panic: m_copym0: short mbuf chain Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *430605 49824 0 0x12 0 0 sshd db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff823c9ac9) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8058ff4f00,25c,254,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac2ee0) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da70328,9,fffffd8058ff4e00,0,0,ffff80001d71c9d0) at tcp_usrreq+0xa54 sosend(fffffd805da70328,0,ffff80001d723238,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:555 dofilewritev(ffff80001d71c9d0,4,ffff80001d723238,0,ffff80001d723320) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d71c9d0,ffff80001d7232d0,ffff80001d723320) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d7233a0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffb8270, 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(ffffffff823c9ac9) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8058ff4f00,25c,254,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac2ee0) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da70328,9,fffffd8058ff4e00,0,0,ffff80001d71c9d0) at tcp_usrreq+0xa54 sosend(fffffd805da70328,0,ffff80001d723238,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:555 dofilewritev(ffff80001d71c9d0,4,ffff80001d723238,0,ffff80001d723320) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d71c9d0,ffff80001d7232d0,ffff80001d723320) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d7233a0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffb8270, count: -10 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff80001d722d00 rbx 0xffff80001d722db0 rdx 0x2 rcx 0 rax 0x1 r8 0xffffffff81f9c19f kprintf+0x15f r9 0x1 r10 0x2 r11 0x2d5327f09a41c5e4 r12 0x3000000008 r13 0xffff80001d722d10 r14 0x100 r15 0x1 rip 0xffffffff820d2968 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff80001d722cf0 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (sshd) pid=430605 stat=onproc flags process=12 proc=0 pri=24, usrpri=50, nice=20 forw=0xffffffffffffffff, list=0xffff80001d71d870,0xffff80001d71c020 process=0xffff80001d701238 user=0xffff80001d71e000, vmspace=0xfffffd806bc0a330 estcpu=0, cpticks=0, pctcpu=0.0 user=0, sys=0, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 98285 339372 84967 0 2 0 syz-executor.0 98285 352227 84967 0 2 0x4000000 syz-executor.0 39572 115107 0 0 3 0x14200 bored sosplice 83433 448424 98607 0 2 0x2 syz-executor.1 84967 446538 98607 0 2 0x482 syz-executor.0 98607 2110 10799 0 3 0x82 thrsleep syz-fuzzer 98607 77806 10799 0 2 0x4000482 syz-fuzzer 98607 159432 10799 0 3 0x4000082 thrsleep syz-fuzzer 98607 455613 10799 0 3 0x4000082 thrsleep syz-fuzzer 98607 209307 10799 0 3 0x4000082 thrsleep syz-fuzzer 98607 273842 10799 0 3 0x4000082 thrsleep syz-fuzzer 98607 359301 10799 0 3 0x4000082 thrsleep syz-fuzzer 98607 104267 10799 0 2 0x4000002 syz-fuzzer 10799 521539 49824 0 3 0x10008a pause ksh *49824 430605 44311 0 7 0x12 sshd 42454 85769 1 0 3 0x100083 ttyin getty 44311 515525 1 0 3 0x80 select sshd 32160 368249 52947 73 3 0x100090 kqread syslogd 52947 172912 1 0 3 0x100082 netio syslogd 53595 184151 1 77 3 0x100090 poll dhclient 62439 105858 1 0 3 0x80 poll dhclient 50359 83969 0 0 3 0x14200 bored smr 20296 101199 0 0 2 0x14200 zerothread 73206 111410 0 0 3 0x14200 aiodoned aiodoned 19479 292145 0 0 3 0x14200 syncer update 66275 42910 0 0 3 0x14200 cleaner cleaner 84997 413374 0 0 3 0x14200 reaper reaper 76792 271643 0 0 3 0x14200 pgdaemon pagedaemon 62022 460757 0 0 3 0x14200 bored crynlk 87764 242282 0 0 3 0x14200 bored crypto 68082 228703 0 0 3 0x40014200 acpi0 acpi0 97854 199109 0 0 3 0x14200 bored softnet 63505 485284 0 0 3 0x14200 bored systqmp 47680 74147 0 0 3 0x14200 bored systq 93848 419179 0 0 3 0x40014200 bored softclock 60327 476911 0 0 3 0x40014200 idle0 1 99912 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 9483 6469K 6598K 78643K 10736 0 pcb 13 8K 8K 78643K 29 0 rtable 96 3K 4K 78643K 220 0 ifaddr 58 13K 13K 78643K 69 0 counters 21 16K 16K 78643K 22 0 ioctlops 0 0K 4K 78643K 25 0 iov 0 0K 12K 78643K 16 0 mount 1 1K 1K 78643K 1 0 vnodes 1218 77K 77K 78643K 1258 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 1K 78643K 25 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1809 195K 288K 78643K 12938 0 file desc 5 13K 25K 78643K 116 0 proc 49 38K 54K 78643K 370 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 1 0 in_multi 44 2K 2K 78643K 52 0 ether_multi 1 0K 0K 78643K 2 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 189 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 118 38K 43K 78643K 1098 0 UVM aobj 20 4K 4K 78643K 20 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 ip6_options 0 0K 0K 78643K 9 0 NDP 8 0K 0K 78643K 14 0 temp 77 3850K 3917K 78643K 9329 0 kqueue 3 4K 8K 78643K 7 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 27 0 25 1 0 1 1 0 8 0 rtentry 112 47 0 10 2 0 2 2 0 8 0 unpcb 120 59 0 51 1 0 1 1 0 8 0 syncache 264 6 0 6 2 1 1 1 0 8 1 tcpqe 32 267 0 267 1 0 1 1 0 8 1 tcpcb 544 32 0 28 1 0 1 1 0 8 0 inpcb 296 97 0 90 2 0 2 2 0 8 1 nd6 48 7 0 0 1 0 1 1 0 8 0 pfrktable 1344 3 0 1 1 0 1 1 0 8 0 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 2 0 0 1 0 1 1 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 189 0 10 12 0 12 12 0 8 0 art_table 32 190 0 10 2 0 2 2 0 8 0 art_node 16 46 0 15 1 0 1 1 0 8 0 semapl 112 21 0 11 1 0 1 1 0 8 0 shmpl 112 17 0 0 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 1521 0 123 88 0 88 88 0 8 0 ffsino 240 1521 0 123 83 0 83 83 0 8 0 nchpl 144 1905 0 302 60 0 60 60 0 8 0 uvmvnodes 72 1594 0 0 29 0 29 29 0 8 0 vnodes 208 1594 0 0 84 0 84 84 0 8 0 namei 1024 4748 0 4748 1 0 1 1 0 8 1 vcpupl 1984 2 0 0 1 0 1 1 0 8 0 vmpool 528 2 0 0 1 0 1 1 0 8 0 pfiaddrpl 120 2 0 0 1 0 1 1 0 8 0 scxspl 192 5188 0 5188 1 0 1 1 0 8 1 plimitpl 152 20 0 13 1 0 1 1 0 8 0 sigapl 424 303 0 274 4 0 4 4 0 8 0 futexpl 56 1697 0 1697 1 0 1 1 0 8 1 knotepl 112 65 0 46 1 0 1 1 0 8 0 kqueuepl 144 16 0 14 1 0 1 1 0 8 0 pipepl 272 78 0 68 1 0 1 1 0 8 0 fdescpl 432 288 0 274 2 0 2 2 0 8 0 filepl 120 1509 0 1414 4 0 4 4 0 8 1 lockfpl 104 27 0 26 1 0 1 1 0 8 0 lockfspl 48 10 0 9 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 99 0 92 1 0 1 1 0 8 0 zombiepl 144 274 0 274 1 0 1 1 0 8 1 processpl 928 303 0 274 4 0 4 4 0 8 0 procpl 624 403 0 366 4 0 4 4 0 8 1 sockpl 400 183 0 166 3 0 3 3 0 8 1 mcl64k 65536 11 0 11 1 0 1 1 0 8 1 mcl12k 12288 5 0 5 1 0 1 1 0 8 1 mcl9k 9216 4 0 4 1 0 1 1 0 8 1 mcl8k 8192 3 0 3 1 0 1 1 0 8 1 mcl4k 4096 15 0 15 2 1 1 1 0 8 1 mcl2k 2048 77631 0 77585 16 1 15 15 0 8 8 mtagpl 96 20 0 2 2 1 1 1 0 8 0 mbufpl 256 123700 0 123577 11 0 11 11 0 8 2 bufpl 280 3463 0 126 239 0 239 239 0 8 0 anonpl 16 45935 0 29966 83 2 81 81 0 107 16 amapchunkpl 152 1358 0 1227 8 0 8 8 0 158 2 amappl16 192 1562 0 685 57 0 57 57 0 8 12 amappl15 184 2 0 0 1 0 1 1 0 8 0 amappl14 176 65 0 60 1 0 1 1 0 8 0 amappl13 168 26 0 23 1 0 1 1 0 8 0 amappl12 160 54 0 51 1 0 1 1 0 8 0 amappl11 152 52 0 42 1 0 1 1 0 8 0 amappl10 144 12 0 7 1 0 1 1 0 8 0 amappl9 136 358 0 356 1 0 1 1 0 8 0 amappl8 128 314 0 280 2 0 2 2 0 8 0 amappl7 120 106 0 94 1 0 1 1 0 8 0 amappl6 112 25 0 20 1 0 1 1 0 8 0 amappl5 104 312 0 300 1 0 1 1 0 8 0 amappl4 96 417 0 393 1 0 1 1 0 8 0 amappl3 88 149 0 144 1 0 1 1 0 8 0 amappl2 80 1482 0 1417 2 0 2 2 0 8 0 amappl1 72 14546 0 14133 22 9 13 17 0 8 3 amappl 80 625 0 584 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 19 0 0 1 0 1 1 0 8 0 uaddrrnd 24 290 0 274 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 290 0 274 1 0 1 1 0 8 0 vmmpekpl 168 5948 0 5919 2 0 2 2 0 8 0 vmmpepl 168 42278 0 40313 115 4 111 111 0 357 24 vmsppl 272 289 0 274 2 0 2 2 0 8 0 pdppl 4096 586 0 550 6 0 6 6 0 8 1 pvpl 32 146597 0 127670 191 0 191 191 0 265 37 pmappl 200 289 0 274 1 0 1 1 0 8 0 extentpl 40 53 0 36 1 0 1 1 0 8 0 phpool 112 239 0 4 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(ffffffff823c9ac9) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8058ff4f00,25c,254,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac2ee0) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da70328,9,fffffd8058ff4e00,0,0,ffff80001d71c9d0) at tcp_usrreq+0xa54 sosend(fffffd805da70328,0,ffff80001d723238,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:555 dofilewritev(ffff80001d71c9d0,4,ffff80001d723238,0,ffff80001d723320) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d71c9d0,ffff80001d7232d0,ffff80001d723320) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d7233a0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffb8270, 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(ffffffff823c9ac9) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8058ff4f00,25c,254,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac2ee0) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da70328,9,fffffd8058ff4e00,0,0,ffff80001d71c9d0) at tcp_usrreq+0xa54 sosend(fffffd805da70328,0,ffff80001d723238,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:555 dofilewritev(ffff80001d71c9d0,4,ffff80001d723238,0,ffff80001d723320) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d71c9d0,ffff80001d7232d0,ffff80001d723320) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d7233a0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffb8270, count: -10