panic: m_copym0: short mbuf chain Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *155648 64099 0 0x12 0 0 sshd db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff821cc032) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8066336b00,27c,1fc,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff8000009f5320) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805dac6968,9,fffffd8066336a00,0,0,ffff80001d7979d0) at tcp_usrreq+0xa54 sosend(fffffd805dac6968,0,ffff80001d79eac8,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d7979d0,4,ffff80001d79eac8,0,ffff80001d79ebb0) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d7979d0,ffff80001d79eb60,ffff80001d79ebb0) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d79ec30) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffee900, 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(ffffffff821cc032) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8066336b00,27c,1fc,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff8000009f5320) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805dac6968,9,fffffd8066336a00,0,0,ffff80001d7979d0) at tcp_usrreq+0xa54 sosend(fffffd805dac6968,0,ffff80001d79eac8,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d7979d0,4,ffff80001d79eac8,0,ffff80001d79ebb0) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d7979d0,ffff80001d79eb60,ffff80001d79ebb0) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d79ec30) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffee900, count: -10 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff80001d79e590 rbx 0xffff80001d79e640 rdx 0x2 rcx 0 rax 0x1 r8 0xffffffff8185100f kprintf+0x15f r9 0x1 r10 0x2 r11 0xf4445f3f513459a9 r12 0x3000000008 r13 0xffff80001d79e5a0 r14 0x100 r15 0x1 rip 0xffffffff81666fb8 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff80001d79e580 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (sshd) pid=155648 stat=onproc flags process=12 proc=0 pri=24, usrpri=50, nice=20 forw=0xffffffffffffffff, list=0xffff80001d798ae0,0xffff80001d797020 process=0xffff8000ffff8018 user=0xffff80001d799000, vmspace=0xfffffd806bc09bb0 estcpu=0, cpticks=0, pctcpu=0.0 user=0, sys=0, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 15919 12236 97086 0 2 0 syz-executor.1 15919 30215 97086 0 2 0x4000000 syz-executor.1 97086 329802 69994 0 3 0x82 nanosleep syz-executor.1 73187 337538 0 0 3 0x14280 nfsidl nfsio 26196 145168 0 0 3 0x14280 nfsidl nfsio 10682 463619 0 0 3 0x14280 nfsidl nfsio 19606 252397 0 0 3 0x14280 nfsidl nfsio 9309 159162 0 0 3 0x14280 nfsidl nfsio 6650 436219 0 0 3 0x14280 nfsidl nfsio 72638 235253 0 0 3 0x14280 nfsidl nfsio 35973 172290 0 0 3 0x14280 nfsidl nfsio 10642 371904 0 0 3 0x14280 nfsidl nfsio 24842 384637 0 0 3 0x14280 nfsidl nfsio 22569 212012 0 0 3 0x14280 nfsidl nfsio 47038 272873 0 0 3 0x14280 nfsidl nfsio 43622 247404 0 0 3 0x14280 nfsidl nfsio 58423 180641 0 0 3 0x14280 nfsidl nfsio 25332 514728 0 0 3 0x14280 nfsidl nfsio 96360 456606 0 0 3 0x14280 nfsidl nfsio 63479 312588 0 0 3 0x14280 nfsidl nfsio 69117 13496 0 0 3 0x14280 nfsidl nfsio 81642 5674 0 0 3 0x14280 nfsidl nfsio 17743 449207 0 0 3 0x14280 nfsidl nfsio 88277 433328 69994 0 2 0x2 syz-executor.0 69994 343473 70220 0 3 0x82 thrsleep syz-fuzzer 69994 93471 70220 0 2 0x4000482 syz-fuzzer 69994 477491 70220 0 2 0x4000002 syz-fuzzer 69994 107405 70220 0 3 0x4000082 thrsleep syz-fuzzer 69994 408348 70220 0 3 0x4000082 thrsleep syz-fuzzer 69994 20361 70220 0 3 0x4000082 thrsleep syz-fuzzer 69994 118968 70220 0 3 0x4000082 thrsleep syz-fuzzer 69994 285782 70220 0 3 0x4000082 thrsleep syz-fuzzer 70220 385510 64099 0 3 0x10008a pause ksh *64099 155648 72397 0 7 0x12 sshd 81593 221321 1 0 3 0x100083 ttyin getty 72397 286951 1 0 3 0x80 select sshd 28996 493027 93931 73 3 0x100090 kqread syslogd 93931 292971 1 0 3 0x100082 netio syslogd 78154 198632 1 77 3 0x100090 poll dhclient 52903 360150 1 0 3 0x80 poll dhclient 49297 28119 0 0 3 0x14200 bored smr 54007 470346 0 0 2 0x14200 zerothread 68955 428969 0 0 3 0x14200 aiodoned aiodoned 92909 364471 0 0 3 0x14200 syncer update 92870 445427 0 0 3 0x14200 cleaner cleaner 22641 154720 0 0 3 0x14200 reaper reaper 69539 513821 0 0 3 0x14200 pgdaemon pagedaemon 58183 252245 0 0 3 0x14200 bored crynlk 35544 308151 0 0 3 0x14200 bored crypto 38947 113125 0 0 3 0x40014200 acpi0 acpi0 83285 412728 0 0 3 0x14200 bored softnet 71508 246395 0 0 3 0x14200 bored systqmp 1478 42265 0 0 3 0x14200 bored systq 24698 371612 0 0 3 0x40014200 bored softclock 52427 41707 0 0 3 0x40014200 idle0 1 391364 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 9508 6346K 6736K 78643K 11412 0 pcb 13 8K 8K 78643K 69 0 rtable 105 4K 7K 78643K 369 0 ifaddr 78 15K 15K 78643K 141 0 counters 21 16K 16K 78643K 29 0 ioctlops 0 0K 4K 78643K 49 0 iov 0 0K 14K 78643K 400 0 mount 1 1K 1K 78643K 1 0 vnodes 1216 76K 77K 78643K 1655 0 UFS quota 1 32K 32K 78643K 1 0 UFS mount 5 36K 36K 78643K 5 0 shm 2 1K 5K 78643K 13 0 VM map 2 0K 0K 78643K 2 0 sem 12 0K 0K 78643K 438 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1809 195K 288K 78643K 12938 0 file desc 5 13K 25K 78643K 621 0 sigio 0 0K 0K 78643K 4 0 proc 50 38K 63K 78643K 423 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 14 0 in_multi 49 2K 3K 78643K 83 0 ether_multi 1 0K 0K 78643K 7 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 212 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 138 88K 90K 78643K 2309 0 UVM aobj 130 8K 8K 78643K 130 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 ip6_options 0 0K 0K 78643K 39 0 NDP 14 0K 0K 78643K 28 0 temp 114 3039K 3103K 78643K 22441 0 kqueue 3 4K 9K 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 35 0 33 1 0 1 1 0 8 0 rtentry 112 61 0 20 2 0 2 2 0 8 0 unpcb 120 143 0 135 1 0 1 1 0 8 0 syncache 264 5 0 5 2 2 0 1 0 8 0 tcpqe 32 61 0 61 2 2 0 1 0 8 0 tcpcb 544 117 0 111 1 0 1 1 0 8 0 inpcb 280 352 0 343 3 1 2 2 0 8 1 rttmr 72 1 0 1 1 1 0 1 0 8 0 ip6q 72 3 0 3 2 2 0 1 0 8 0 ip6af 40 9 0 9 2 2 0 1 0 8 0 nd6 48 10 0 6 1 0 1 1 0 8 0 pkpcb 40 2 0 2 1 1 0 1 0 8 0 ppxss 1128 3 0 3 3 3 0 1 0 8 0 pfstscr 40 4 0 2 1 0 1 1 0 8 0 pfrktable 1344 20 0 20 1 1 0 1 0 8 0 pftag 88 4 0 4 1 1 0 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 8 0 4 1 0 1 1 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 263 0 87 13 0 13 13 0 8 0 art_table 32 264 0 87 2 0 2 2 0 8 0 art_node 16 60 0 22 1 0 1 1 0 8 0 sysvmsgpl 40 22 0 8 1 0 1 1 0 8 0 semapl 112 436 0 426 1 0 1 1 0 8 0 shmpl 112 128 0 0 4 0 4 4 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 2653 0 1259 88 0 88 88 0 8 0 ffsino 240 2653 0 1259 83 0 83 83 0 8 0 nchpl 144 3909 0 2332 60 0 60 60 0 8 0 uvmvnodes 72 2824 0 0 52 0 52 52 0 8 0 vnodes 208 2824 0 0 149 0 149 149 0 8 0 namei 1024 10128 0 10128 1 0 1 1 0 8 1 vcpupl 1984 7 0 0 1 0 1 1 0 8 0 vmpool 528 7 0 0 1 0 1 1 0 8 0 pfiaddrpl 120 6 0 6 1 1 0 1 0 8 0 scxspl 192 10615 0 10615 1 0 1 1 0 8 1 plimitpl 152 36 0 29 1 0 1 1 0 8 0 sigapl 424 824 0 776 6 0 6 6 0 8 0 futexpl 56 14257 0 14257 1 0 1 1 0 8 1 knotepl 112 97 0 78 1 0 1 1 0 8 0 kqueuepl 144 47 0 45 1 0 1 1 0 8 0 pipelkpl 16 116 0 106 1 0 1 1 0 8 0 pipepl 120 232 0 213 1 0 1 1 0 8 0 fdescpl 432 790 0 776 2 0 2 2 0 8 0 filepl 120 3938 0 3843 4 0 4 4 0 8 0 lockfpl 104 122 0 121 1 0 1 1 0 8 0 lockfspl 48 45 0 44 1 0 1 1 0 8 0 sessionpl 112 18 0 8 1 0 1 1 0 8 0 pgrppl 48 36 0 26 1 0 1 1 0 8 0 ucredpl 96 302 0 295 1 0 1 1 0 8 0 zombiepl 144 776 0 776 1 0 1 1 0 8 1 processpl 920 824 0 776 7 0 7 7 0 8 0 procpl 624 1554 0 1498 6 1 5 5 0 8 0 sockpl 400 532 0 513 4 1 3 4 0 8 1 mcl64k 65536 32 0 32 3 2 1 1 0 8 1 mcl16k 16384 2 0 2 1 0 1 1 0 8 1 mcl12k 12288 16 0 16 2 1 1 1 0 8 1 mcl9k 9216 8 0 8 4 3 1 1 0 8 1 mcl8k 8192 8 0 8 4 3 1 1 0 8 1 mcl4k 4096 35 0 35 3 2 1 1 0 8 1 mcl2k2 2112 1 0 1 1 1 0 1 0 8 0 mcl2k 2048 73742 0 73702 15 9 6 13 0 8 0 mtagpl 80 42 0 10 2 1 1 1 0 8 0 mbufpl 256 119343 0 119137 18 4 14 14 0 8 0 bufpl 280 4608 0 134 320 0 320 320 0 8 0 anonpl 16 86581 0 71821 88 15 73 74 0 107 8 amapchunkpl 152 4716 0 4579 28 5 23 27 0 158 15 amappl16 192 3958 0 3107 64 14 50 55 0 8 7 amappl15 184 1 0 0 1 0 1 1 0 8 0 amappl14 176 244 0 237 1 0 1 1 0 8 0 amappl13 168 41 0 37 1 0 1 1 0 8 0 amappl12 160 10 0 8 1 0 1 1 0 8 0 amappl11 152 49 0 40 1 0 1 1 0 8 0 amappl10 144 372 0 366 1 0 1 1 0 8 0 amappl9 136 381 0 379 1 0 1 1 0 8 0 amappl8 128 366 0 319 2 0 2 2 0 8 0 amappl7 120 186 0 173 1 0 1 1 0 8 0 amappl6 112 33 0 23 1 0 1 1 0 8 0 amappl5 104 727 0 716 1 0 1 1 0 8 0 amappl4 96 438 0 412 1 0 1 1 0 8 0 amappl3 88 342 0 336 1 0 1 1 0 8 0 amappl2 80 5434 0 5365 2 0 2 2 0 8 0 amappl1 72 24300 0 23887 23 14 9 17 0 8 0 amappl 80 1787 0 1741 3 1 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 64 129 0 0 3 0 3 3 0 8 0 uaddrrnd 24 797 0 776 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 797 0 776 1 0 1 1 0 8 0 vmmpekpl 168 8656 0 8624 2 0 2 2 0 8 0 vmmpepl 168 100390 0 98431 164 48 116 140 0 357 26 vmsppl 272 796 0 776 2 0 2 2 0 8 0 pdppl 4096 1600 0 1559 8 2 6 6 0 8 0 pvpl 32 260846 0 243000 212 31 181 182 0 265 29 pmappl 200 796 0 776 2 0 2 2 0 8 0 extentpl 40 53 0 36 1 0 1 1 0 8 0 phpool 112 257 0 26 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(ffffffff821cc032) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8066336b00,27c,1fc,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff8000009f5320) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805dac6968,9,fffffd8066336a00,0,0,ffff80001d7979d0) at tcp_usrreq+0xa54 sosend(fffffd805dac6968,0,ffff80001d79eac8,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d7979d0,4,ffff80001d79eac8,0,ffff80001d79ebb0) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d7979d0,ffff80001d79eb60,ffff80001d79ebb0) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d79ec30) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffee900, 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(ffffffff821cc032) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8066336b00,27c,1fc,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff8000009f5320) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805dac6968,9,fffffd8066336a00,0,0,ffff80001d7979d0) at tcp_usrreq+0xa54 sosend(fffffd805dac6968,0,ffff80001d79eac8,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d7979d0,4,ffff80001d79eac8,0,ffff80001d79ebb0) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d7979d0,ffff80001d79eb60,ffff80001d79ebb0) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d79ec30) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffee900, count: -10