panic: m_copym0: short mbuf chain Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *135971 28803 0 0x12 0 0 sshd db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff821cec6e) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8057df8c00,3c4,1a4,2) 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(fffffd805dad0968,9,fffffd8057df8b00,0,0,ffff80001d797760) at tcp_usrreq+0xa54 sosend(fffffd805dad0968,0,ffff80001d768428,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d797760,4,ffff80001d768428,0,ffff80001d768510) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d797760,ffff80001d7684c0,ffff80001d768510) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d768590) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffbb170, 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(ffffffff821cec6e) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8057df8c00,3c4,1a4,2) 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(fffffd805dad0968,9,fffffd8057df8b00,0,0,ffff80001d797760) at tcp_usrreq+0xa54 sosend(fffffd805dad0968,0,ffff80001d768428,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d797760,4,ffff80001d768428,0,ffff80001d768510) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d797760,ffff80001d7684c0,ffff80001d768510) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d768590) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffbb170, count: -10 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff80001d767ef0 rbx 0xffff80001d767fa0 rdx 0x2 rcx 0 rax 0x1 r8 0xffffffff813551ff kprintf+0x15f r9 0x1 r10 0x2 r11 0xfdafba8ca92388c0 r12 0x3000000008 r13 0xffff80001d767f00 r14 0x100 r15 0x1 rip 0xffffffff81d15128 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff80001d767ee0 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (sshd) pid=135971 stat=onproc flags process=12 proc=0 pri=24, usrpri=50, nice=20 forw=0xffffffffffffffff, list=0xffff80001d798390,0xffff80001d797020 process=0xffff8000ffff8748 user=0xffff80001d763000, vmspace=0xfffffd806bc0a660 estcpu=0, cpticks=0, pctcpu=0.0 user=0, sys=0, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 81002 119151 62374 0 2 0 syz-executor.0 81002 293071 62374 0 2 0x4000000 syz-executor.0 62374 88058 25356 0 3 0x82 nanosleep syz-executor.0 37538 375636 25356 0 2 0x2 syz-executor.1 25356 15837 55042 0 3 0x82 thrsleep syz-fuzzer 25356 200961 55042 0 2 0x4000002 syz-fuzzer 25356 325621 55042 0 3 0x4000082 thrsleep syz-fuzzer 25356 510677 55042 0 3 0x4000082 thrsleep syz-fuzzer 25356 473496 55042 0 3 0x4000082 thrsleep syz-fuzzer 25356 324078 55042 0 2 0x4000002 syz-fuzzer 25356 20652 55042 0 3 0x4000082 thrsleep syz-fuzzer 55042 508872 28803 0 3 0x10008a pause ksh *28803 135971 53221 0 7 0x12 sshd 4238 263472 1 0 3 0x100083 ttyin getty 53221 55826 1 0 3 0x80 select sshd 32595 62126 63230 73 3 0x100090 kqread syslogd 63230 481171 1 0 3 0x100082 netio syslogd 50877 295848 1 77 3 0x100090 poll dhclient 68530 429815 1 0 3 0x80 poll dhclient 28729 453592 0 0 3 0x14200 bored smr 92490 47786 0 0 2 0x14200 zerothread 14496 36640 0 0 3 0x14200 aiodoned aiodoned 69461 308647 0 0 3 0x14200 syncer update 86055 112088 0 0 3 0x14200 cleaner cleaner 48429 6522 0 0 3 0x14200 reaper reaper 54491 28118 0 0 3 0x14200 pgdaemon pagedaemon 855 347078 0 0 3 0x14200 bored crynlk 29469 192161 0 0 3 0x14200 bored crypto 58457 14867 0 0 3 0x40014200 acpi0 acpi0 95501 33523 0 0 3 0x14200 bored softnet 42732 367653 0 0 3 0x14200 bored systqmp 5720 454197 0 0 3 0x14200 bored systq 45956 447858 0 0 3 0x40014200 bored softclock 67843 198030 0 0 3 0x40014200 idle0 1 244086 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 9472 6332K 6647K 78643K 10691 0 pcb 13 8K 8K 78643K 65 0 rtable 112 4K 5K 78643K 240 0 ifaddr 59 13K 13K 78643K 81 0 counters 21 16K 16K 78643K 24 0 ioctlops 0 0K 4K 78643K 31 0 iov 0 0K 16K 78643K 8 0 mount 1 1K 1K 78643K 1 0 vnodes 1216 76K 77K 78643K 1259 0 UFS quota 1 32K 32K 78643K 1 0 UFS mount 5 36K 36K 78643K 5 0 shm 2 1K 5K 78643K 3 0 VM map 2 0K 0K 78643K 2 0 sem 12 0K 0K 78643K 30 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1809 195K 288K 78643K 12938 0 file desc 5 13K 21K 78643K 125 0 proc 49 38K 54K 78643K 365 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 14 0 in_multi 47 2K 3K 78643K 62 0 ether_multi 1 0K 0K 78643K 5 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 191 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 109 22K 22K 78643K 1102 0 UVM aobj 7 2K 2K 78643K 8 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 ip6_options 0 0K 0K 78643K 30 0 NDP 8 0K 0K 78643K 15 0 temp 78 3030K 3094K 78643K 2285 0 kqueue 3 4K 4K 78643K 3 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 1 1 0 1 1 0 8 0 rtpcb 80 29 0 27 1 0 1 1 0 8 0 rtentry 112 48 0 4 2 0 2 2 0 8 0 unpcb 120 99 0 91 1 0 1 1 0 8 0 syncache 264 6 0 6 2 1 1 1 0 8 1 tcpqe 32 118 0 118 1 1 0 1 0 8 0 tcpcb 544 52 0 48 1 0 1 1 0 8 0 inpcb 280 150 0 143 2 0 2 2 0 8 1 nd6 48 6 0 0 1 0 1 1 0 8 0 pfrktable 1344 4 0 1 1 0 1 1 0 8 0 pftag 88 2 0 0 1 0 1 1 0 8 0 pfrule 1360 6 0 2 1 0 1 1 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 192 0 2 12 0 12 12 0 8 0 art_table 32 193 0 2 2 0 2 2 0 8 0 art_node 16 47 0 7 1 0 1 1 0 8 0 sysvmsgpl 40 2 0 2 1 0 1 1 0 8 1 semupl 112 2 0 2 1 0 1 1 0 8 1 semapl 112 28 0 18 1 0 1 1 0 8 0 shmpl 112 6 0 1 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 1534 0 137 88 0 88 88 0 8 0 ffsino 240 1534 0 137 83 0 83 83 0 8 0 nchpl 144 1931 0 329 60 0 60 60 0 8 0 uvmvnodes 72 1605 0 0 30 0 30 30 0 8 0 vnodes 208 1605 0 0 85 0 85 85 0 8 0 namei 1024 4810 0 4810 1 0 1 1 0 8 1 pfiaddrpl 120 2 0 0 1 0 1 1 0 8 0 scxspl 192 4848 0 4848 1 0 1 1 0 8 1 plimitpl 152 24 0 17 1 0 1 1 0 8 0 sigapl 424 311 0 283 4 0 4 4 0 8 0 futexpl 56 2085 0 2085 1 0 1 1 0 8 1 knotepl 112 61 0 42 1 0 1 1 0 8 0 kqueuepl 144 8 0 6 1 0 1 1 0 8 0 pipelkpl 16 81 0 71 1 0 1 1 0 8 0 pipepl 120 162 0 143 1 0 1 1 0 8 0 fdescpl 432 297 0 283 2 0 2 2 0 8 0 filepl 120 1666 0 1571 4 0 4 4 0 8 1 lockfpl 104 5 0 4 1 0 1 1 0 8 0 lockfspl 48 3 0 2 1 0 1 1 0 8 0 sessionpl 112 17 0 7 1 0 1 1 0 8 0 pgrppl 48 23 0 13 1 0 1 1 0 8 0 ucredpl 96 113 0 106 1 0 1 1 0 8 0 zombiepl 144 283 0 283 1 0 1 1 0 8 1 processpl 920 311 0 283 4 0 4 4 0 8 0 procpl 624 427 0 392 4 0 4 4 0 8 1 sockpl 400 278 0 261 3 0 3 3 0 8 1 mcl64k 65536 3 0 3 1 0 1 1 0 8 1 mcl12k 12288 3 0 3 1 0 1 1 0 8 1 mcl9k 9216 3 0 3 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 73138 0 73089 16 3 13 14 0 8 6 mtagpl 80 10 0 2 2 1 1 1 0 8 0 mbufpl 256 116585 0 116487 10 1 9 9 0 8 1 bufpl 280 3319 0 126 229 0 229 229 0 8 0 anonpl 16 41698 0 26681 63 2 61 61 0 107 0 amapchunkpl 152 1249 0 1128 6 0 6 6 0 158 0 amappl16 192 1383 0 526 44 0 44 44 0 8 1 amappl15 184 1 0 0 1 0 1 1 0 8 0 amappl14 176 23 0 18 1 0 1 1 0 8 0 amappl13 168 27 0 24 1 0 1 1 0 8 0 amappl12 160 52 0 48 1 0 1 1 0 8 0 amappl11 152 51 0 41 1 0 1 1 0 8 0 amappl10 144 12 0 7 1 0 1 1 0 8 0 amappl9 136 354 0 353 1 0 1 1 0 8 0 amappl8 128 319 0 283 2 0 2 2 0 8 0 amappl7 120 115 0 101 1 0 1 1 0 8 0 amappl6 112 23 0 20 1 0 1 1 0 8 0 amappl5 104 314 0 301 1 0 1 1 0 8 0 amappl4 96 418 0 392 1 0 1 1 0 8 0 amappl3 88 109 0 101 1 0 1 1 0 8 0 amappl2 80 1499 0 1437 2 0 2 2 0 8 0 amappl1 72 15127 0 14719 24 13 11 17 0 8 2 amappl 80 643 0 605 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 7 0 1 1 0 1 1 0 8 0 uaddrrnd 24 297 0 283 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 297 0 283 1 0 1 1 0 8 0 vmmpekpl 168 6166 0 6143 2 0 2 2 0 8 0 vmmpepl 168 42339 0 40414 120 7 113 113 0 357 28 vmsppl 272 296 0 283 2 0 2 2 0 8 1 pdppl 4096 600 0 566 5 0 5 5 0 8 0 pvpl 32 142723 0 124766 150 0 150 150 0 265 4 pmappl 200 296 0 283 1 0 1 1 0 8 0 extentpl 40 53 0 36 1 0 1 1 0 8 0 phpool 112 236 0 7 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(ffffffff821cec6e) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8057df8c00,3c4,1a4,2) 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(fffffd805dad0968,9,fffffd8057df8b00,0,0,ffff80001d797760) at tcp_usrreq+0xa54 sosend(fffffd805dad0968,0,ffff80001d768428,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d797760,4,ffff80001d768428,0,ffff80001d768510) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d797760,ffff80001d7684c0,ffff80001d768510) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d768590) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffbb170, 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(ffffffff821cec6e) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8057df8c00,3c4,1a4,2) 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(fffffd805dad0968,9,fffffd8057df8b00,0,0,ffff80001d797760) at tcp_usrreq+0xa54 sosend(fffffd805dad0968,0,ffff80001d768428,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d797760,4,ffff80001d768428,0,ffff80001d768510) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d797760,ffff80001d7684c0,ffff80001d768510) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d768590) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffbb170, count: -10