panic: m_copym0: short mbuf chain Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *371504 92818 0 0x12 0 0 sshd db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff823cc2c6) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8064284100,484,464,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac3980) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da73648,9,fffffd8064284000,0,0,ffff80001d71d120) at tcp_usrreq+0xa54 sosend(fffffd805da73648,0,ffff80001d7238b8,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:555 dofilewritev(ffff80001d71d120,4,ffff80001d7238b8,0,ffff80001d7239a0) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d71d120,ffff80001d723950,ffff80001d7239a0) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d723a20) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffe97e0, 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(ffffffff823cc2c6) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8064284100,484,464,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac3980) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da73648,9,fffffd8064284000,0,0,ffff80001d71d120) at tcp_usrreq+0xa54 sosend(fffffd805da73648,0,ffff80001d7238b8,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:555 dofilewritev(ffff80001d71d120,4,ffff80001d7238b8,0,ffff80001d7239a0) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d71d120,ffff80001d723950,ffff80001d7239a0) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d723a20) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffe97e0, count: -10 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff80001d723380 rbx 0xffff80001d723430 rdx 0x2 rcx 0 rax 0x1 r8 0xffffffff813392bf kprintf+0x15f r9 0x1 r10 0x2 r11 0x966532c593d89f9a r12 0x3000000008 r13 0xffff80001d723390 r14 0x100 r15 0x1 rip 0xffffffff81597d08 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff80001d723370 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (sshd) pid=371504 stat=onproc flags process=12 proc=0 pri=24, usrpri=50, nice=20 forw=0xffffffffffffffff, list=0xffff80001d71d870,0xffff80001d71cc50 process=0xffff80001d700af8 user=0xffff80001d71e000, vmspace=0xfffffd806bc0a990 estcpu=0, cpticks=0, pctcpu=0.0 user=0, sys=0, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 14336 290666 44164 0 2 0 syz-executor.0 44164 342292 76359 0 3 0x82 nanosleep syz-executor.0 21221 465995 76359 0 2 0x2 syz-executor.1 76359 501242 59388 0 3 0x82 thrsleep syz-fuzzer 76359 481404 59388 0 2 0x4000002 syz-fuzzer 76359 342591 59388 0 3 0x4000082 thrsleep syz-fuzzer 76359 300509 59388 0 3 0x4000082 thrsleep syz-fuzzer 76359 256262 59388 0 2 0x4000002 syz-fuzzer 76359 139540 59388 0 3 0x4000082 thrsleep syz-fuzzer 76359 338615 59388 0 3 0x4000082 thrsleep syz-fuzzer 59388 408441 92818 0 3 0x10008a pause ksh *92818 371504 6310 0 7 0x12 sshd 60640 202308 1 0 3 0x100083 ttyin getty 6310 344675 1 0 3 0x80 select sshd 7354 479661 74955 73 3 0x100090 kqread syslogd 74955 376140 1 0 3 0x100082 netio syslogd 98080 389300 1 77 3 0x100090 poll dhclient 79030 56887 1 0 3 0x80 poll dhclient 22555 101501 0 0 3 0x14200 bored smr 70631 234671 0 0 2 0x14200 zerothread 46672 423879 0 0 3 0x14200 aiodoned aiodoned 4624 371684 0 0 3 0x14200 syncer update 42588 249443 0 0 3 0x14200 cleaner cleaner 23573 208971 0 0 3 0x14200 reaper reaper 32004 253278 0 0 3 0x14200 pgdaemon pagedaemon 40170 320344 0 0 3 0x14200 bored crynlk 82918 157339 0 0 3 0x14200 bored crypto 24391 244612 0 0 3 0x40014200 acpi0 acpi0 21182 376849 0 0 3 0x14200 bored softnet 28798 40776 0 0 3 0x14200 bored systqmp 65700 332090 0 0 3 0x14200 bored systq 18921 222413 0 0 3 0x40014200 bored softclock 62247 3047 0 0 3 0x40014200 idle0 1 405947 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 9452 6323K 6582K 78643K 10605 0 pcb 13 8K 8K 78643K 19 0 rtable 103 3K 3K 78643K 203 0 ifaddr 39 10K 10K 78643K 43 0 counters 21 16K 16K 78643K 21 0 ioctlops 0 0K 4K 78643K 19 0 iov 0 0K 24K 78643K 6 0 mount 1 1K 1K 78643K 1 0 vnodes 1217 77K 77K 78643K 1234 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 1K 1K 78643K 16 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1809 195K 288K 78643K 12938 0 file desc 5 13K 25K 78643K 77 0 proc 48 38K 54K 78643K 362 0 subproc 32 2K 2K 78643K 34 0 NFS srvsock 1 0K 0K 78643K 1 0 NFS daemon 1 16K 16K 78643K 1 0 in_multi 33 2K 2K 78643K 41 0 ether_multi 1 0K 0K 78643K 1 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 183 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 131 23K 25K 78643K 1037 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 2 0 NDP 6 0K 0K 78643K 11 0 temp 61 3851K 3919K 78643K 2225 0 kqueue 3 4K 8K 78643K 8 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 21 0 19 1 0 1 1 0 8 0 rtentry 112 52 0 9 2 0 2 2 0 8 0 unpcb 120 155 0 147 1 0 1 1 0 8 0 syncache 264 4 0 4 1 1 0 1 0 8 0 tcpqe 32 372 0 372 1 0 1 1 0 8 1 tcpcb 544 20 0 16 1 0 1 1 0 8 0 ipq 40 19 0 18 1 0 1 1 0 8 0 ipqe 40 812 0 811 1 0 1 1 0 8 0 inpcb 296 134 0 127 2 0 2 2 0 8 1 nd6 48 9 0 4 1 0 1 1 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 214 0 42 13 0 13 13 0 8 0 art_table 32 215 0 42 2 0 2 2 0 8 0 art_node 16 51 0 12 1 0 1 1 0 8 0 semupl 112 1 0 1 1 0 1 1 0 8 1 semapl 112 10 0 0 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 1471 0 73 88 0 88 88 0 8 0 ffsino 240 1471 0 73 83 0 83 83 0 8 0 nchpl 144 1753 0 150 60 0 60 60 0 8 0 uvmvnodes 72 1525 0 0 28 0 28 28 0 8 0 vnodes 208 1525 0 0 81 0 81 81 0 8 0 namei 1024 4347 0 4347 1 0 1 1 0 8 1 vmpool 528 2 0 2 1 0 1 1 0 8 1 scxspl 192 5237 0 5237 1 0 1 1 0 8 1 plimitpl 152 15 0 8 1 0 1 1 0 8 0 sigapl 424 263 0 235 4 0 4 4 0 8 0 futexpl 56 1172 0 1172 1 0 1 1 0 8 1 knotepl 112 66 0 47 1 0 1 1 0 8 0 kqueuepl 144 14 0 12 1 0 1 1 0 8 0 pipepl 272 74 0 64 1 0 1 1 0 8 0 fdescpl 432 249 0 235 2 0 2 2 0 8 0 filepl 120 1397 0 1302 4 0 4 4 0 8 1 lockfpl 104 13 0 12 1 0 1 1 0 8 0 lockfspl 48 7 0 6 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 75 0 68 1 0 1 1 0 8 0 zombiepl 144 235 0 235 1 0 1 1 0 8 1 processpl 928 263 0 235 4 0 4 4 0 8 0 procpl 624 325 0 291 4 0 4 4 0 8 1 sockpl 400 312 0 295 4 0 4 4 0 8 2 mcl64k 65536 23 0 23 1 0 1 1 0 8 1 mcl12k 12288 1 0 1 1 0 1 1 0 8 1 mcl8k 8192 4 0 4 1 0 1 1 0 8 1 mcl4k 4096 15 0 15 2 1 1 1 0 8 1 mcl2k 2048 89322 0 89261 27 10 17 21 0 8 8 mtagpl 96 5 0 3 2 1 1 1 0 8 0 mbufpl 256 144965 0 144774 25 2 23 23 0 8 7 bufpl 280 3460 0 126 239 0 239 239 0 8 0 anonpl 16 45273 0 26126 85 2 83 83 0 107 0 amapchunkpl 152 1171 0 1003 7 0 7 7 0 158 0 amappl16 192 1408 0 305 57 0 57 57 0 8 1 amappl15 184 44 0 40 1 0 1 1 0 8 0 amappl14 176 23 0 19 1 0 1 1 0 8 0 amappl13 168 27 0 24 1 0 1 1 0 8 0 amappl12 160 11 0 10 1 0 1 1 0 8 0 amappl11 152 44 0 35 1 0 1 1 0 8 0 amappl10 144 60 0 51 1 0 1 1 0 8 0 amappl9 136 388 0 386 1 0 1 1 0 8 0 amappl8 128 336 0 288 2 0 2 2 0 8 0 amappl7 120 108 0 95 1 0 1 1 0 8 0 amappl6 112 23 0 19 1 0 1 1 0 8 0 amappl5 104 170 0 156 1 0 1 1 0 8 0 amappl4 96 422 0 394 1 0 1 1 0 8 0 amappl3 88 104 0 97 1 0 1 1 0 8 0 amappl2 80 1208 0 1143 2 0 2 2 0 8 0 amappl1 72 14760 0 14355 23 11 12 17 0 8 3 amappl 80 556 0 511 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 24 251 0 237 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 251 0 237 1 0 1 1 0 8 0 vmmpekpl 168 5795 0 5770 2 0 2 2 0 8 0 vmmpepl 168 38148 0 35959 130 6 124 124 0 357 28 vmsppl 272 250 0 237 2 0 2 2 0 8 1 pdppl 4096 508 0 474 6 0 6 6 0 8 1 pvpl 32 146137 0 124038 195 0 195 195 0 265 6 pmappl 200 250 0 237 1 0 1 1 0 8 0 extentpl 40 53 0 36 1 0 1 1 0 8 0 phpool 112 265 0 15 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(ffffffff823cc2c6) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8064284100,484,464,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac3980) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da73648,9,fffffd8064284000,0,0,ffff80001d71d120) at tcp_usrreq+0xa54 sosend(fffffd805da73648,0,ffff80001d7238b8,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:555 dofilewritev(ffff80001d71d120,4,ffff80001d7238b8,0,ffff80001d7239a0) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d71d120,ffff80001d723950,ffff80001d7239a0) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d723a20) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffe97e0, 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(ffffffff823cc2c6) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8064284100,484,464,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac3980) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da73648,9,fffffd8064284000,0,0,ffff80001d71d120) at tcp_usrreq+0xa54 sosend(fffffd805da73648,0,ffff80001d7238b8,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:555 dofilewritev(ffff80001d71d120,4,ffff80001d7238b8,0,ffff80001d7239a0) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d71d120,ffff80001d723950,ffff80001d7239a0) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d723a20) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffe97e0, count: -10