panic: m_copym0: short mbuf chain Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *413184 67278 0 0x12 0 0 sshd db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff823b30a4) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8053524600,34c,304,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac0100) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da70008,9,fffffd8053524500,0,0,ffff80001d718600) at tcp_usrreq+0xa54 sosend(fffffd805da70008,0,ffff80001d6caac8,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d718600,4,ffff80001d6caac8,0,ffff80001d6cabb0) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d718600,ffff80001d6cab60,ffff80001d6cabb0) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d6cac30) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffe67a0, 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(ffffffff823b30a4) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8053524600,34c,304,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac0100) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da70008,9,fffffd8053524500,0,0,ffff80001d718600) at tcp_usrreq+0xa54 sosend(fffffd805da70008,0,ffff80001d6caac8,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d718600,4,ffff80001d6caac8,0,ffff80001d6cabb0) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d718600,ffff80001d6cab60,ffff80001d6cabb0) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d6cac30) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffe67a0, count: -10 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff80001d6ca590 rbx 0xffff80001d6ca640 rdx 0x2 rcx 0 rax 0x1 r8 0xffffffff81203d6f kprintf+0x15f r9 0x1 r10 0x2 r11 0xf1d1c5d199d0c397 r12 0x3000000008 r13 0xffff80001d6ca5a0 r14 0x100 r15 0x1 rip 0xffffffff81869548 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff80001d6ca580 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (sshd) pid=413184 stat=onproc flags process=12 proc=0 pri=24, usrpri=50, nice=20 forw=0xffffffffffffffff, list=0xffff80001d718ae0,0xffff80001d718130 process=0xffff8000ffff95a8 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 10040 80429 62974 0 2 0 syz-executor.0 10040 214891 62974 0 2 0x4000000 syz-executor.0 33908 42491 0 0 3 0x14200 acct acct 51884 409443 33456 0 2 0x2 syz-executor.1 14640 127994 0 0 3 0x14200 bored sosplice 62974 274295 33456 0 3 0x82 nanosleep syz-executor.0 33456 517823 16470 0 3 0x82 thrsleep syz-fuzzer 33456 333703 16470 0 3 0x4000082 nanosleep syz-fuzzer 33456 80792 16470 0 3 0x4000082 thrsleep syz-fuzzer 33456 429291 16470 0 3 0x4000082 thrsleep syz-fuzzer 33456 466936 16470 0 2 0x4000002 syz-fuzzer 33456 371155 16470 0 3 0x4000082 thrsleep syz-fuzzer 33456 263042 16470 0 3 0x4000082 thrsleep syz-fuzzer 33456 189948 16470 0 3 0x4000082 thrsleep syz-fuzzer 16470 32516 67278 0 3 0x10008a pause ksh *67278 413184 34026 0 7 0x12 sshd 5017 353043 1 0 3 0x100083 ttyin getty 34026 403863 1 0 3 0x80 select sshd 35584 84135 47598 73 3 0x100090 kqread syslogd 47598 511021 1 0 3 0x100082 netio syslogd 23883 62677 1 77 3 0x100090 poll dhclient 80625 385363 1 0 3 0x80 poll dhclient 27276 431255 0 0 3 0x14200 bored smr 33681 505850 0 0 2 0x14200 zerothread 77534 195126 0 0 3 0x14200 aiodoned aiodoned 8026 523987 0 0 3 0x14200 syncer update 78937 84871 0 0 3 0x14200 cleaner cleaner 30633 459846 0 0 3 0x14200 reaper reaper 16494 93098 0 0 3 0x14200 pgdaemon pagedaemon 60060 332940 0 0 3 0x14200 bored crynlk 52308 444159 0 0 3 0x14200 bored crypto 1025 163824 0 0 3 0x40014200 acpi0 acpi0 45740 124461 0 0 3 0x14200 bored softnet 21998 177591 0 0 3 0x14200 bored systqmp 83606 417618 0 0 3 0x14200 bored systq 95343 87263 0 0 3 0x40014200 bored softclock 64961 191876 0 0 3 0x40014200 idle0 1 371437 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 9509 6409K 7642K 78643K 14634 0 pcb 13 8K 8K 78643K 123 0 rtable 126 16K 16K 78643K 710 0 ifaddr 86 17K 19K 78643K 252 0 sysctl 2 0K 0K 78643K 2 0 counters 21 16K 17K 78643K 40 0 ioctlops 0 0K 4K 78643K 93 0 iov 0 0K 32K 78643K 92 0 mount 1 1K 1K 78643K 1 0 vnodes 1225 77K 77K 78643K 2237 0 UFS quota 1 32K 32K 78643K 1 0 UFS mount 5 36K 36K 78643K 5 0 shm 2 1K 5K 78643K 3 0 VM map 2 0K 0K 78643K 2 0 sem 12 0K 1K 78643K 160 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1809 195K 288K 78643K 12938 0 file desc 5 13K 25K 78643K 717 0 sigio 0 0K 0K 78643K 4 0 proc 50 38K 54K 78643K 462 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 45 0 in_multi 82 4K 4K 78643K 163 0 ether_multi 1 0K 0K 78643K 22 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 232 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 143 104K 113K 78643K 2529 0 UVM aobj 24 2K 2K 78643K 26 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 ip6_options 0 0K 0K 78643K 92 0 NDP 13 0K 0K 78643K 40 0 temp 108 3846K 3915K 78643K 15987 0 kqueue 3 4K 22K 78643K 39 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 9 0 3 1 0 1 1 0 8 0 rtpcb 80 68 0 66 1 0 1 1 0 8 0 rtentry 112 73 0 31 2 0 2 2 0 8 0 unpcb 120 207 0 199 1 0 1 1 0 8 0 syncache 264 11 0 11 5 4 1 1 0 8 1 sackhl 24 1 0 1 1 1 0 1 0 8 0 tcpqe 32 77 0 77 2 2 0 1 0 8 0 tcpcb 544 232 0 228 1 0 1 1 0 8 0 ipq 40 3 0 3 3 2 1 1 0 8 1 ipqe 40 92 0 92 3 2 1 1 0 8 1 inpcb 280 592 0 585 5 4 1 2 0 8 0 nd6 48 13 0 9 1 0 1 1 0 8 0 pfrktable 1344 142 0 133 3 2 1 2 0 8 0 pftag 88 13 0 8 1 0 1 1 0 8 0 pfrule 1360 36 0 26 1 0 1 1 0 8 0 art_heap8 4096 2 0 0 2 0 2 2 0 8 0 art_heap4 256 336 0 149 15 1 14 14 0 8 0 art_table 32 338 0 149 2 0 2 2 0 8 0 art_node 16 72 0 33 1 0 1 1 0 8 0 sysvmsgpl 40 8 0 3 1 0 1 1 0 8 0 semapl 112 153 0 143 1 0 1 1 0 8 0 shmpl 112 24 0 2 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 2334 0 931 88 0 88 88 0 8 0 ffsino 240 2334 0 931 83 0 83 83 0 8 0 nchpl 144 3778 0 2190 60 0 60 60 0 8 0 uvmvnodes 72 3294 0 0 60 0 60 60 0 8 0 vnodes 208 3294 0 0 174 0 174 174 0 8 0 namei 1024 11037 0 11037 3 2 1 1 0 8 1 vcpupl 1984 11 0 0 2 0 2 2 0 8 0 vmpool 528 15 0 4 1 0 1 1 0 8 0 pfiaddrpl 120 46 0 40 1 0 1 1 0 8 0 scxspl 192 9966 0 9966 2 1 1 1 0 8 1 plimitpl 152 66 0 59 1 0 1 1 0 8 0 sigapl 424 902 0 872 4 0 4 4 0 8 0 futexpl 56 14462 0 14462 3 2 1 1 0 8 1 knotepl 112 160 0 141 2 0 2 2 0 8 1 kqueuepl 144 102 0 98 1 0 1 1 0 8 0 pipepl 272 168 0 158 1 0 1 1 0 8 0 fdescpl 432 886 0 872 2 0 2 2 0 8 0 filepl 120 5514 0 5419 5 1 4 4 0 8 1 lockfpl 104 112 0 111 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 22 0 12 1 0 1 1 0 8 0 ucredpl 96 519 0 512 1 0 1 1 0 8 0 zombiepl 144 872 0 872 2 1 1 1 0 8 1 processpl 920 902 0 872 4 0 4 4 0 8 0 procpl 624 1729 0 1691 5 1 4 4 0 8 0 sosppl 128 10 0 10 5 4 1 1 0 8 1 sockpl 400 867 0 850 7 4 3 4 0 8 1 mcl64k 65536 314 0 314 36 35 1 33 0 8 1 mcl16k 16384 5 0 5 3 2 1 1 0 8 1 mcl12k 12288 17 0 17 5 4 1 1 0 8 1 mcl9k 9216 8 0 8 4 3 1 1 0 8 1 mcl8k 8192 32 0 32 6 5 1 1 0 8 1 mcl4k 4096 67 0 67 5 4 1 1 0 8 1 mcl2k2 2112 6 0 6 5 5 0 1 0 8 0 mcl2k 2048 75333 0 75267 19 10 9 14 0 8 0 mtagpl 80 591 0 189 10 1 9 9 0 8 0 mbufpl 256 125074 0 124105 91 26 65 67 0 8 4 bufpl 280 4441 0 126 309 0 309 309 0 8 0 anonpl 16 102735 0 86882 115 34 81 83 0 107 14 amapchunkpl 152 4192 0 4064 27 20 7 19 0 158 1 amappl16 192 5121 0 4197 83 30 53 59 0 8 6 amappl15 184 10 0 9 1 0 1 1 0 8 0 amappl14 176 22 0 18 1 0 1 1 0 8 0 amappl13 168 278 0 273 1 0 1 1 0 8 0 amappl12 160 16 0 13 1 0 1 1 0 8 0 amappl11 152 46 0 37 1 0 1 1 0 8 0 amappl10 144 17 0 14 1 0 1 1 0 8 0 amappl9 136 485 0 484 1 0 1 1 0 8 0 amappl8 128 476 0 436 2 0 2 2 0 8 0 amappl7 120 120 0 107 1 0 1 1 0 8 0 amappl6 112 27 0 21 1 0 1 1 0 8 0 amappl5 104 846 0 835 1 0 1 1 0 8 0 amappl4 96 683 0 653 1 0 1 1 0 8 0 amappl3 88 123 0 117 1 0 1 1 0 8 0 amappl2 80 6207 0 6144 2 0 2 2 0 8 0 amappl1 72 24508 0 24104 23 14 9 17 0 8 0 amappl 80 1981 0 1935 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 25 0 2 1 0 1 1 0 8 0 uaddrrnd 24 901 0 876 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 901 0 876 1 0 1 1 0 8 0 vmmpekpl 168 8986 0 8956 2 0 2 2 0 8 0 vmmpepl 168 109456 0 107448 154 52 102 120 0 357 13 vmsppl 272 900 0 876 2 0 2 2 0 8 0 pdppl 4096 1808 0 1763 8 2 6 7 0 8 0 pvpl 32 280360 0 262037 240 52 188 190 0 265 35 pmappl 200 900 0 876 4 2 2 2 0 8 0 extentpl 40 53 0 36 1 0 1 1 0 8 0 phpool 112 381 0 94 10 1 9 9 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(ffffffff823b30a4) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8053524600,34c,304,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac0100) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da70008,9,fffffd8053524500,0,0,ffff80001d718600) at tcp_usrreq+0xa54 sosend(fffffd805da70008,0,ffff80001d6caac8,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d718600,4,ffff80001d6caac8,0,ffff80001d6cabb0) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d718600,ffff80001d6cab60,ffff80001d6cabb0) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d6cac30) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffe67a0, 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(ffffffff823b30a4) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8053524600,34c,304,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac0100) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da70008,9,fffffd8053524500,0,0,ffff80001d718600) at tcp_usrreq+0xa54 sosend(fffffd805da70008,0,ffff80001d6caac8,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d718600,4,ffff80001d6caac8,0,ffff80001d6cabb0) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d718600,ffff80001d6cab60,ffff80001d6cabb0) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d6cac30) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffe67a0, count: -10