panic: m_copym0: short mbuf chain Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND * 64232 63357 0 0x12 0 0 sshd db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff823ca915) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd805c320500,384,26c,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac1cc0) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da62198,9,fffffd805e12d000,0,0,ffff80001d717eb0) at tcp_usrreq+0xa54 sosend(fffffd805da62198,0,ffff80001d71e188,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:555 dofilewritev(ffff80001d717eb0,4,ffff80001d71e188,0,ffff80001d71e270) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d717eb0,ffff80001d71e220,ffff80001d71e270) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d71e2f0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffd7a40, 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(ffffffff823ca915) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd805c320500,384,26c,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac1cc0) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da62198,9,fffffd805e12d000,0,0,ffff80001d717eb0) at tcp_usrreq+0xa54 sosend(fffffd805da62198,0,ffff80001d71e188,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:555 dofilewritev(ffff80001d717eb0,4,ffff80001d71e188,0,ffff80001d71e270) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d717eb0,ffff80001d71e220,ffff80001d71e270) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d71e2f0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffd7a40, count: -10 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff80001d71dc50 rbx 0xffff80001d71dd00 rdx 0x2 rcx 0 rax 0x1 r8 0xffffffff81e150bf kprintf+0x15f r9 0x1 r10 0x2 r11 0x671427909ae6a02b r12 0x3000000008 r13 0xffff80001d71dc60 r14 0x100 r15 0x1 rip 0xffffffff812acc18 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff80001d71dc40 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (sshd) pid=64232 stat=onproc flags process=12 proc=0 pri=24, usrpri=50, nice=20 forw=0xffffffffffffffff, list=0xffff80001d718600,0xffff80001d717290 process=0xffff8000ffff83b0 user=0xffff80001d719000, vmspace=0xfffffd806bc09aa0 estcpu=0, cpticks=0, pctcpu=0.0 user=0, sys=0, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 54388 172540 42250 0 2 0 syz-executor.0 54388 605 42250 0 2 0x4000000 syz-executor.0 95133 143769 12294 0 2 0x2 syz-executor.1 93356 502654 0 0 3 0x14200 bored sosplice 34810 208956 0 0 3 0x14200 acct acct 42250 279914 12294 0 3 0x82 nanosleep syz-executor.0 12294 118023 13889 0 3 0x82 thrsleep syz-fuzzer 12294 341498 13889 0 2 0x4000482 syz-fuzzer 12294 68720 13889 0 3 0x4000082 thrsleep syz-fuzzer 12294 213848 13889 0 3 0x4000082 thrsleep syz-fuzzer 12294 30830 13889 0 3 0x4000082 thrsleep syz-fuzzer 12294 23764 13889 0 2 0x4000002 syz-fuzzer 12294 209285 13889 0 3 0x4000082 thrsleep syz-fuzzer 12294 203633 13889 0 3 0x4000082 thrsleep syz-fuzzer 13889 416771 63357 0 3 0x10008a pause ksh *63357 64232 69061 0 7 0x12 sshd 58892 184028 1 0 3 0x100083 ttyin getty 69061 72798 1 0 3 0x80 select sshd 19756 402725 47251 73 3 0x100090 kqread syslogd 47251 178605 1 0 3 0x100082 netio syslogd 57205 382948 1 77 3 0x100090 poll dhclient 55163 272566 1 0 3 0x80 poll dhclient 55836 318877 0 0 3 0x14200 bored smr 69727 14956 0 0 2 0x14200 zerothread 89513 86253 0 0 3 0x14200 aiodoned aiodoned 45232 138005 0 0 3 0x14200 syncer update 45633 103581 0 0 3 0x14200 cleaner cleaner 40205 124622 0 0 3 0x14200 reaper reaper 62863 317881 0 0 3 0x14200 pgdaemon pagedaemon 48547 362577 0 0 3 0x14200 bored crynlk 62637 143158 0 0 3 0x14200 bored crypto 29550 10059 0 0 3 0x40014200 acpi0 acpi0 65250 244947 0 0 3 0x14200 bored softnet 5680 374169 0 0 3 0x14200 bored systqmp 18999 455130 0 0 3 0x14200 bored systq 62732 103433 0 0 3 0x40014200 bored softclock 65209 119004 0 0 3 0x40014200 idle0 1 243223 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 9500 6352K 6844K 78643K 11152 0 pcb 13 8K 8K 78643K 61 0 rtable 110 11K 14K 78643K 471 0 ifaddr 68 13K 14K 78643K 163 0 counters 21 16K 16K 78643K 27 0 ioctlops 0 0K 4K 78643K 73 0 iov 0 0K 16K 78643K 53 0 mount 1 1K 1K 78643K 1 0 vnodes 1234 78K 78K 78643K 1460 0 UFS quota 1 32K 32K 78643K 1 0 UFS mount 5 36K 36K 78643K 5 0 shm 2 1K 5K 78643K 6 0 VM map 2 0K 0K 78643K 2 0 sem 12 0K 1K 78643K 52 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1809 195K 288K 78643K 12938 0 file desc 6 17K 25K 78643K 351 0 proc 49 38K 63K 78643K 418 0 subproc 47 2K 3K 78643K 51 0 NFS srvsock 1 0K 0K 78643K 1 0 NFS daemon 1 16K 16K 78643K 1 0 ip_moptions 0 0K 0K 78643K 27 0 in_multi 55 3K 3K 78643K 104 0 ether_multi 1 0K 0K 78643K 6 0 mrt 0 0K 0K 78643K 2 0 ISOFS mount 1 32K 32K 78643K 1 0 MSDOSFS mount 1 16K 16K 78643K 1 0 ttys 67 307K 307K 78643K 67 0 exec 0 0K 1K 78643K 220 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 132 63K 63K 78643K 1683 0 UVM aobj 4 2K 2K 78643K 10 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 ip6_options 0 0K 0K 78643K 26 0 NDP 13 0K 0K 78643K 25 0 temp 108 3853K 3917K 78643K 15995 0 kqueue 4 6K 11K 78643K 25 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 8 0 2 1 0 1 1 0 8 0 rtpcb 80 37 0 35 1 0 1 1 0 8 0 rtentry 112 64 0 20 2 0 2 2 0 8 0 unpcb 120 143 0 135 1 0 1 1 0 8 0 syncache 264 11 0 11 5 5 0 1 0 8 0 tcpqe 32 30 0 30 2 2 0 1 0 8 0 tcpcb 544 175 0 171 1 0 1 1 0 8 0 ipq 40 2 0 2 1 1 0 1 0 8 0 ipqe 40 8 0 8 1 1 0 1 0 8 0 inpcb 296 404 0 397 5 3 2 2 0 8 1 rttmr 72 1 0 1 1 1 0 1 0 8 0 nd6 48 16 0 10 1 0 1 1 0 8 0 pkpcb 40 4 0 4 2 2 0 1 0 8 0 pfrktable 1344 70 0 70 4 3 1 1 0 8 1 pftag 88 22 0 22 4 3 1 1 0 8 1 pfrule 1360 18 0 13 1 0 1 1 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 244 0 53 14 2 12 13 0 8 0 art_table 32 245 0 53 2 0 2 2 0 8 0 art_node 16 63 0 23 1 0 1 1 0 8 0 sysvmsgpl 40 17 0 16 2 1 1 1 0 8 0 semupl 112 1 0 1 1 1 0 1 0 8 0 semapl 112 48 0 38 1 0 1 1 0 8 0 shmpl 112 8 0 6 2 1 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 1944 0 547 88 0 88 88 0 8 0 ffsino 240 1944 0 547 83 0 83 83 0 8 0 nchpl 144 2635 0 1044 60 0 60 60 0 8 0 uvmvnodes 72 2131 0 0 39 0 39 39 0 8 0 vnodes 208 2131 0 0 113 0 113 113 0 8 0 namei 1024 7889 0 7889 3 2 1 1 0 8 1 vcpupl 1984 6 0 0 1 0 1 1 0 8 0 vmpool 528 10 0 4 1 0 1 1 0 8 0 pfiaddrpl 120 20 0 20 4 3 1 1 0 8 1 scsiplug 64 1 0 1 1 1 0 1 0 8 0 scxspl 192 8153 0 8153 1 0 1 1 0 8 1 plimitpl 152 51 0 43 1 0 1 1 0 8 0 sigapl 424 536 0 505 4 0 4 4 0 8 0 futexpl 56 6836 0 6836 3 2 1 1 0 8 1 knotepl 112 107 0 88 1 0 1 1 0 8 0 kqueuepl 144 67 0 59 1 0 1 1 0 8 0 pipepl 272 116 0 106 1 0 1 1 0 8 0 fdescpl 432 520 0 505 2 0 2 2 0 8 0 filepl 120 3628 0 3514 4 0 4 4 0 8 0 lockfpl 104 211 0 210 1 0 1 1 0 8 0 lockfspl 48 73 0 72 1 0 1 1 0 8 0 sessionpl 112 18 0 7 1 0 1 1 0 8 0 pgrppl 48 20 0 9 1 0 1 1 0 8 0 ucredpl 96 866 0 859 1 0 1 1 0 8 0 zombiepl 144 506 0 505 1 0 1 1 0 8 0 processpl 920 536 0 505 5 0 5 5 0 8 0 procpl 624 934 0 895 6 2 4 4 0 8 0 sosppl 128 12 0 12 2 1 1 1 0 8 1 sockpl 400 588 0 571 5 2 3 3 0 8 1 mcl64k 65536 21 0 21 7 6 1 1 0 8 1 mcl16k 16384 1 0 1 1 1 0 1 0 8 0 mcl12k 12288 10 0 10 6 5 1 1 0 8 1 mcl9k 9216 6 0 6 5 5 0 1 0 8 0 mcl8k 8192 11 0 11 3 2 1 1 0 8 1 mcl4k 4096 36 0 36 7 6 1 1 0 8 1 mcl2k2 2112 2 0 2 2 2 0 1 0 8 0 mcl2k 2048 69224 0 69177 15 8 7 12 0 8 0 mtagpl 96 46 0 27 2 1 1 1 0 8 0 mbufpl 256 112461 0 112313 16 6 10 12 0 8 0 bufpl 280 4381 0 132 304 0 304 304 0 8 0 anonpl 16 60281 0 47591 70 2 68 68 0 107 1 amapchunkpl 152 2693 0 2555 22 15 7 20 0 158 0 amappl16 192 2469 0 1547 48 1 47 47 0 8 0 amappl15 184 146 0 143 1 0 1 1 0 8 0 amappl14 176 27 0 21 1 0 1 1 0 8 0 amappl13 168 36 0 30 1 0 1 1 0 8 0 amappl12 160 6 0 5 2 1 1 1 0 8 0 amappl11 152 50 0 41 1 0 1 1 0 8 0 amappl10 144 158 0 151 1 0 1 1 0 8 0 amappl9 136 367 0 366 1 0 1 1 0 8 0 amappl8 128 340 0 302 2 0 2 2 0 8 0 amappl7 120 128 0 116 1 0 1 1 0 8 0 amappl6 112 26 0 18 1 0 1 1 0 8 0 amappl5 104 462 0 449 1 0 1 1 0 8 0 amappl4 96 439 0 410 1 0 1 1 0 8 0 amappl3 88 119 0 114 1 0 1 1 0 8 0 amappl2 80 3411 0 3333 2 0 2 2 0 8 0 amappl1 72 19266 0 18835 28 19 9 17 0 8 0 amappl 80 1175 0 1128 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 9 0 6 1 0 1 1 0 8 0 uaddrrnd 24 530 0 509 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 530 0 509 1 0 1 1 0 8 0 vmmpekpl 168 7341 0 7309 2 0 2 2 0 8 0 vmmpepl 168 67942 0 65834 162 33 129 129 0 357 36 vmsppl 272 529 0 509 2 0 2 2 0 8 0 pdppl 4096 1066 0 1024 7 1 6 6 0 8 0 pvpl 32 193935 0 178204 181 20 161 163 0 265 4 pmappl 200 529 0 509 2 0 2 2 0 8 0 extentpl 40 53 0 36 1 0 1 1 0 8 0 phpool 112 266 0 40 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(ffffffff823ca915) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd805c320500,384,26c,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac1cc0) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da62198,9,fffffd805e12d000,0,0,ffff80001d717eb0) at tcp_usrreq+0xa54 sosend(fffffd805da62198,0,ffff80001d71e188,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:555 dofilewritev(ffff80001d717eb0,4,ffff80001d71e188,0,ffff80001d71e270) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d717eb0,ffff80001d71e220,ffff80001d71e270) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d71e2f0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffd7a40, 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(ffffffff823ca915) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd805c320500,384,26c,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac1cc0) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da62198,9,fffffd805e12d000,0,0,ffff80001d717eb0) at tcp_usrreq+0xa54 sosend(fffffd805da62198,0,ffff80001d71e188,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:555 dofilewritev(ffff80001d717eb0,4,ffff80001d71e188,0,ffff80001d71e270) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d717eb0,ffff80001d71e220,ffff80001d71e270) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d71e2f0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffd7a40, count: -10