panic: m_copym0: short mbuf chain Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *510043 15640 0 0x12 0 0 sshd db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff821cbd1e) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd806bc22200,504,1fc,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff8000009f4aa0) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805dacb7d8,9,fffffd806bc22100,0,0,ffff80001d797010) at tcp_usrreq+0xa54 sosend(fffffd805dacb7d8,0,ffff80001d749e48,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d797010,4,ffff80001d749e48,0,ffff80001d749f30) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d797010,ffff80001d749ee0,ffff80001d749f30) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d749fb0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffcafd0, 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(ffffffff821cbd1e) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd806bc22200,504,1fc,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff8000009f4aa0) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805dacb7d8,9,fffffd806bc22100,0,0,ffff80001d797010) at tcp_usrreq+0xa54 sosend(fffffd805dacb7d8,0,ffff80001d749e48,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d797010,4,ffff80001d749e48,0,ffff80001d749f30) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d797010,ffff80001d749ee0,ffff80001d749f30) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d749fb0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffcafd0, count: -10 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff80001d749910 rbx 0xffff80001d7499c0 rdx 0x2 rcx 0 rax 0x1 r8 0xffffffff8176a20f kprintf+0x15f r9 0x1 r10 0x2 r11 0xf53cf4e806267923 r12 0x3000000008 r13 0xffff80001d749920 r14 0x100 r15 0x1 rip 0xffffffff8134cc68 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff80001d749900 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (sshd) pid=510043 stat=onproc flags process=12 proc=0 pri=24, usrpri=50, nice=20 forw=0xffffffffffffffff, list=0xffff80001d797760,0xffff80001d7979e0 process=0xffff8000ffff8748 user=0xffff80001d745000, vmspace=0xfffffd806bc0a440 estcpu=0, cpticks=0, pctcpu=0.0 user=0, sys=0, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 20493 199433 62163 0 2 0 syz-executor.0 20493 388713 62163 0 2 0x4000000 syz-executor.0 62163 152621 63647 0 3 0x82 nanosleep syz-executor.0 68758 425129 0 0 3 0x14280 nfsidl nfsio 13496 460214 0 0 3 0x14280 nfsidl nfsio 10625 259686 0 0 3 0x14280 nfsidl nfsio 70926 290818 0 0 3 0x14280 nfsidl nfsio 57415 282435 0 0 3 0x14280 nfsidl nfsio 19501 201708 0 0 3 0x14280 nfsidl nfsio 35999 371106 0 0 3 0x14280 nfsidl nfsio 93008 193452 0 0 3 0x14280 nfsidl nfsio 3942 262071 0 0 3 0x14280 nfsidl nfsio 17528 516090 0 0 3 0x14280 nfsidl nfsio 43722 220155 0 0 3 0x14280 nfsidl nfsio 56451 381844 0 0 3 0x14280 nfsidl nfsio 73808 128715 0 0 3 0x14280 nfsidl nfsio 62354 172689 0 0 3 0x14280 nfsidl nfsio 32825 45476 0 0 3 0x14280 nfsidl nfsio 48800 209463 0 0 3 0x14280 nfsidl nfsio 84997 112045 0 0 3 0x14280 nfsidl nfsio 17123 188296 0 0 3 0x14280 nfsidl nfsio 75438 62221 0 0 3 0x14280 nfsidl nfsio 75961 336721 0 0 3 0x14280 nfsidl nfsio 48192 462864 63647 0 2 0x2 syz-executor.1 15448 21639 0 0 3 0x14200 bored sosplice 63647 426186 85556 0 3 0x82 thrsleep syz-fuzzer 63647 296096 85556 0 2 0x4000002 syz-fuzzer 63647 247521 85556 0 2 0x4000002 syz-fuzzer 63647 104028 85556 0 3 0x4000082 thrsleep syz-fuzzer 63647 485908 85556 0 3 0x4000082 thrsleep syz-fuzzer 63647 237923 85556 0 3 0x4000082 thrsleep syz-fuzzer 63647 483753 85556 0 3 0x4000082 thrsleep syz-fuzzer 63647 407752 85556 0 3 0x4000082 thrsleep syz-fuzzer 85556 167781 15640 0 3 0x10008a pause ksh *15640 510043 50767 0 7 0x12 sshd 62380 109992 1 0 3 0x100083 ttyin getty 50767 328028 1 0 3 0x80 select sshd 99212 308256 11136 73 3 0x100090 kqread syslogd 11136 400711 1 0 3 0x100082 netio syslogd 98985 355297 1 77 3 0x100090 poll dhclient 25178 129982 1 0 3 0x80 poll dhclient 91250 520554 0 0 3 0x14200 bored smr 22558 110345 0 0 2 0x14200 zerothread 81412 391906 0 0 3 0x14200 aiodoned aiodoned 13856 337296 0 0 3 0x14200 syncer update 58847 71349 0 0 3 0x14200 cleaner cleaner 52922 248378 0 0 3 0x14200 reaper reaper 58894 52386 0 0 3 0x14200 pgdaemon pagedaemon 39454 353068 0 0 3 0x14200 bored crynlk 5884 263324 0 0 3 0x14200 bored crypto 7107 358690 0 0 3 0x40014200 acpi0 acpi0 16963 475564 0 0 3 0x14200 bored softnet 34353 319831 0 0 3 0x14200 bored systqmp 97771 327522 0 0 3 0x14200 bored systq 35803 129716 0 0 3 0x40014200 bored softclock 68900 175686 0 0 3 0x40014200 idle0 1 519731 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 9524 6474K 7885K 78643K 12433 0 pcb 13 8K 8K 78643K 79 0 rtable 111 4K 4K 78643K 495 0 ifaddr 81 15K 15K 78643K 172 0 counters 21 16K 17K 78643K 35 0 ioctlops 0 0K 2K 78643K 51 0 iov 0 0K 12K 78643K 62 0 mount 1 1K 1K 78643K 1 0 vnodes 1221 77K 77K 78643K 1735 0 UFS quota 1 32K 32K 78643K 1 0 UFS mount 5 36K 36K 78643K 5 0 shm 2 1K 5K 78643K 5 0 VM map 2 0K 0K 78643K 2 0 sem 12 0K 0K 78643K 67 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1809 195K 288K 78643K 12938 0 file desc 5 13K 25K 78643K 445 0 proc 49 38K 63K 78643K 554 0 subproc 32 2K 2K 78643K 102 0 NFS srvsock 1 0K 0K 78643K 1 0 NFS daemon 1 16K 16K 78643K 1 0 ip_moptions 0 0K 0K 78643K 40 0 in_multi 52 3K 3K 78643K 139 0 ether_multi 1 0K 0K 78643K 14 0 mrt 0 0K 0K 78643K 3 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 273 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 146 121K 121K 78643K 2036 0 UVM aobj 19 4K 4K 78643K 21 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 ip6_options 0 0K 0K 78643K 68 0 NDP 14 0K 0K 78643K 41 0 temp 109 3035K 3099K 78643K 9642 0 kqueue 3 4K 14K 78643K 55 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 18 0 11 1 0 1 1 0 8 0 rtpcb 80 51 0 49 1 0 1 1 0 8 0 rtentry 112 108 0 64 2 0 2 2 0 8 0 unpcb 120 179 0 170 1 0 1 1 0 8 0 syncache 264 6 0 6 2 1 1 1 0 8 1 tcpqe 32 61 0 61 1 1 0 1 0 8 0 tcpcb 544 197 0 193 1 0 1 1 0 8 0 ipq 40 2 0 2 1 1 0 1 0 8 0 ipqe 40 4 0 4 1 1 0 1 0 8 0 inpcb 280 454 0 447 3 1 2 2 0 8 1 rttmr 72 1 0 1 1 1 0 1 0 8 0 nd6 48 19 0 15 1 0 1 1 0 8 0 ppxss 1128 2 0 2 1 1 0 1 0 8 0 art_heap8 4096 2 0 0 2 0 2 2 0 8 0 art_heap4 256 458 0 241 14 0 14 14 0 8 0 art_table 32 460 0 241 2 0 2 2 0 8 0 art_node 16 107 0 66 1 0 1 1 0 8 0 sysvmsgpl 40 8 0 8 1 0 1 1 0 8 1 semupl 112 3 0 3 1 1 0 1 0 8 0 semapl 112 65 0 55 1 0 1 1 0 8 0 shmpl 112 19 0 2 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 1939 0 544 88 0 88 88 0 8 0 ffsino 240 1939 0 544 83 0 83 83 0 8 0 nchpl 144 2848 0 1259 60 0 60 60 0 8 0 uvmvnodes 72 2443 0 0 45 0 45 45 0 8 0 vnodes 208 2443 0 0 129 0 129 129 0 8 0 namei 1024 7921 0 7921 2 1 1 1 0 8 1 vcpupl 1984 10 0 0 2 0 2 2 0 8 0 vmpool 528 14 0 4 1 0 1 1 0 8 0 scsiplug 64 2 0 2 2 1 1 1 0 8 1 scxspl 192 12012 0 12012 1 0 1 1 0 8 1 plimitpl 152 44 0 37 1 0 1 1 0 8 0 sigapl 424 640 0 591 6 0 6 6 0 8 0 futexpl 56 8291 0 8291 2 1 1 1 0 8 1 knotepl 112 203 0 184 1 0 1 1 0 8 0 kqueuepl 144 297 0 295 1 0 1 1 0 8 0 pipelkpl 16 136 0 126 1 0 1 1 0 8 0 pipepl 120 272 0 253 1 0 1 1 0 8 0 fdescpl 432 605 0 591 2 0 2 2 0 8 0 filepl 120 3879 0 3784 5 1 4 4 0 8 1 lockfpl 104 150 0 149 1 0 1 1 0 8 0 lockfspl 48 55 0 54 1 0 1 1 0 8 0 sessionpl 112 21 0 11 1 0 1 1 0 8 0 pgrppl 48 23 0 13 1 0 1 1 0 8 0 ucredpl 96 268 0 261 1 0 1 1 0 8 0 zombiepl 144 591 0 591 1 0 1 1 0 8 1 processpl 920 640 0 591 7 0 7 7 0 8 0 procpl 624 1098 0 1041 5 0 5 5 0 8 0 sosppl 128 11 0 11 2 1 1 1 0 8 1 sockpl 400 685 0 667 4 1 3 4 0 8 0 mcl64k 65536 29 0 29 2 1 1 1 0 8 1 mcl16k 16384 2 0 2 2 1 1 1 0 8 1 mcl12k 12288 5 0 5 2 1 1 1 0 8 1 mcl9k 9216 6 0 6 1 0 1 1 0 8 1 mcl8k 8192 4 0 4 2 1 1 1 0 8 1 mcl4k 4096 39 0 39 2 1 1 1 0 8 1 mcl2k 2048 69625 0 69578 14 7 7 12 0 8 0 mtagpl 80 51 0 24 2 1 1 1 0 8 0 mbufpl 256 113193 0 113048 14 3 11 11 0 8 0 bufpl 280 5641 0 281 383 0 383 383 0 8 0 anonpl 16 88716 0 74400 69 4 65 68 0 107 3 amapchunkpl 152 3896 0 3770 22 3 19 19 0 158 12 amappl16 192 2877 0 2052 54 7 47 54 0 8 4 amappl15 184 1 0 0 1 0 1 1 0 8 0 amappl14 176 295 0 288 1 0 1 1 0 8 0 amappl13 168 126 0 123 1 0 1 1 0 8 0 amappl12 160 238 0 232 2 1 1 1 0 8 0 amappl11 152 60 0 51 1 0 1 1 0 8 0 amappl10 144 23 0 18 1 0 1 1 0 8 0 amappl9 136 382 0 380 1 0 1 1 0 8 0 amappl8 128 414 0 367 2 0 2 2 0 8 0 amappl7 120 141 0 127 1 0 1 1 0 8 0 amappl6 112 31 0 25 1 0 1 1 0 8 0 amappl5 104 365 0 355 1 0 1 1 0 8 0 amappl4 96 706 0 673 1 0 1 1 0 8 0 amappl3 88 310 0 301 1 0 1 1 0 8 0 amappl2 80 3796 0 3733 2 0 2 2 0 8 0 amappl1 72 20955 0 20552 25 16 9 17 0 8 0 amappl 80 1423 0 1378 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 20 0 2 1 0 1 1 0 8 0 uaddrrnd 24 619 0 595 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 619 0 595 1 0 1 1 0 8 0 vmmpekpl 168 7849 0 7809 2 0 2 2 0 8 0 vmmpepl 168 80588 0 78674 148 32 116 133 0 357 28 vmsppl 272 618 0 595 2 0 2 2 0 8 0 pdppl 4096 1244 0 1200 6 0 6 6 0 8 0 pvpl 32 283807 0 266348 271 30 241 271 0 265 93 pmappl 200 618 0 595 2 0 2 2 0 8 0 extentpl 40 53 0 36 1 0 1 1 0 8 0 phpool 112 248 0 18 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(ffffffff821cbd1e) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd806bc22200,504,1fc,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff8000009f4aa0) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805dacb7d8,9,fffffd806bc22100,0,0,ffff80001d797010) at tcp_usrreq+0xa54 sosend(fffffd805dacb7d8,0,ffff80001d749e48,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d797010,4,ffff80001d749e48,0,ffff80001d749f30) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d797010,ffff80001d749ee0,ffff80001d749f30) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d749fb0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffcafd0, 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(ffffffff821cbd1e) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd806bc22200,504,1fc,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff8000009f4aa0) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805dacb7d8,9,fffffd806bc22100,0,0,ffff80001d797010) at tcp_usrreq+0xa54 sosend(fffffd805dacb7d8,0,ffff80001d749e48,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d797010,4,ffff80001d749e48,0,ffff80001d749f30) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d797010,ffff80001d749ee0,ffff80001d749f30) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d749fb0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffcafd0, count: -10