panic: m_copym0: short mbuf chain Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *112868 69029 0 0x12 0 0 sshd db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff823cb859) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8058058a00,444,224,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac3760) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da644b8,9,fffffd8058058900,0,0,ffff80001d71c4f0) at tcp_usrreq+0xa54 sosend(fffffd805da644b8,0,ffff80001d6cd198,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:555 dofilewritev(ffff80001d71c4f0,4,ffff80001d6cd198,0,ffff80001d6cd280) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d71c4f0,ffff80001d6cd230,ffff80001d6cd280) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d6cd300) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7fffff2160, 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(ffffffff823cb859) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8058058a00,444,224,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac3760) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da644b8,9,fffffd8058058900,0,0,ffff80001d71c4f0) at tcp_usrreq+0xa54 sosend(fffffd805da644b8,0,ffff80001d6cd198,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:555 dofilewritev(ffff80001d71c4f0,4,ffff80001d6cd198,0,ffff80001d6cd280) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d71c4f0,ffff80001d6cd230,ffff80001d6cd280) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d6cd300) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7fffff2160, count: -10 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff80001d6ccc60 rbx 0xffff80001d6ccd10 rdx 0x2 rcx 0 rax 0x1 r8 0xffffffff8140a10f kprintf+0x15f r9 0x1 r10 0x2 r11 0x41cbe7fa1279699a r12 0x3000000008 r13 0xffff80001d6ccc70 r14 0x100 r15 0x1 rip 0xffffffff814764a8 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff80001d6ccc50 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (sshd) pid=112868 stat=onproc flags process=12 proc=0 pri=24, usrpri=50, nice=20 forw=0xffffffffffffffff, list=0xffff80001d71dae0,0xffff80001d71c020 process=0xffff80001d700018 user=0xffff80001d6c8000, 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 8161 115665 37546 0 2 0 syz-executor.1 8161 39116 37546 0 2 0x4000000 syz-executor.1 63821 109377 0 0 3 0x14200 bored sosplice 95722 41899 0 0 3 0x14200 acct acct 37546 340912 63825 0 3 0x82 nanosleep syz-executor.1 31380 112372 63825 0 2 0x2 syz-executor.0 63825 477971 63987 0 3 0x82 thrsleep syz-fuzzer 63825 203784 63987 0 3 0x4000082 nanosleep syz-fuzzer 63825 243261 63987 0 3 0x4000082 thrsleep syz-fuzzer 63825 237715 63987 0 3 0x4000082 thrsleep syz-fuzzer 63825 110167 63987 0 3 0x4000082 thrsleep syz-fuzzer 63825 271817 63987 0 2 0x4000002 syz-fuzzer 63825 312633 63987 0 3 0x4000082 thrsleep syz-fuzzer 63825 16398 63987 0 3 0x4000082 thrsleep syz-fuzzer 63987 338722 69029 0 3 0x10008a pause ksh *69029 112868 7808 0 7 0x12 sshd 73593 188015 1 0 3 0x100083 ttyin getty 7808 324001 1 0 3 0x80 select sshd 88128 274468 54149 73 3 0x100090 kqread syslogd 54149 466276 1 0 3 0x100082 netio syslogd 63547 459438 1 77 3 0x100090 poll dhclient 78463 204449 1 0 3 0x80 poll dhclient 48605 18835 0 0 3 0x14200 bored smr 77636 341684 0 0 2 0x14200 zerothread 29948 73641 0 0 3 0x14200 aiodoned aiodoned 75419 474745 0 0 3 0x14200 syncer update 20183 242749 0 0 3 0x14200 cleaner cleaner 99162 332486 0 0 3 0x14200 reaper reaper 10112 252316 0 0 3 0x14200 pgdaemon pagedaemon 6590 66990 0 0 3 0x14200 bored crynlk 95209 54407 0 0 3 0x14200 bored crypto 75810 423461 0 0 3 0x40014200 acpi0 acpi0 71425 33745 0 0 3 0x14200 bored softnet 51730 336118 0 0 3 0x14200 bored systqmp 23493 100144 0 0 3 0x14200 bored systq 11698 379596 0 0 3 0x40014200 bored softclock 68411 226621 0 0 3 0x40014200 idle0 1 221623 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 9460 6326K 6461K 78643K 10712 0 pcb 13 8K 8K 78643K 162 0 rtable 103 3K 7K 78643K 566 0 ifaddr 45 11K 12K 78643K 94 0 sysctl 2 0K 0K 78643K 2 0 counters 21 16K 16K 78643K 25 0 ioctlops 0 0K 4K 78643K 43 0 iov 0 0K 12K 78643K 122 0 mount 1 1K 1K 78643K 1 0 vnodes 1217 77K 77K 78643K 1278 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 0K 0K 78643K 52 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1809 195K 288K 78643K 12938 0 file desc 5 13K 25K 78643K 296 0 proc 48 38K 63K 78643K 385 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 16 0 in_multi 36 2K 2K 78643K 74 0 ether_multi 1 0K 0K 78643K 4 0 mrt 0 0K 0K 78643K 183 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 181 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 127 23K 39K 78643K 1501 0 UVM aobj 5 4K 4K 78643K 5 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 ip6_options 0 0K 0K 78643K 24 0 NDP 6 0K 0K 78643K 19 0 temp 78 3861K 3925K 78643K 6932 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 7 0 1 1 0 1 1 0 8 0 rtpcb 80 25 0 23 1 0 1 1 0 8 0 rtentry 112 153 0 111 2 0 2 2 0 8 0 unpcb 120 81 0 73 1 0 1 1 0 8 0 syncache 264 4 0 4 1 1 0 1 0 8 0 tcpqe 32 134 0 134 1 1 0 1 0 8 0 tcpcb 544 44 0 40 1 0 1 1 0 8 0 inpcb 296 418 0 411 2 0 2 2 0 8 1 rttmr 72 90 0 90 1 0 1 1 0 8 1 nd6 48 11 0 7 1 0 1 1 0 8 0 pfrktable 1344 26 0 26 1 0 1 1 0 8 1 pftag 88 4 0 4 1 0 1 1 0 8 1 pfrule 1360 7 0 4 1 0 1 1 0 8 0 art_heap8 4096 2 0 0 2 0 2 2 0 8 0 art_heap4 256 229 0 45 13 0 13 13 0 8 0 art_table 32 231 0 45 2 0 2 2 0 8 0 art_node 16 152 0 113 1 0 1 1 0 8 0 sysvmsgpl 40 4 0 3 1 0 1 1 0 8 0 semapl 112 50 0 40 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 1726 0 330 88 0 88 88 0 8 0 ffsino 240 1726 0 330 83 0 83 83 0 8 0 nchpl 144 2324 0 721 60 0 60 60 0 8 0 uvmvnodes 72 1810 0 0 33 0 33 33 0 8 0 vnodes 208 1810 0 0 96 0 96 96 0 8 0 namei 1024 6069 0 6069 1 0 1 1 0 8 1 vmpool 528 4 0 4 1 0 1 1 0 8 1 pfiaddrpl 120 8 0 8 1 0 1 1 0 8 1 scxspl 192 6558 0 6558 1 0 1 1 0 8 1 plimitpl 152 20 0 13 1 0 1 1 0 8 0 sigapl 424 484 0 454 4 0 4 4 0 8 0 futexpl 56 4648 0 4648 1 0 1 1 0 8 1 knotepl 112 71 0 52 1 0 1 1 0 8 0 kqueuepl 144 20 0 18 1 0 1 1 0 8 0 pipepl 272 88 0 78 1 0 1 1 0 8 0 fdescpl 432 468 0 454 2 0 2 2 0 8 0 filepl 120 2508 0 2413 4 0 4 4 0 8 1 lockfpl 104 38 0 37 1 0 1 1 0 8 0 lockfspl 48 15 0 14 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 96 235 0 228 1 0 1 1 0 8 0 zombiepl 144 454 0 454 1 0 1 1 0 8 1 processpl 928 484 0 454 4 0 4 4 0 8 0 procpl 624 777 0 739 4 0 4 4 0 8 0 sosppl 128 4 0 4 1 1 0 1 0 8 0 sockpl 400 524 0 507 3 0 3 3 0 8 1 mcl64k 65536 2 0 2 1 0 1 1 0 8 1 mcl12k 12288 5 0 5 1 0 1 1 0 8 1 mcl9k 9216 3 0 3 1 0 1 1 0 8 1 mcl8k 8192 6 0 6 1 0 1 1 0 8 1 mcl4k 4096 26 0 26 1 0 1 1 0 8 1 mcl2k2 2112 9 0 9 1 1 0 1 0 8 0 mcl2k 2048 85689 0 85640 16 5 11 14 0 8 4 mtagpl 96 11 0 4 2 1 1 1 0 8 0 mbufpl 256 138111 0 137978 18 3 15 16 0 8 0 bufpl 280 3608 0 129 249 0 249 249 0 8 0 anonpl 16 59263 0 43308 74 1 73 73 0 107 0 amapchunkpl 152 1950 0 1816 8 2 6 8 0 158 0 amappl16 192 1958 0 968 50 0 50 50 0 8 0 amappl15 184 118 0 116 1 0 1 1 0 8 0 amappl14 176 170 0 162 1 0 1 1 0 8 0 amappl13 168 27 0 24 1 0 1 1 0 8 0 amappl12 160 8 0 6 1 0 1 1 0 8 0 amappl11 152 195 0 184 1 0 1 1 0 8 0 amappl10 144 127 0 122 1 0 1 1 0 8 0 amappl9 136 372 0 370 1 0 1 1 0 8 0 amappl8 128 327 0 283 2 0 2 2 0 8 0 amappl7 120 225 0 212 1 0 1 1 0 8 0 amappl6 112 24 0 18 1 0 1 1 0 8 0 amappl5 104 262 0 253 1 0 1 1 0 8 0 amappl4 96 564 0 535 1 0 1 1 0 8 0 amappl3 88 255 0 246 1 0 1 1 0 8 0 amappl2 80 2927 0 2863 2 0 2 2 0 8 0 amappl1 72 19276 0 18868 24 15 9 17 0 8 0 amappl 80 1021 0 980 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 4 0 0 1 0 1 1 0 8 0 uaddrrnd 24 472 0 458 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 472 0 458 1 0 1 1 0 8 0 vmmpekpl 168 6804 0 6780 2 0 2 2 0 8 0 vmmpepl 168 63720 0 61626 116 9 107 110 0 357 15 vmsppl 272 471 0 458 2 0 2 2 0 8 1 pdppl 4096 950 0 916 6 1 5 6 0 8 0 pvpl 32 180891 0 161948 172 0 172 172 0 265 2 pmappl 200 471 0 458 1 0 1 1 0 8 0 extentpl 40 53 0 36 1 0 1 1 0 8 0 phpool 112 247 0 11 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(ffffffff823cb859) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8058058a00,444,224,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac3760) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da644b8,9,fffffd8058058900,0,0,ffff80001d71c4f0) at tcp_usrreq+0xa54 sosend(fffffd805da644b8,0,ffff80001d6cd198,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:555 dofilewritev(ffff80001d71c4f0,4,ffff80001d6cd198,0,ffff80001d6cd280) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d71c4f0,ffff80001d6cd230,ffff80001d6cd280) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d6cd300) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7fffff2160, 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(ffffffff823cb859) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8058058a00,444,224,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac3760) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da644b8,9,fffffd8058058900,0,0,ffff80001d71c4f0) at tcp_usrreq+0xa54 sosend(fffffd805da644b8,0,ffff80001d6cd198,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:555 dofilewritev(ffff80001d71c4f0,4,ffff80001d6cd198,0,ffff80001d6cd280) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d71c4f0,ffff80001d6cd230,ffff80001d6cd280) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d6cd300) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7fffff2160, count: -10