panic: m_copym0: short mbuf chain Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND * 23547 28412 0 0x12 0 0 sshd db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff821cb941) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd805e10c500,29c,1f4,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff8000009f4440) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805dad27d8,9,fffffd805e10c400,0,0,ffff80001d798120) at tcp_usrreq+0xa54 sosend(fffffd805dad27d8,0,ffff80001d768778,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d798120,4,ffff80001d768778,0,ffff80001d768860) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d798120,ffff80001d768810,ffff80001d768860) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d7688e0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffeae90, 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(ffffffff821cb941) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd805e10c500,29c,1f4,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff8000009f4440) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805dad27d8,9,fffffd805e10c400,0,0,ffff80001d798120) at tcp_usrreq+0xa54 sosend(fffffd805dad27d8,0,ffff80001d768778,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d798120,4,ffff80001d768778,0,ffff80001d768860) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d798120,ffff80001d768810,ffff80001d768860) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d7688e0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffeae90, count: -10 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff80001d768240 rbx 0xffff80001d7682f0 rdx 0x2 rcx 0 rax 0x1 r8 0xffffffff8182317f kprintf+0x15f r9 0x1 r10 0x2 r11 0x4bbefbe8cdd0a9c4 r12 0x3000000008 r13 0xffff80001d768250 r14 0x100 r15 0x1 rip 0xffffffff8186b358 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff80001d768230 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (sshd) pid=23547 stat=onproc flags process=12 proc=0 pri=24, usrpri=50, nice=20 forw=0xffffffffffffffff, list=0xffff80001d798ae0,0xffff80001d797500 process=0xffff8000ffff9210 user=0xffff80001d763000, vmspace=0xfffffd806bc0a770 estcpu=0, cpticks=0, pctcpu=0.1 user=0, sys=0, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 42913 76278 49639 0 2 0 syz-executor.1 42913 309855 49639 0 2 0x4000000 syz-executor.1 73141 404338 93289 0 2 0x2 syz-executor.0 49639 110155 93289 0 3 0x82 nanosleep syz-executor.1 93289 267141 16078 0 2 0x2 syz-fuzzer 93289 380906 16078 0 2 0x4000002 syz-fuzzer 93289 184910 16078 0 3 0x4000082 thrsleep syz-fuzzer 93289 221220 16078 0 3 0x4000082 thrsleep syz-fuzzer 93289 1873 16078 0 3 0x4000082 thrsleep syz-fuzzer 93289 97281 16078 0 3 0x4000082 thrsleep syz-fuzzer 93289 332135 16078 0 3 0x4000082 thrsleep syz-fuzzer 16078 233795 28412 0 3 0x10008a pause ksh *28412 23547 82633 0 7 0x12 sshd 87753 294651 1 0 3 0x100083 ttyin getty 82633 18279 1 0 3 0x80 select sshd 45988 347240 6178 73 3 0x100090 kqread syslogd 6178 251065 1 0 3 0x100082 netio syslogd 56928 400747 1 77 3 0x100090 poll dhclient 34679 263447 1 0 3 0x80 poll dhclient 57501 16862 0 0 3 0x14200 bored smr 67276 7054 0 0 2 0x14200 zerothread 9448 215667 0 0 3 0x14200 aiodoned aiodoned 41254 430183 0 0 3 0x14200 syncer update 52791 450599 0 0 3 0x14200 cleaner cleaner 42137 312375 0 0 3 0x14200 reaper reaper 86898 344065 0 0 3 0x14200 pgdaemon pagedaemon 58350 297623 0 0 3 0x14200 bored crynlk 27594 439906 0 0 3 0x14200 bored crypto 50825 426865 0 0 3 0x40014200 acpi0 acpi0 84114 322560 0 0 3 0x14200 bored softnet 65684 458602 0 0 3 0x14200 bored systqmp 99024 350538 0 0 3 0x14200 bored systq 49165 452060 0 0 3 0x40014200 bored softclock 5919 507877 0 0 3 0x40014200 idle0 1 383147 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 9480 6335K 7304K 78643K 10997 0 pcb 13 8K 8K 78643K 39 0 rtable 115 5K 6K 78643K 261 0 ifaddr 59 12K 12K 78643K 84 0 counters 21 16K 17K 78643K 25 0 ioctlops 0 0K 4K 78643K 31 0 iov 0 0K 12K 78643K 12 0 mount 1 1K 1K 78643K 1 0 vnodes 1221 77K 77K 78643K 1330 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 18 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1809 195K 288K 78643K 12938 0 file desc 5 13K 25K 78643K 126 0 sigio 0 0K 0K 78643K 4 0 proc 49 38K 54K 78643K 362 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 12 0 in_multi 33 2K 2K 78643K 43 0 ether_multi 1 0K 0K 78643K 5 0 ISOFS mount 1 32K 32K 78643K 1 0 MSDOSFS mount 1 16K 16K 78643K 1 0 ttys 37 175K 175K 78643K 37 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 118 22K 23K 78643K 1137 0 UVM aobj 2 2K 2K 78643K 2 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 ip6_options 0 0K 0K 78643K 21 0 NDP 9 0K 0K 78643K 17 0 temp 80 3030K 3094K 78643K 2091 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 6 0 0 1 0 1 1 0 8 0 rtpcb 80 29 0 27 1 0 1 1 0 8 0 rtentry 112 45 0 1 2 0 2 2 0 8 0 unpcb 120 63 0 55 1 0 1 1 0 8 0 syncache 264 6 0 6 2 1 1 1 0 8 1 tcpqe 32 22 0 22 1 0 1 1 0 8 1 tcpcb 544 68 0 64 1 0 1 1 0 8 0 ipq 40 2 0 2 1 0 1 1 0 8 1 ipqe 40 90 0 90 1 0 1 1 0 8 1 inpcb 280 162 0 155 1 0 1 1 0 8 0 nd6 48 6 0 0 1 0 1 1 0 8 0 pfrktable 1344 11 0 8 1 0 1 1 0 8 0 pftag 88 4 0 2 1 0 1 1 0 8 0 pfrule 1360 4 0 2 1 0 1 1 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 189 0 0 12 0 12 12 0 8 0 art_table 32 190 0 0 2 0 2 2 0 8 0 art_node 16 44 0 4 1 0 1 1 0 8 0 semupl 112 2 0 2 1 0 1 1 0 8 1 semapl 112 16 0 6 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 1558 0 162 88 0 88 88 0 8 0 ffsino 240 1558 0 162 83 0 83 83 0 8 0 nchpl 144 1902 0 300 60 0 60 60 0 8 0 uvmvnodes 72 1687 0 0 31 0 31 31 0 8 0 vnodes 208 1687 0 0 89 0 89 89 0 8 0 namei 1024 4837 0 4837 1 0 1 1 0 8 1 pfiaddrpl 120 4 0 2 1 0 1 1 0 8 0 scxspl 192 4856 0 4856 1 0 1 1 0 8 1 plimitpl 152 18 0 11 1 0 1 1 0 8 0 sigapl 424 312 0 284 4 0 4 4 0 8 0 futexpl 56 2024 0 2024 1 0 1 1 0 8 1 knotepl 112 65 0 46 1 0 1 1 0 8 0 kqueuepl 144 24 0 22 1 0 1 1 0 8 0 pipelkpl 16 82 0 72 1 0 1 1 0 8 0 pipepl 120 164 0 145 1 0 1 1 0 8 0 fdescpl 432 298 0 284 2 0 2 2 0 8 0 filepl 120 1630 0 1535 4 0 4 4 0 8 1 lockfpl 104 25 0 24 1 0 1 1 0 8 0 lockfspl 48 11 0 10 1 0 1 1 0 8 0 sessionpl 112 17 0 7 1 0 1 1 0 8 0 pgrppl 48 21 0 11 1 0 1 1 0 8 0 ucredpl 96 151 0 144 1 0 1 1 0 8 0 zombiepl 144 284 0 284 1 0 1 1 0 8 1 processpl 920 312 0 284 4 0 4 4 0 8 0 procpl 624 423 0 388 4 0 4 4 0 8 1 sockpl 400 254 0 237 3 0 3 3 0 8 1 mcl64k 65536 10 0 10 1 0 1 1 0 8 1 mcl12k 12288 1 0 1 1 0 1 1 0 8 1 mcl9k 9216 1 0 1 1 0 1 1 0 8 1 mcl8k 8192 1 0 1 1 0 1 1 0 8 1 mcl4k 4096 15 0 15 1 0 1 1 0 8 1 mcl2k 2048 75102 0 75054 13 1 12 12 0 8 5 mtagpl 80 66 0 5 3 1 2 2 0 8 0 mbufpl 256 119575 0 119387 22 1 21 21 0 8 9 bufpl 280 3458 0 126 238 0 238 238 0 8 0 anonpl 16 45165 0 30169 66 1 65 65 0 107 4 amapchunkpl 152 1434 0 1304 11 0 11 11 0 158 4 amappl16 192 1365 0 546 42 0 42 42 0 8 0 amappl15 184 54 0 50 1 0 1 1 0 8 0 amappl14 176 26 0 21 1 0 1 1 0 8 0 amappl13 168 26 0 23 1 0 1 1 0 8 0 amappl12 160 5 0 5 2 2 0 1 0 8 0 amappl11 152 88 0 77 1 0 1 1 0 8 0 amappl10 144 15 0 10 1 0 1 1 0 8 0 amappl9 136 413 0 411 1 0 1 1 0 8 0 amappl8 128 384 0 339 2 0 2 2 0 8 0 amappl7 120 107 0 94 1 0 1 1 0 8 0 amappl6 112 72 0 63 1 0 1 1 0 8 0 amappl5 104 204 0 195 1 0 1 1 0 8 0 amappl4 96 462 0 436 1 0 1 1 0 8 0 amappl3 88 102 0 95 1 0 1 1 0 8 0 amappl2 80 1557 0 1490 2 0 2 2 0 8 0 amappl1 72 14962 0 14546 24 9 15 17 0 8 6 amappl 80 665 0 625 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 1 0 0 1 0 1 1 0 8 0 uaddrrnd 24 298 0 284 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 298 0 284 1 0 1 1 0 8 0 vmmpekpl 168 6058 0 6034 2 0 2 2 0 8 0 vmmpepl 168 42564 0 40657 147 8 139 139 0 357 55 vmsppl 272 297 0 284 2 0 2 2 0 8 1 pdppl 4096 602 0 568 6 0 6 6 0 8 1 pvpl 32 146897 0 128959 158 0 158 158 0 265 11 pmappl 200 297 0 284 1 0 1 1 0 8 0 extentpl 40 53 0 36 1 0 1 1 0 8 0 phpool 112 245 0 4 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(ffffffff821cb941) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd805e10c500,29c,1f4,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff8000009f4440) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805dad27d8,9,fffffd805e10c400,0,0,ffff80001d798120) at tcp_usrreq+0xa54 sosend(fffffd805dad27d8,0,ffff80001d768778,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d798120,4,ffff80001d768778,0,ffff80001d768860) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d798120,ffff80001d768810,ffff80001d768860) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d7688e0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffeae90, 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(ffffffff821cb941) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd805e10c500,29c,1f4,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff8000009f4440) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805dad27d8,9,fffffd805e10c400,0,0,ffff80001d798120) at tcp_usrreq+0xa54 sosend(fffffd805dad27d8,0,ffff80001d768778,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d798120,4,ffff80001d768778,0,ffff80001d768860) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d798120,ffff80001d768810,ffff80001d768860) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d7688e0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffeae90, count: -10