panic: m_copym0: short mbuf chain Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *167373 13824 0 0x12 0 0 sshd db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff823b3292) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8058215d00,494,43c,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac0320) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da63008,9,fffffd8058215c00,0,0,ffff80001d717eb0) at tcp_usrreq+0xa54 sosend(fffffd805da63008,0,ffff80001d6cac68,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d717eb0,4,ffff80001d6cac68,0,ffff80001d6cad50) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d717eb0,ffff80001d6cad00,ffff80001d6cad50) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d6cadd0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffe6740, 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(ffffffff823b3292) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8058215d00,494,43c,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac0320) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da63008,9,fffffd8058215c00,0,0,ffff80001d717eb0) at tcp_usrreq+0xa54 sosend(fffffd805da63008,0,ffff80001d6cac68,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d717eb0,4,ffff80001d6cac68,0,ffff80001d6cad50) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d717eb0,ffff80001d6cad00,ffff80001d6cad50) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d6cadd0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffe6740, count: -10 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff80001d6ca730 rbx 0xffff80001d6ca7e0 rdx 0x2 rcx 0 rax 0x1 r8 0xffffffff81fccd5f kprintf+0x15f r9 0x1 r10 0x2 r11 0x8ed47223cf53de64 r12 0x3000000008 r13 0xffff80001d6ca740 r14 0x100 r15 0x1 rip 0xffffffff81b969e8 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff80001d6ca720 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (sshd) pid=167373 stat=onproc flags process=12 proc=0 pri=24, usrpri=50, nice=20 forw=0xffffffffffffffff, list=0xffff80001d718870,0xffff80001d717290 process=0xffff8000ffff8ae0 user=0xffff80001d6c5000, vmspace=0xfffffd806bc0a660 estcpu=0, cpticks=0, pctcpu=0.0 user=0, sys=0, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 16988 100305 66223 0 2 0 syz-executor.1 16988 30679 66223 0 2 0x4000000 syz-executor.1 84078 132247 0 0 3 0x14280 nfsidl nfsio 50687 357296 0 0 3 0x14280 nfsidl nfsio 82035 510969 0 0 3 0x14280 nfsidl nfsio 89889 66606 0 0 3 0x14280 nfsidl nfsio 6036 93519 0 0 3 0x14280 nfsidl nfsio 25622 339049 0 0 3 0x14280 nfsidl nfsio 56983 488964 0 0 3 0x14280 nfsidl nfsio 44757 222081 0 0 3 0x14280 nfsidl nfsio 95152 274704 0 0 3 0x14280 nfsidl nfsio 83616 181602 0 0 3 0x14280 nfsidl nfsio 73493 328211 0 0 3 0x14280 nfsidl nfsio 92530 6370 0 0 3 0x14280 nfsidl nfsio 62103 5350 0 0 3 0x14280 nfsidl nfsio 41934 404966 0 0 3 0x14280 nfsidl nfsio 80258 14719 0 0 3 0x14280 nfsidl nfsio 81092 122690 0 0 3 0x14280 nfsidl nfsio 24566 19931 0 0 3 0x14280 nfsidl nfsio 22021 283431 0 0 3 0x14280 nfsidl nfsio 51889 302254 0 0 3 0x14280 nfsidl nfsio 49901 256964 0 0 3 0x14280 nfsidl nfsio 75177 126668 0 0 3 0x14200 bored sosplice 69713 23770 95671 0 2 0x2 syz-executor.0 66223 185051 95671 0 3 0x82 nanosleep syz-executor.1 95671 316130 84003 0 2 0x2 syz-fuzzer 95671 57123 84003 0 3 0x4000082 nanosleep syz-fuzzer 95671 231835 84003 0 3 0x4000082 thrsleep syz-fuzzer 95671 55924 84003 0 3 0x4000082 thrsleep syz-fuzzer 95671 18989 84003 0 3 0x4000082 thrsleep syz-fuzzer 95671 48378 84003 0 3 0x4000082 thrsleep syz-fuzzer 95671 60855 84003 0 3 0x4000082 thrsleep syz-fuzzer 95671 65811 84003 0 3 0x4000082 thrsleep syz-fuzzer 84003 420570 13824 0 3 0x10008a pause ksh *13824 167373 67178 0 7 0x12 sshd 75483 187208 1 0 3 0x100083 ttyin getty 67178 303058 1 0 3 0x80 select sshd 6364 82336 30850 73 3 0x100090 kqread syslogd 30850 503026 1 0 3 0x100082 netio syslogd 83017 18407 1 77 3 0x100090 poll dhclient 38743 157615 1 0 3 0x80 poll dhclient 87640 222215 0 0 3 0x14200 bored smr 18598 423161 0 0 2 0x14200 zerothread 8123 61020 0 0 3 0x14200 aiodoned aiodoned 34393 234611 0 0 3 0x14200 syncer update 96826 268079 0 0 3 0x14200 cleaner cleaner 17831 220201 0 0 3 0x14200 reaper reaper 13897 321478 0 0 3 0x14200 pgdaemon pagedaemon 53255 406435 0 0 3 0x14200 bored crynlk 83737 341889 0 0 3 0x14200 bored crypto 79186 254547 0 0 3 0x40014200 acpi0 acpi0 58482 302415 0 0 3 0x14200 bored softnet 60360 468840 0 0 3 0x14200 bored systqmp 75332 192991 0 0 3 0x14200 bored systq 58267 485434 0 0 3 0x40014200 bored softclock 22081 297617 0 0 3 0x40014200 idle0 1 61880 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 9504 6351K 6605K 78643K 10997 0 pcb 13 8K 8K 78643K 130 0 rtable 102 3K 7K 78643K 290 0 ifaddr 63 12K 13K 78643K 110 0 counters 21 16K 16K 78643K 24 0 ioctlops 0 0K 4K 78643K 1284 0 iov 0 0K 12K 78643K 42 0 mount 1 1K 1K 78643K 1 0 vnodes 1219 77K 77K 78643K 1403 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 1K 1K 78643K 44 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1809 195K 288K 78643K 12938 0 file desc 5 13K 25K 78643K 573 0 proc 50 38K 63K 78643K 390 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 17 0 in_multi 29 1K 2K 78643K 54 0 ether_multi 1 0K 0K 78643K 7 0 mrt 0 0K 0K 78643K 8 0 ISOFS mount 1 32K 32K 78643K 1 0 MSDOSFS mount 1 16K 16K 78643K 1 0 ttys 79 360K 360K 78643K 79 0 exec 0 0K 1K 78643K 194 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 56K 56K 78643K 2168 0 UVM aobj 8 2K 2K 78643K 11 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 ip6_options 0 0K 0K 78643K 30 0 NDP 11 0K 0K 78643K 19 0 temp 94 3852K 3916K 78643K 9204 0 kqueue 3 4K 6K 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 27 0 25 1 0 1 1 0 8 0 rtentry 112 54 0 13 2 0 2 2 0 8 0 unpcb 120 93 0 85 1 0 1 1 0 8 0 syncache 264 6 0 6 2 2 0 1 0 8 0 sackhl 24 1 0 1 1 0 1 1 0 8 1 tcpqe 32 41 0 41 1 1 0 1 0 8 0 tcpcb 544 78 0 74 1 0 1 1 0 8 0 ipq 40 2 0 2 1 1 0 1 0 8 0 ipqe 40 90 0 90 1 1 0 1 0 8 0 inpcb 280 261 0 254 1 0 1 1 0 8 0 rttmr 72 4 0 4 2 1 1 1 0 8 1 nd6 48 8 0 4 1 0 1 1 0 8 0 ppxss 1128 1 0 1 1 1 0 1 0 8 0 pfosfp 40 1 0 0 1 0 1 1 0 8 0 pfosfpen 112 1 0 0 1 0 1 1 0 8 0 pfrktable 1344 22 0 22 2 2 0 1 0 8 0 pftag 88 6 0 4 1 0 1 1 0 8 0 pfrule 1360 95 0 7 8 0 8 8 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 215 0 42 13 0 13 13 0 8 0 art_table 32 216 0 42 2 0 2 2 0 8 0 art_node 16 53 0 15 1 0 1 1 0 8 0 semupl 112 2 0 2 1 1 0 1 0 8 0 semapl 112 38 0 28 1 0 1 1 0 8 0 shmpl 112 9 0 3 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 2098 0 700 88 0 88 88 0 8 0 ffsino 240 2098 0 700 83 0 83 83 0 8 0 nchpl 144 2956 0 1354 60 0 60 60 0 8 0 uvmvnodes 72 2223 0 0 41 0 41 41 0 8 0 vnodes 208 2223 0 0 117 0 117 117 0 8 0 namei 1024 9980 0 9980 5 4 1 1 0 8 1 vcpupl 1984 3 0 0 1 0 1 1 0 8 0 vmpool 528 5 0 2 1 0 1 1 0 8 0 pfiaddrpl 120 6 0 6 1 1 0 1 0 8 0 scxspl 192 8361 0 8361 1 0 1 1 0 8 1 plimitpl 152 22 0 15 1 0 1 1 0 8 0 sigapl 424 780 0 731 6 0 6 6 0 8 0 futexpl 56 8470 0 8470 5 4 1 1 0 8 1 knotepl 112 65 0 46 1 0 1 1 0 8 0 kqueuepl 144 18 0 16 1 0 1 1 0 8 0 pipelkpl 16 99 0 89 1 0 1 1 0 8 0 pipepl 120 198 0 179 1 0 1 1 0 8 0 fdescpl 432 745 0 731 2 0 2 2 0 8 0 filepl 120 5108 0 5013 4 0 4 4 0 8 1 lockfpl 104 1748 0 1747 1 0 1 1 0 8 0 lockfspl 48 559 0 558 1 0 1 1 0 8 0 sessionpl 112 17 0 7 1 0 1 1 0 8 0 pgrppl 48 17 0 7 1 0 1 1 0 8 0 ucredpl 96 1268 0 1261 1 0 1 1 0 8 0 zombiepl 144 731 0 731 1 0 1 1 0 8 1 processpl 920 780 0 731 7 0 7 7 0 8 0 procpl 624 1571 0 1514 7 2 5 5 0 8 0 sosppl 128 2 0 2 1 1 0 1 0 8 0 sockpl 400 386 0 369 7 4 3 3 0 8 1 mcl64k 65536 23 0 23 5 4 1 1 0 8 1 mcl16k 16384 3 0 3 3 3 0 1 0 8 0 mcl12k 12288 37 0 37 6 5 1 1 0 8 1 mcl9k 9216 6 0 6 4 3 1 1 0 8 1 mcl8k 8192 8 0 8 4 4 0 1 0 8 0 mcl4k 4096 30 0 30 7 6 1 1 0 8 1 mcl2k2 2112 3 0 3 2 1 1 1 0 8 1 mcl2k 2048 74849 0 74797 16 9 7 13 0 8 0 mtagpl 80 53 0 9 2 1 1 1 0 8 0 mbufpl 256 122111 0 121948 27 12 15 19 0 8 0 bufpl 280 3970 0 126 275 0 275 275 0 8 0 anonpl 16 69526 0 54027 68 2 66 66 0 107 0 amapchunkpl 152 2837 0 2707 8 2 6 8 0 158 0 amappl16 192 3245 0 2353 45 0 45 45 0 8 0 amappl15 184 1 0 0 1 0 1 1 0 8 0 amappl14 176 23 0 19 1 0 1 1 0 8 0 amappl13 168 26 0 23 1 0 1 1 0 8 0 amappl12 160 18 0 13 1 0 1 1 0 8 0 amappl11 152 344 0 333 1 0 1 1 0 8 0 amappl10 144 254 0 250 1 0 1 1 0 8 0 amappl9 136 365 0 363 1 0 1 1 0 8 0 amappl8 128 337 0 290 2 0 2 2 0 8 0 amappl7 120 350 0 337 1 0 1 1 0 8 0 amappl6 112 325 0 317 1 0 1 1 0 8 0 amappl5 104 703 0 692 1 0 1 1 0 8 0 amappl4 96 421 0 395 1 0 1 1 0 8 0 amappl3 88 142 0 137 1 0 1 1 0 8 0 amappl2 80 5122 0 5055 2 0 2 2 0 8 0 amappl1 72 22682 0 22273 23 14 9 17 0 8 0 amappl 80 1684 0 1642 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 10 0 3 1 0 1 1 0 8 0 uaddrrnd 24 750 0 733 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 750 0 733 1 0 1 1 0 8 0 vmmpekpl 168 8426 0 8398 2 0 2 2 0 8 0 vmmpepl 168 92511 0 90527 119 27 92 107 0 357 5 vmsppl 272 749 0 733 2 0 2 2 0 8 0 pdppl 4096 1506 0 1469 6 1 5 6 0 8 0 pvpl 32 219176 0 200616 164 8 156 160 0 265 0 pmappl 200 749 0 733 1 0 1 1 0 8 0 extentpl 40 53 0 36 1 0 1 1 0 8 0 phpool 112 288 0 51 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(ffffffff823b3292) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8058215d00,494,43c,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac0320) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da63008,9,fffffd8058215c00,0,0,ffff80001d717eb0) at tcp_usrreq+0xa54 sosend(fffffd805da63008,0,ffff80001d6cac68,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d717eb0,4,ffff80001d6cac68,0,ffff80001d6cad50) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d717eb0,ffff80001d6cad00,ffff80001d6cad50) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d6cadd0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffe6740, 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(ffffffff823b3292) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8058215d00,494,43c,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac0320) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da63008,9,fffffd8058215c00,0,0,ffff80001d717eb0) at tcp_usrreq+0xa54 sosend(fffffd805da63008,0,ffff80001d6cac68,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d717eb0,4,ffff80001d6cac68,0,ffff80001d6cad50) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d717eb0,ffff80001d6cad00,ffff80001d6cad50) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d6cadd0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffe6740, count: -10