panic: m_copym0: short mbuf chain Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *490120 40739 0 0x12 0 0 sshd db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff821cf907) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd806b46d500,26c,184,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff8000009f5760) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805dabe4b8,9,fffffd806b46d400,0,0,ffff80001d797eb0) at tcp_usrreq+0xa54 sosend(fffffd805dabe4b8,0,ffff80001d79e7c8,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d797eb0,4,ffff80001d79e7c8,0,ffff80001d79e8b0) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d797eb0,ffff80001d79e860,ffff80001d79e8b0) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d79e930) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffdeb90, 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(ffffffff821cf907) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd806b46d500,26c,184,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff8000009f5760) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805dabe4b8,9,fffffd806b46d400,0,0,ffff80001d797eb0) at tcp_usrreq+0xa54 sosend(fffffd805dabe4b8,0,ffff80001d79e7c8,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d797eb0,4,ffff80001d79e7c8,0,ffff80001d79e8b0) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d797eb0,ffff80001d79e860,ffff80001d79e8b0) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d79e930) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffdeb90, count: -10 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff80001d79e290 rbx 0xffff80001d79e340 rdx 0x2 rcx 0 rax 0x1 r8 0xffffffff8160215f kprintf+0x15f r9 0x1 r10 0x2 r11 0x6de34a58e298afcc r12 0x3000000008 r13 0xffff80001d79e2a0 r14 0x100 r15 0x1 rip 0xffffffff81470708 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff80001d79e280 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (sshd) pid=490120 stat=onproc flags process=12 proc=0 pri=24, usrpri=50, nice=20 forw=0xffffffffffffffff, list=0xffff80001d798870,0xffff80001d7979e0 process=0xffff8000ffff8018 user=0xffff80001d799000, 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 20366 462910 36365 0 2 0x2 syz-executor.0 4996 406984 0 0 3 0x14200 bored sosplice 33602 464879 36365 0 2 0x2 syz-executor.1 36365 430057 7920 0 3 0x82 thrsleep syz-fuzzer 36365 509210 7920 0 2 0x4000002 syz-fuzzer 36365 214074 7920 0 3 0x4000082 thrsleep syz-fuzzer 36365 256768 7920 0 3 0x4000082 thrsleep syz-fuzzer 36365 364525 7920 0 3 0x4000082 thrsleep syz-fuzzer 36365 80063 7920 0 2 0x4000002 syz-fuzzer 36365 21467 7920 0 3 0x4000082 thrsleep syz-fuzzer 7920 333883 40739 0 3 0x10008a pause ksh *40739 490120 91247 0 7 0x12 sshd 82279 478233 1 0 3 0x100083 ttyin getty 91247 366386 1 0 3 0x80 select sshd 30745 248348 37809 73 3 0x100090 kqread syslogd 37809 41415 1 0 3 0x100082 netio syslogd 65316 487380 1 77 3 0x100090 poll dhclient 81377 205795 1 0 3 0x80 poll dhclient 11879 341852 0 0 3 0x14200 bored smr 47511 2243 0 0 2 0x14200 zerothread 2046 238374 0 0 3 0x14200 aiodoned aiodoned 45493 456081 0 0 3 0x14200 syncer update 61380 135107 0 0 3 0x14200 cleaner cleaner 99764 435670 0 0 3 0x14200 reaper reaper 72730 167407 0 0 3 0x14200 pgdaemon pagedaemon 88908 320287 0 0 3 0x14200 bored crynlk 30001 186992 0 0 3 0x14200 bored crypto 93152 23691 0 0 3 0x40014200 acpi0 acpi0 57055 188849 0 0 3 0x14200 bored softnet 55044 277093 0 0 3 0x14200 bored systqmp 83117 182699 0 0 3 0x14200 bored systq 29022 130006 0 0 3 0x40014200 bored softclock 13475 222512 0 0 3 0x40014200 idle0 1 327949 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 9502 6344K 6734K 78643K 11165 0 pcb 13 8K 8K 78643K 95 0 rtable 111 5K 7K 78643K 378 0 ifaddr 77 15K 15K 78643K 122 0 counters 21 16K 16K 78643K 25 0 ioctlops 0 0K 4K 78643K 88 0 iov 0 0K 32K 78643K 72 0 mount 1 1K 1K 78643K 1 0 vnodes 1215 76K 77K 78643K 1414 0 UFS quota 1 32K 32K 78643K 1 0 UFS mount 5 36K 36K 78643K 5 0 shm 2 1K 5K 78643K 4 0 VM map 2 0K 0K 78643K 2 0 sem 12 0K 1K 78643K 73 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1809 195K 288K 78643K 12938 0 file desc 4 9K 25K 78643K 407 0 sigio 0 0K 0K 78643K 12 0 proc 49 38K 55K 78643K 432 0 subproc 32 2K 2K 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 33 0 in_multi 56 3K 3K 78643K 100 0 ether_multi 1 0K 0K 78643K 15 0 mrt 0 0K 0K 78643K 7 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 241 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 133 72K 72K 78643K 1833 0 UVM aobj 14 3K 3K 78643K 19 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 ip6_options 0 0K 0K 78643K 81 0 NDP 12 0K 0K 78643K 22 0 temp 109 3042K 3106K 78643K 11124 0 kqueue 3 4K 12K 78643K 24 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 10 0 5 1 0 1 1 0 8 0 rtpcb 80 35 0 33 1 0 1 1 0 8 0 rtentry 112 70 0 28 2 0 2 2 0 8 0 unpcb 120 269 0 260 1 0 1 1 0 8 0 syncache 264 7 0 7 3 2 1 1 0 8 1 tcpqe 32 656 0 656 2 2 0 1 0 8 0 tcpcb 544 125 0 120 1 0 1 1 0 8 0 ipq 40 1 0 0 1 0 1 1 0 8 0 ipqe 40 2 0 1 1 0 1 1 0 8 0 inpcb 280 954 0 946 3 1 2 2 0 8 1 rttmr 72 2 0 2 1 1 0 1 0 8 0 nd6 48 9 0 3 1 0 1 1 0 8 0 pfstscr 40 1 0 0 1 0 1 1 0 8 0 pfrktable 1344 26 0 23 1 0 1 1 0 8 0 pftag 88 7 0 6 1 0 1 1 0 8 0 pfstitem 24 4 0 0 1 0 1 1 0 8 0 pfstkey 112 4 0 0 1 0 1 1 0 8 0 pfstate 328 2 0 0 1 0 1 1 0 8 0 pfrule 1360 22 0 8 2 0 2 2 0 8 0 art_heap8 4096 2 0 0 2 0 2 2 0 8 0 art_heap4 256 255 0 57 13 0 13 13 0 8 0 art_table 32 257 0 57 2 0 2 2 0 8 0 art_node 16 68 0 30 1 0 1 1 0 8 0 sysvmsgpl 40 14 0 6 1 0 1 1 0 8 0 semupl 112 2 0 2 1 1 0 1 0 8 0 semapl 112 69 0 59 1 0 1 1 0 8 0 shmpl 112 17 0 5 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 1941 0 546 88 0 88 88 0 8 0 ffsino 240 1941 0 546 83 0 83 83 0 8 0 nchpl 144 2634 0 1047 60 0 60 60 0 8 0 uvmvnodes 72 2113 0 0 39 0 39 39 0 8 0 vnodes 208 2113 0 0 112 0 112 112 0 8 0 namei 1024 7122 0 7122 2 1 1 1 0 8 1 vcpupl 1984 5 0 0 1 0 1 1 0 8 0 vmpool 528 13 0 8 1 0 1 1 0 8 0 pfiaddrpl 120 10 0 6 1 0 1 1 0 8 0 scxspl 192 7200 0 7200 1 0 1 1 0 8 1 plimitpl 152 57 0 50 1 0 1 1 0 8 0 sigapl 424 591 0 563 4 0 4 4 0 8 0 futexpl 56 7921 0 7921 2 1 1 1 0 8 1 knotepl 112 97 0 78 1 0 1 1 0 8 0 kqueuepl 144 46 0 44 1 0 1 1 0 8 0 pipelkpl 16 118 0 108 1 0 1 1 0 8 0 pipepl 120 236 0 217 1 0 1 1 0 8 0 fdescpl 432 576 0 563 2 0 2 2 0 8 0 filepl 120 3610 0 3515 4 0 4 4 0 8 1 lockfpl 104 67 0 66 1 0 1 1 0 8 0 lockfspl 48 22 0 21 1 0 1 1 0 8 0 sessionpl 112 18 0 8 1 0 1 1 0 8 0 pgrppl 48 18 0 8 1 0 1 1 0 8 0 ucredpl 96 419 0 412 1 0 1 1 0 8 0 zombiepl 144 563 0 563 1 0 1 1 0 8 1 processpl 920 591 0 563 4 0 4 4 0 8 0 procpl 624 1037 0 1003 5 1 4 4 0 8 1 sosppl 128 6 0 5 1 0 1 1 0 8 0 sockpl 400 1263 0 1244 5 1 4 4 0 8 0 mcl64k 65536 810 0 810 66 43 23 65 0 8 23 mcl16k 16384 1 0 1 1 1 0 1 0 8 0 mcl12k 12288 13 0 13 3 2 1 1 0 8 1 mcl9k 9216 14 0 14 2 1 1 1 0 8 1 mcl8k 8192 11 0 11 3 2 1 1 0 8 1 mcl4k 4096 52 0 52 3 2 1 1 0 8 1 mcl2k2 2112 1 0 1 1 1 0 1 0 8 0 mcl2k 2048 72699 0 72637 21 12 9 18 0 8 1 mtagpl 80 52 0 19 2 1 1 1 0 8 0 mbufpl 256 118927 0 118749 58 36 22 42 0 8 8 bufpl 280 3983 0 127 276 0 276 276 0 8 0 anonpl 16 82024 0 67725 88 9 79 80 0 107 16 amapchunkpl 152 3154 0 3025 19 12 7 19 0 158 1 amappl16 192 3450 0 2593 71 19 52 56 0 8 8 amappl15 184 188 0 186 1 0 1 1 0 8 0 amappl14 176 24 0 18 1 0 1 1 0 8 0 amappl13 168 73 0 69 1 0 1 1 0 8 0 amappl12 160 16 0 15 1 0 1 1 0 8 0 amappl11 152 179 0 170 1 0 1 1 0 8 0 amappl10 144 23 0 18 1 0 1 1 0 8 0 amappl9 136 341 0 339 1 0 1 1 0 8 0 amappl8 128 360 0 317 2 0 2 2 0 8 0 amappl7 120 114 0 100 1 0 1 1 0 8 0 amappl6 112 162 0 154 1 0 1 1 0 8 0 amappl5 104 570 0 561 1 0 1 1 0 8 0 amappl4 96 470 0 444 1 0 1 1 0 8 0 amappl3 88 127 0 121 1 0 1 1 0 8 0 amappl2 80 3906 0 3849 2 0 2 2 0 8 0 amappl1 72 19684 0 19286 22 13 9 17 0 8 0 amappl 80 1315 0 1271 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 5 1 0 1 1 0 8 0 uaddrrnd 24 589 0 571 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 589 0 571 1 0 1 1 0 8 0 vmmpekpl 168 7461 0 7434 2 0 2 2 0 8 0 vmmpepl 168 76238 0 74393 139 21 118 118 0 357 31 vmsppl 272 588 0 571 3 1 2 2 0 8 0 pdppl 4096 1184 0 1147 7 1 6 6 0 8 0 pvpl 32 225098 0 207905 197 11 186 190 0 265 34 pmappl 200 588 0 571 2 0 2 2 0 8 1 extentpl 40 53 0 36 1 0 1 1 0 8 0 phpool 112 368 0 103 10 0 10 10 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(ffffffff821cf907) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd806b46d500,26c,184,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff8000009f5760) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805dabe4b8,9,fffffd806b46d400,0,0,ffff80001d797eb0) at tcp_usrreq+0xa54 sosend(fffffd805dabe4b8,0,ffff80001d79e7c8,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d797eb0,4,ffff80001d79e7c8,0,ffff80001d79e8b0) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d797eb0,ffff80001d79e860,ffff80001d79e8b0) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d79e930) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffdeb90, 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(ffffffff821cf907) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd806b46d500,26c,184,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff8000009f5760) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805dabe4b8,9,fffffd806b46d400,0,0,ffff80001d797eb0) at tcp_usrreq+0xa54 sosend(fffffd805dabe4b8,0,ffff80001d79e7c8,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d797eb0,4,ffff80001d79e7c8,0,ffff80001d79e8b0) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d797eb0,ffff80001d79e860,ffff80001d79e8b0) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d79e930) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffdeb90, count: -10