panic: m_copym0: short mbuf chain Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *235713 39311 0 0x12 0 0 sshd db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff821cebad) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8053a71300,40c,15c,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(fffffd805dac5968,9,fffffd8053a71200,0,0,ffff80001d797760) at tcp_usrreq+0xa54 sosend(fffffd805dac5968,0,ffff80001d749f08,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d797760,4,ffff80001d749f08,0,ffff80001d749ff0) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d797760,ffff80001d749fa0,ffff80001d749ff0) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d74a070) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffde910, 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(ffffffff821cebad) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8053a71300,40c,15c,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(fffffd805dac5968,9,fffffd8053a71200,0,0,ffff80001d797760) at tcp_usrreq+0xa54 sosend(fffffd805dac5968,0,ffff80001d749f08,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d797760,4,ffff80001d749f08,0,ffff80001d749ff0) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d797760,ffff80001d749fa0,ffff80001d749ff0) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d74a070) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffde910, count: -10 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff80001d7499d0 rbx 0xffff80001d749a80 rdx 0x2 rcx 0 rax 0x1 r8 0xffffffff819e74bf kprintf+0x15f r9 0x1 r10 0x2 r11 0xa95ed4501d5cd468 r12 0x3000000008 r13 0xffff80001d7499e0 r14 0x100 r15 0x1 rip 0xffffffff811c20f8 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff80001d7499c0 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (sshd) pid=235713 stat=onproc flags process=12 proc=0 pri=24, usrpri=50, nice=20 forw=0xffffffffffffffff, list=0xffff80001d798870,0xffff80001d797020 process=0xffff8000ffff8ae0 user=0xffff80001d745000, vmspace=0xfffffd806bc0acc0 estcpu=0, cpticks=0, pctcpu=0.0 user=0, sys=0, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 59893 405980 92864 0 2 0 syz-executor.1 59893 396789 92864 0 2 0x4000000 syz-executor.1 35733 1746 0 0 3 0x14280 nfsidl nfsio 85904 145635 0 0 3 0x14280 nfsidl nfsio 54938 120865 0 0 3 0x14280 nfsidl nfsio 24359 253156 0 0 3 0x14280 nfsidl nfsio 5582 155534 0 0 3 0x14280 nfsidl nfsio 74098 26297 0 0 3 0x14280 nfsidl nfsio 98388 436313 0 0 3 0x14280 nfsidl nfsio 96478 266187 0 0 3 0x14280 nfsidl nfsio 92327 327681 0 0 3 0x14280 nfsidl nfsio 72493 495203 0 0 3 0x14280 nfsidl nfsio 84799 239974 0 0 3 0x14280 nfsidl nfsio 90142 387293 0 0 3 0x14280 nfsidl nfsio 27499 228100 0 0 3 0x14280 nfsidl nfsio 53320 31526 0 0 3 0x14280 nfsidl nfsio 53839 298745 0 0 3 0x14280 nfsidl nfsio 44570 7149 0 0 3 0x14280 nfsidl nfsio 92400 69883 0 0 3 0x14280 nfsidl nfsio 85016 307623 0 0 3 0x14280 nfsidl nfsio 5830 190213 0 0 3 0x14280 nfsidl nfsio 24091 244577 0 0 3 0x14280 nfsidl nfsio 45723 210751 0 0 3 0x14200 bored sosplice 92864 105237 21962 0 3 0x82 nanosleep syz-executor.1 17021 351018 21962 0 2 0x2 syz-executor.0 21962 322219 37526 0 3 0x82 thrsleep syz-fuzzer 21962 158366 37526 0 2 0x4000002 syz-fuzzer 21962 200116 37526 0 3 0x4000082 thrsleep syz-fuzzer 21962 161994 37526 0 3 0x4000082 thrsleep syz-fuzzer 21962 236874 37526 0 3 0x4000082 thrsleep syz-fuzzer 21962 191236 37526 0 2 0x4000002 syz-fuzzer 21962 119983 37526 0 3 0x4000082 thrsleep syz-fuzzer 37526 168800 39311 0 3 0x10008a pause ksh *39311 235713 70347 0 7 0x12 sshd 93225 290654 1 0 3 0x100083 ttyin getty 70347 37507 1 0 3 0x80 select sshd 6647 4567 3264 73 3 0x100090 kqread syslogd 3264 397663 1 0 3 0x100082 netio syslogd 20978 497745 1 77 3 0x100090 poll dhclient 42270 210495 1 0 3 0x80 poll dhclient 92368 150467 0 0 3 0x14200 bored smr 31997 354203 0 0 2 0x14200 zerothread 45140 385953 0 0 3 0x14200 aiodoned aiodoned 41130 369820 0 0 3 0x14200 syncer update 71712 72370 0 0 3 0x14200 cleaner cleaner 95219 210263 0 0 3 0x14200 reaper reaper 29196 269384 0 0 3 0x14200 pgdaemon pagedaemon 66657 359484 0 0 3 0x14200 bored crynlk 22326 515304 0 0 3 0x14200 bored crypto 38048 155614 0 0 3 0x40014200 acpi0 acpi0 1190 146315 0 0 3 0x14200 bored softnet 52200 383067 0 0 3 0x14200 bored systqmp 28932 218512 0 0 3 0x14200 bored systq 53160 436664 0 0 3 0x40014200 bored softclock 10950 382279 0 0 3 0x40014200 idle0 1 243879 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 9485 6462K 6592K 78643K 10798 0 pcb 13 8K 8K 78643K 47 0 rtable 104 4K 4K 78643K 276 0 ifaddr 57 12K 13K 78643K 62 0 counters 21 16K 16K 78643K 21 0 ioctlops 0 0K 4K 78643K 32 0 iov 0 0K 16K 78643K 28 0 mount 1 1K 1K 78643K 1 0 vnodes 1223 77K 77K 78643K 1319 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 25K 78643K 175 0 proc 50 38K 63K 78643K 387 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 12 0 in_multi 42 2K 2K 78643K 70 0 ether_multi 1 0K 0K 78643K 7 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 202 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 125 55K 64K 78643K 1268 0 UVM aobj 2 2K 2K 78643K 4 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 ip6_options 0 0K 0K 78643K 20 0 NDP 8 0K 0K 78643K 13 0 temp 78 3030K 3094K 78643K 5630 0 kqueue 3 4K 8K 78643K 10 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 80 115 0 113 1 0 1 1 0 8 0 rtentry 112 49 0 8 2 0 2 2 0 8 0 unpcb 120 75 0 67 1 0 1 1 0 8 0 syncache 264 8 0 8 3 3 0 1 0 8 0 tcpqe 32 117 0 117 2 2 0 1 0 8 0 tcpcb 544 76 0 71 1 0 1 1 0 8 0 inpcb 280 168 0 160 2 1 1 2 0 8 0 nd6 48 7 0 3 1 0 1 1 0 8 0 pkpcb 40 2 0 2 1 1 0 1 0 8 0 pfrktable 1344 3 0 1 1 0 1 1 0 8 0 pftag 88 2 0 2 1 1 0 1 0 8 0 pfstitem 24 1 0 0 1 0 1 1 0 8 0 pfstkey 112 2 0 1 1 0 1 1 0 8 0 pfstate 328 2 0 1 1 0 1 1 0 8 0 pfrule 1360 5 0 3 1 0 1 1 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 213 0 40 13 0 13 13 0 8 0 art_table 32 214 0 40 2 0 2 2 0 8 0 art_node 16 48 0 10 1 0 1 1 0 8 0 semupl 112 3 0 3 1 1 0 1 0 8 0 semapl 112 26 0 16 1 0 1 1 0 8 0 shmpl 112 2 0 2 1 1 0 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 1641 0 242 88 0 88 88 0 8 0 ffsino 240 1641 0 242 83 0 83 83 0 8 0 nchpl 144 2082 0 479 60 0 60 60 0 8 0 uvmvnodes 72 1741 0 0 32 0 32 32 0 8 0 vnodes 208 1741 0 0 92 0 92 92 0 8 0 namei 1024 5636 0 5635 1 0 1 1 0 8 0 vcpupl 1984 4 0 0 1 0 1 1 0 8 0 vmpool 528 4 0 0 1 0 1 1 0 8 0 pfiaddrpl 120 2 0 0 1 0 1 1 0 8 0 scxspl 192 5728 0 5728 1 0 1 1 0 8 1 plimitpl 152 24 0 17 1 0 1 1 0 8 0 sigapl 424 382 0 333 6 0 6 6 0 8 0 futexpl 56 3404 0 3404 1 0 1 1 0 8 1 knotepl 112 69 0 50 1 0 1 1 0 8 0 kqueuepl 144 26 0 24 1 0 1 1 0 8 0 pipelkpl 16 96 0 86 1 0 1 1 0 8 0 pipepl 120 192 0 173 1 0 1 1 0 8 0 fdescpl 432 347 0 333 2 0 2 2 0 8 0 filepl 120 2199 0 2103 4 0 4 4 0 8 1 lockfpl 104 52 0 51 1 0 1 1 0 8 0 lockfspl 48 18 0 17 1 0 1 1 0 8 0 sessionpl 112 17 0 7 1 0 1 1 0 8 0 pgrppl 48 21 0 11 1 0 1 1 0 8 0 ucredpl 96 471 0 464 1 0 1 1 0 8 0 zombiepl 144 333 0 333 1 0 1 1 0 8 1 processpl 920 382 0 333 7 0 7 7 0 8 0 procpl 624 570 0 514 6 1 5 5 0 8 0 sosppl 128 2 0 2 1 1 0 1 0 8 0 sockpl 400 360 0 342 3 0 3 3 0 8 1 mcl64k 65536 4 0 4 1 1 0 1 0 8 0 mcl16k 16384 3 0 3 1 1 0 1 0 8 0 mcl12k 12288 3 0 3 2 1 1 1 0 8 1 mcl9k 9216 1 0 1 1 1 0 1 0 8 0 mcl8k 8192 7 0 7 2 1 1 1 0 8 1 mcl4k 4096 21 0 21 3 2 1 1 0 8 1 mcl2k 2048 73080 0 73040 12 6 6 12 0 8 0 mtagpl 80 24 0 5 2 1 1 1 0 8 0 mbufpl 256 117377 0 117130 17 0 17 17 0 8 0 bufpl 280 3689 0 126 255 0 255 255 0 8 0 anonpl 16 52426 0 37002 75 12 63 74 0 107 0 amapchunkpl 152 1653 0 1517 13 7 6 11 0 158 0 amappl16 192 1696 0 844 51 8 43 51 0 8 0 amappl15 184 1 0 0 1 0 1 1 0 8 0 amappl14 176 102 0 96 1 0 1 1 0 8 0 amappl13 168 156 0 151 1 0 1 1 0 8 0 amappl12 160 86 0 82 2 1 1 1 0 8 0 amappl11 152 46 0 37 1 0 1 1 0 8 0 amappl10 144 15 0 9 1 0 1 1 0 8 0 amappl9 136 365 0 364 1 0 1 1 0 8 0 amappl8 128 322 0 284 2 0 2 2 0 8 0 amappl7 120 107 0 95 1 0 1 1 0 8 0 amappl6 112 26 0 22 1 0 1 1 0 8 0 amappl5 104 160 0 150 1 0 1 1 0 8 0 amappl4 96 575 0 541 1 0 1 1 0 8 0 amappl3 88 256 0 246 1 0 1 1 0 8 0 amappl2 80 1950 0 1886 2 0 2 2 0 8 0 amappl1 72 15881 0 15469 24 15 9 17 0 8 0 amappl 80 786 0 743 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 3 0 2 1 0 1 1 0 8 0 uaddrrnd 24 351 0 333 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 351 0 333 1 0 1 1 0 8 0 vmmpekpl 168 6510 0 6475 2 0 2 2 0 8 0 vmmpepl 168 48413 0 46460 112 21 91 106 0 357 4 vmsppl 272 350 0 333 2 0 2 2 0 8 0 pdppl 4096 708 0 670 7 1 6 6 0 8 1 pvpl 32 162663 0 144428 180 13 167 180 0 265 19 pmappl 200 350 0 333 1 0 1 1 0 8 0 extentpl 40 53 0 36 1 0 1 1 0 8 0 phpool 112 247 0 15 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(ffffffff821cebad) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8053a71300,40c,15c,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(fffffd805dac5968,9,fffffd8053a71200,0,0,ffff80001d797760) at tcp_usrreq+0xa54 sosend(fffffd805dac5968,0,ffff80001d749f08,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d797760,4,ffff80001d749f08,0,ffff80001d749ff0) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d797760,ffff80001d749fa0,ffff80001d749ff0) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d74a070) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffde910, 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(ffffffff821cebad) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8053a71300,40c,15c,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(fffffd805dac5968,9,fffffd8053a71200,0,0,ffff80001d797760) at tcp_usrreq+0xa54 sosend(fffffd805dac5968,0,ffff80001d749f08,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d797760,4,ffff80001d749f08,0,ffff80001d749ff0) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d797760,ffff80001d749fa0,ffff80001d749ff0) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d74a070) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffde910, count: -10