panic: m_copym0: short mbuf chain Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *101772 14325 0 0x12 0 0 sshd db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff823caa39) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8053904100,2c4,254,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac2540) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da8a4b8,9,fffffd8053904000,0,0,ffff80001d7179d0) at tcp_usrreq+0xa54 sosend(fffffd805da8a4b8,0,ffff80001d6c9e38,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:555 dofilewritev(ffff80001d7179d0,4,ffff80001d6c9e38,0,ffff80001d6c9f20) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d7179d0,ffff80001d6c9ed0,ffff80001d6c9f20) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d6c9fa0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffc7f90, 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(ffffffff823caa39) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8053904100,2c4,254,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac2540) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da8a4b8,9,fffffd8053904000,0,0,ffff80001d7179d0) at tcp_usrreq+0xa54 sosend(fffffd805da8a4b8,0,ffff80001d6c9e38,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:555 dofilewritev(ffff80001d7179d0,4,ffff80001d6c9e38,0,ffff80001d6c9f20) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d7179d0,ffff80001d6c9ed0,ffff80001d6c9f20) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d6c9fa0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffc7f90, count: -10 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff80001d6c9900 rbx 0xffff80001d6c99b0 rdx 0x2 rcx 0 rax 0x1 r8 0xffffffff811c348f kprintf+0x15f r9 0x1 r10 0x2 r11 0xa9e1bb30e8bb817d r12 0x3000000008 r13 0xffff80001d6c9910 r14 0x100 r15 0x1 rip 0xffffffff813bfda8 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff80001d6c98f0 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (sshd) pid=101772 stat=onproc flags process=12 proc=0 pri=24, usrpri=50, nice=20 forw=0xffffffffffffffff, list=0xffff80001d718390,0xffff80001d717290 process=0xffff8000ffff8e78 user=0xffff80001d6c5000, vmspace=0xfffffd806bc0abb0 estcpu=0, cpticks=0, pctcpu=0.0 user=0, sys=0, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 93355 16112 0 0 3 0x14280 nfsidl nfsio 48223 247249 0 0 3 0x14280 nfsidl nfsio 49158 249817 0 0 3 0x14280 nfsidl nfsio 3752 415288 0 0 3 0x14280 nfsidl nfsio 88898 102709 0 0 3 0x14280 nfsidl nfsio 95412 17522 0 0 3 0x14280 nfsidl nfsio 68175 120814 0 0 3 0x14280 nfsidl nfsio 46123 465504 0 0 3 0x14280 nfsidl nfsio 5878 408864 0 0 3 0x14280 nfsidl nfsio 95812 247786 0 0 3 0x14280 nfsidl nfsio 62126 50711 0 0 3 0x14280 nfsidl nfsio 84916 239991 0 0 3 0x14280 nfsidl nfsio 65135 284580 0 0 3 0x14280 nfsidl nfsio 74337 232134 0 0 3 0x14280 nfsidl nfsio 39214 14939 0 0 3 0x14280 nfsidl nfsio 13708 361869 0 0 3 0x14280 nfsidl nfsio 64075 117826 0 0 3 0x14280 nfsidl nfsio 3491 295633 0 0 3 0x14280 nfsidl nfsio 84147 93197 0 0 3 0x14280 nfsidl nfsio 25796 288224 0 0 3 0x14280 nfsidl nfsio 54385 497698 0 0 3 0x14200 bored sosplice 61201 515197 61223 0 2 0x2 syz-executor.0 61223 29922 77370 0 3 0x82 thrsleep syz-fuzzer 61223 281194 77370 0 3 0x4000082 nanosleep syz-fuzzer 61223 373579 77370 0 3 0x4000082 thrsleep syz-fuzzer 61223 33392 77370 0 3 0x4000082 thrsleep syz-fuzzer 61223 455594 77370 0 2 0x4000002 syz-fuzzer 61223 502542 77370 0 3 0x4000082 thrsleep syz-fuzzer 61223 217372 77370 0 3 0x4000082 thrsleep syz-fuzzer 61223 183624 77370 0 3 0x4000082 thrsleep syz-fuzzer 61223 184089 77370 0 3 0x4000082 thrsleep syz-fuzzer 77370 390098 14325 0 3 0x10008a pause ksh *14325 101772 8829 0 7 0x12 sshd 99960 412088 1 0 3 0x100083 ttyin getty 8829 398070 1 0 3 0x80 select sshd 23957 379399 86009 73 3 0x100090 kqread syslogd 86009 86953 1 0 3 0x100082 netio syslogd 41415 334197 1 77 3 0x100090 poll dhclient 25504 337265 1 0 3 0x80 poll dhclient 93038 479698 0 0 3 0x14200 bored smr 59928 72442 0 0 2 0x14200 zerothread 56027 312272 0 0 3 0x14200 aiodoned aiodoned 21596 17773 0 0 3 0x14200 syncer update 20624 373263 0 0 3 0x14200 cleaner cleaner 16674 135369 0 0 3 0x14200 reaper reaper 353 229979 0 0 3 0x14200 pgdaemon pagedaemon 45386 488096 0 0 3 0x14200 bored crynlk 76817 201999 0 0 3 0x14200 bored crypto 57247 149749 0 0 3 0x40014200 acpi0 acpi0 41029 433937 0 0 3 0x14200 bored softnet 22368 15840 0 0 3 0x14200 bored systqmp 22031 110930 0 0 3 0x14200 bored systq 19092 331424 0 0 3 0x40014200 bored softclock 6750 124985 0 0 3 0x40014200 idle0 1 12618 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 6342K 6856K 78643K 11286 0 pcb 13 8K 8K 78643K 71 0 rtable 97 6K 7K 78643K 355 0 ifaddr 75 15K 16K 78643K 137 0 counters 20 16K 16K 78643K 27 0 ioctlops 0 0K 4K 78643K 69 0 iov 0 0K 16K 78643K 59 0 mount 1 1K 1K 78643K 1 0 vnodes 1224 77K 77K 78643K 1418 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 38 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1809 195K 288K 78643K 12938 0 file desc 3 5K 25K 78643K 288 0 sigio 0 0K 0K 78643K 4 0 proc 50 38K 55K 78643K 404 0 subproc 16 1K 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 17 0 in_multi 43 2K 2K 78643K 133 0 ether_multi 1 0K 0K 78643K 8 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 43 201K 201K 78643K 43 0 exec 0 0K 1K 78643K 193 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 119 63K 72K 78643K 1587 0 UVM aobj 19 4K 4K 78643K 19 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 ip6_options 0 0K 0K 78643K 38 0 NDP 12 0K 0K 78643K 34 0 temp 98 3858K 3925K 78643K 11841 0 kqueue 3 4K 12K 78643K 18 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 3 1 0 1 1 0 8 0 rtpcb 80 41 0 39 1 0 1 1 0 8 0 rtentry 112 71 0 40 2 0 2 2 0 8 0 unpcb 120 238 0 227 1 0 1 1 0 8 0 syncache 264 7 0 7 3 2 1 1 0 8 1 tcpqe 32 65 0 65 2 2 0 1 0 8 0 tcpcb 544 89 0 85 1 0 1 1 0 8 0 ipq 40 2 0 2 1 0 1 1 0 8 1 ipqe 40 4 0 4 1 0 1 1 0 8 1 inpcb 296 344 0 337 5 3 2 2 0 8 1 ip6q 72 1 0 1 1 1 0 1 0 8 0 ip6af 40 3 0 3 1 1 0 1 0 8 0 nd6 48 22 0 21 1 0 1 1 0 8 0 pfstscr 40 2 0 1 1 0 1 1 0 8 0 pfosfp 40 1 0 0 1 0 1 1 0 8 0 pfosfpen 112 2 0 0 1 0 1 1 0 8 0 pfrktable 1344 12 0 6 2 1 1 1 0 8 0 pftag 88 6 0 2 1 0 1 1 0 8 0 pfstitem 24 2 0 0 1 0 1 1 0 8 0 pfstkey 112 4 0 2 1 0 1 1 0 8 0 pfstate 328 2 0 1 1 0 1 1 0 8 0 pfrule 1360 25 0 4 3 1 2 2 0 8 0 art_heap8 4096 2 0 0 2 0 2 2 0 8 0 art_heap4 256 226 0 92 13 0 13 13 0 8 4 art_table 32 228 0 92 2 0 2 2 0 8 0 art_node 16 70 0 41 1 0 1 1 0 8 0 sysvmsgpl 40 12 0 4 1 0 1 1 0 8 0 semupl 112 4 0 4 1 1 0 1 0 8 0 semapl 112 32 0 22 1 0 1 1 0 8 0 shmpl 112 17 0 0 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 1812 0 418 88 0 88 88 0 8 0 ffsino 240 1812 0 418 83 0 83 83 0 8 0 nchpl 144 2435 0 864 60 0 60 60 0 8 0 uvmvnodes 72 2002 0 0 37 0 37 37 0 8 0 vnodes 208 2002 0 0 106 0 106 106 0 8 0 namei 1024 6569 0 6569 2 1 1 1 0 8 1 vcpupl 1984 6 0 1 1 0 1 1 0 8 0 vmpool 528 8 0 3 1 0 1 1 0 8 0 pfiaddrpl 120 6 0 0 1 0 1 1 0 8 0 scxspl 192 7216 0 7216 1 0 1 1 0 8 1 plimitpl 152 30 0 24 1 0 1 1 0 8 0 sigapl 424 495 0 448 6 0 6 6 0 8 0 futexpl 56 5951 0 5951 2 1 1 1 0 8 1 knotepl 112 101 0 88 1 0 1 1 0 8 0 kqueuepl 144 31 0 29 1 0 1 1 0 8 0 pipepl 272 118 0 111 2 0 2 2 0 8 1 fdescpl 432 460 0 448 2 0 2 2 0 8 0 filepl 120 2849 0 2777 4 0 4 4 0 8 1 lockfpl 104 181 0 180 1 0 1 1 0 8 0 lockfspl 48 73 0 72 1 0 1 1 0 8 0 sessionpl 112 17 0 8 1 0 1 1 0 8 0 pgrppl 48 23 0 14 1 0 1 1 0 8 0 ucredpl 96 296 0 289 1 0 1 1 0 8 0 zombiepl 144 448 0 448 1 0 1 1 0 8 1 processpl 920 495 0 448 7 0 7 7 0 8 0 procpl 624 856 0 801 5 0 5 5 0 8 0 sosppl 128 2 0 2 1 1 0 1 0 8 0 sockpl 400 623 0 603 5 1 4 4 0 8 1 mcl64k 65536 30 0 30 3 3 0 1 0 8 0 mcl16k 16384 2 0 2 2 1 1 1 0 8 1 mcl12k 12288 10 0 10 2 1 1 1 0 8 1 mcl9k 9216 3 0 3 3 3 0 1 0 8 0 mcl8k 8192 26 0 26 3 2 1 1 0 8 1 mcl4k 4096 35 0 35 3 2 1 1 0 8 1 mcl2k2 2112 2 0 2 2 2 0 1 0 8 0 mcl2k 2048 73694 0 73638 19 11 8 15 0 8 0 mtagpl 96 69 0 38 3 1 2 2 0 8 0 mbufpl 256 118973 0 118743 30 2 28 28 0 8 0 bufpl 280 3991 0 128 276 0 276 276 0 8 0 anonpl 16 58340 0 42108 82 16 66 80 0 107 0 amapchunkpl 152 3066 0 2931 23 17 6 19 0 158 0 amappl16 192 2155 0 1273 52 7 45 51 0 8 0 amappl15 184 1 0 0 1 0 1 1 0 8 0 amappl14 176 26 0 22 1 0 1 1 0 8 0 amappl13 168 157 0 154 1 0 1 1 0 8 0 amappl12 160 129 0 127 2 1 1 1 0 8 0 amappl11 152 45 0 36 1 0 1 1 0 8 0 amappl10 144 146 0 139 1 0 1 1 0 8 0 amappl9 136 373 0 372 1 0 1 1 0 8 0 amappl8 128 308 0 275 3 1 2 2 0 8 0 amappl7 120 242 0 228 1 0 1 1 0 8 0 amappl6 112 23 0 18 1 0 1 1 0 8 0 amappl5 104 399 0 390 1 0 1 1 0 8 0 amappl4 96 421 0 393 1 0 1 1 0 8 0 amappl3 88 114 0 106 1 0 1 1 0 8 0 amappl2 80 3000 0 2944 2 0 2 2 0 8 0 amappl1 72 17903 0 17514 23 14 9 17 0 8 0 amappl 80 1097 0 1058 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 18 0 0 1 0 1 1 0 8 0 uaddrrnd 24 468 0 451 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 468 0 451 1 0 1 1 0 8 0 vmmpekpl 168 7162 0 7136 2 0 2 2 0 8 0 vmmpepl 168 61507 0 59714 121 28 93 115 0 357 7 vmsppl 272 467 0 451 2 0 2 2 0 8 0 pdppl 4096 942 0 907 8 2 6 6 0 8 0 pvpl 32 184060 0 165146 189 26 163 188 0 265 7 pmappl 200 467 0 451 2 0 2 2 0 8 0 extentpl 40 53 0 36 1 0 1 1 0 8 0 phpool 112 279 0 28 8 0 8 8 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(ffffffff823caa39) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8053904100,2c4,254,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac2540) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da8a4b8,9,fffffd8053904000,0,0,ffff80001d7179d0) at tcp_usrreq+0xa54 sosend(fffffd805da8a4b8,0,ffff80001d6c9e38,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:555 dofilewritev(ffff80001d7179d0,4,ffff80001d6c9e38,0,ffff80001d6c9f20) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d7179d0,ffff80001d6c9ed0,ffff80001d6c9f20) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d6c9fa0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffc7f90, 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(ffffffff823caa39) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8053904100,2c4,254,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac2540) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da8a4b8,9,fffffd8053904000,0,0,ffff80001d7179d0) at tcp_usrreq+0xa54 sosend(fffffd805da8a4b8,0,ffff80001d6c9e38,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:555 dofilewritev(ffff80001d7179d0,4,ffff80001d6c9e38,0,ffff80001d6c9f20) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d7179d0,ffff80001d6c9ed0,ffff80001d6c9f20) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d6c9fa0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffc7f90, count: -10