 78643K 25 0 temp 78 3854K 3918K 78643K 7558 0 kqueue 3 4K 8K 78643K 16 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 7 0 0 1 0 1 1 0 8 0 rtpcb 80 29 0 27 1 0 1 1 0 8 0 rtentry 112 56 0 7 2 0 2 2 0 8 0 unpcb 120 125 0 117 1 0 1 1 0 8 0 syncache 264 6 0 6 2 2 0 1 0 8 0 tcpqe 32 125 0 125 1 1 0 1 0 8 0 tcpcb 544 104 0 96 3 2 1 2 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 296 802 0 795 3 1 2 2 0 8 1 nd6 48 12 0 5 1 0 1 1 0 8 0 pkpcb 40 26 0 26 3 2 1 1 0 8 1 pfrktable 1344 26 0 22 1 0 1 1 0 8 0 pftag 88 4 0 4 1 1 0 1 0 8 0 pfrule 1360 14 0 8 1 0 1 1 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 199 0 0 13 0 13 13 0 8 0 art_table 32 200 0 0 2 0 2 2 0 8 0 art_node 16 55 0 11 1 0 1 1 0 8 0 sysvmsgpl 40 9 0 8 2 1 1 1 0 8 0 semupl 112 1 0 1 1 1 0 1 0 8 0 semapl 112 72 0 62 1 0 1 1 0 8 0 shmpl 112 2 0 0 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 1956 0 555 88 0 88 88 0 8 0 ffsino 240 1956 0 555 83 0 83 83 0 8 0 nchpl 144 2713 0 1110 60 0 60 60 0 8 0 uvmvnodes 72 2127 0 0 39 0 39 39 0 8 0 vnodes 208 2127 0 0 112 0 112 112 0 8 0 namei 1024 7387 0 7387 2 1 1 1 0 8 1 vcpupl 1984 6 0 0 1 0 1 1 0 8 0 vmpool 528 6 0 0 1 0 1 1 0 8 0 pfiaddrpl 120 10 0 6 1 0 1 1 0 8 0 scxspl 192 7724 0 7724 1 0 1 1 0 8 1 plimitpl 152 43 0 36 1 0 1 1 0 8 0 sigapl 424 628 0 599 4 0 4 4 0 8 0 futexpl 56 7283 0 7283 2 1 1 1 0 8 1 knotepl 112 73 0 53 1 0 1 1 0 8 0 kqueuepl 144 42 0 39 1 0 1 1 0 8 0 pipepl 272 123 0 112 3 2 1 2 0 8 0 fdescpl 432 613 0 599 2 0 2 2 0 8 0 filepl 120 3545 0 3448 4 0 4 4 0 8 0 lockfpl 104 75 0 74 1 0 1 1 0 8 0 lockfspl 48 30 0 29 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 96 357 0 350 1 0 1 1 0 8 0 zombiepl 144 599 0 599 1 0 1 1 0 8 1 processpl 928 628 0 599 4 0 4 4 0 8 0 procpl 624 1080 0 1044 5 1 4 4 0 8 1 sosppl 128 4 0 4 1 1 0 1 0 8 0 sockpl 400 984 0 967 5 1 4 4 0 8 2 mcl64k 65536 14 0 14 2 1 1 1 0 8 1 mcl16k 16384 1 0 1 1 1 0 1 0 8 0 mcl12k 12288 7 0 7 2 1 1 1 0 8 1 mcl9k 9216 4 0 4 1 1 0 1 0 8 0 mcl8k 8192 11 0 11 2 1 1 1 0 8 1 mcl4k 4096 21 0 21 3 2 1 1 0 8 1 mcl2k2 2112 4 0 4 2 1 1 1 0 8 1 mcl2k 2048 92248 0 92201 19 12 7 15 0 8 0 mtagpl 96 43 0 7 2 1 1 1 0 8 0 mbufpl 256 147975 0 147790 25 9 16 18 0 8 0 bufpl 280 3805 0 126 263 0 263 263 0 8 0 anonpl 16 66226 0 48313 90 17 73 87 0 107 0 amapchunkpl 152 2339 0 2161 10 2 8 10 0 158 0 amappl16 192 2626 0 1677 60 12 48 60 0 8 0 amappl15 184 25 0 23 1 0 1 1 0 8 0 amappl14 176 236 0 229 1 0 1 1 0 8 0 amappl13 168 34 0 30 1 0 1 1 0 8 0 amappl12 160 8 0 7 2 1 1 1 0 8 0 amappl11 152 256 0 245 1 0 1 1 0 8 0 amappl10 144 208 0 204 1 0 1 1 0 8 0 amappl9 136 361 0 359 1 0 1 1 0 8 0 amappl8 128 288 0 261 1 0 1 1 0 8 0 amappl7 120 298 0 285 1 0 1 1 0 8 0 amappl6 112 21 0 17 1 0 1 1 0 8 0 amappl5 104 319 0 307 1 0 1 1 0 8 0 amappl4 96 600 0 572 1 0 1 1 0 8 0 amappl3 88 322 0 314 1 0 1 1 0 8 0 amappl2 80 3714 0 3651 2 0 2 2 0 8 0 amappl1 72 21477 0 21055 23 14 9 17 0 8 0 amappl 80 1312 0 1260 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 4 0 0 1 0 1 1 0 8 0 uaddrrnd 24 619 0 599 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 619 0 599 1 0 1 1 0 8 0 vmmpekpl 168 7171 0 7139 2 0 2 2 0 8 0 vmmpepl 168 78623 0 76569 127 30 97 122 0 357 6 vmsppl 272 618 0 599 2 0 2 2 0 8 0 pdppl 4096 1244 0 1204 7 1 6 6 0 8 0 pvpl 32 210707 0 189932 200 23 177 200 0 265 7 pmappl 200 618 0 599 2 0 2 2 0 8 1 extentpl 40 53 0 36 1 0 1 1 0 8 0 phpool 112 270 0 36 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(ffffffff823cfca4) at panic+0x164 sys/kern/subr_prf.c:218 m_copym(fffffd805310d600,164,114,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac2880) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da6a7d8,9,fffffd805310d500,0,0,ffff80001d71cc40) at tcp_usrreq+0xa54 sosend(fffffd805da6a7d8,0,ffff80001d723478,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:555 dofilewritev(ffff80001d71cc40,4,ffff80001d723478,0,ffff80001d723560) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d71cc40,ffff80001d723510,ffff80001d723560) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d7235e0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffc4520, 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(ffffffff823cfca4) at panic+0x164 sys/kern/subr_prf.c:218 m_copym(fffffd805310d600,164,114,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac2880) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da6a7d8,9,fffffd805310d500,0,0,ffff80001d71cc40) at tcp_usrreq+0xa54 sosend(fffffd805da6a7d8,0,ffff80001d723478,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:555 dofilewritev(ffff80001d71cc40,4,ffff80001d723478,0,ffff80001d723560) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d71cc40,ffff80001d723510,ffff80001d723560) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d7235e0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffc4520, count: -10