panic: m_copym0: short mbuf chain Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *316759 39301 0 0x12 0 0 sshd db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff823b285f) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd805c5b4f00,2ac,2a4,2) 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(fffffd805da69328,9,fffffd805c5b4e00,0,0,ffff80001d718120) at tcp_usrreq+0xa54 sosend(fffffd805da69328,0,ffff80001d71e568,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d718120,4,ffff80001d71e568,0,ffff80001d71e650) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d718120,ffff80001d71e600,ffff80001d71e650) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d71e6d0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7fffff00c0, 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(ffffffff823b285f) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd805c5b4f00,2ac,2a4,2) 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(fffffd805da69328,9,fffffd805c5b4e00,0,0,ffff80001d718120) at tcp_usrreq+0xa54 sosend(fffffd805da69328,0,ffff80001d71e568,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d718120,4,ffff80001d71e568,0,ffff80001d71e650) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d718120,ffff80001d71e600,ffff80001d71e650) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d71e6d0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7fffff00c0, count: -10 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff80001d71e030 rbx 0xffff80001d71e0e0 rdx 0x2 rcx 0 rax 0x1 r8 0xffffffff8118395f kprintf+0x15f r9 0x1 r10 0x2 r11 0x5dc0f366974c5755 r12 0x3000000008 r13 0xffff80001d71e040 r14 0x100 r15 0x1 rip 0xffffffff82075728 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff80001d71e020 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (sshd) pid=316759 stat=onproc flags process=12 proc=0 pri=24, usrpri=50, nice=20 forw=0xffffffffffffffff, list=0xffff80001d718ae0,0xffff80001d717290 process=0xffff8000ffff8018 user=0xffff80001d719000, vmspace=0xfffffd806bc0abb0 estcpu=0, cpticks=1, pctcpu=0.0 user=0, sys=0, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 81627 184805 92370 0 3 0x80 nanosleep syz-executor.1 81627 336958 92370 0 3 0x4000080 netcon syz-executor.1 81627 12327 92370 0 3 0x4000080 fsleep syz-executor.1 45111 350732 0 0 3 0x14200 bored sosplice 33049 100042 0 0 3 0x14200 acct acct 92370 421595 3647 0 3 0x82 nanosleep syz-executor.1 42258 18975 0 0 3 0x14280 nfsidl nfsio 8040 291992 0 0 3 0x14280 nfsidl nfsio 80156 50165 0 0 3 0x14280 nfsidl nfsio 59156 136937 0 0 3 0x14280 nfsidl nfsio 26862 39405 0 0 3 0x14280 nfsidl nfsio 14395 16811 0 0 3 0x14280 nfsidl nfsio 98914 333892 0 0 3 0x14280 nfsidl nfsio 87249 114141 0 0 3 0x14280 nfsidl nfsio 5483 359311 0 0 3 0x14280 nfsidl nfsio 94255 263938 0 0 3 0x14280 nfsidl nfsio 5959 178118 0 0 3 0x14280 nfsidl nfsio 36430 360851 0 0 3 0x14280 nfsidl nfsio 11269 509178 0 0 3 0x14280 nfsidl nfsio 40469 269532 0 0 3 0x14280 nfsidl nfsio 82955 373493 0 0 3 0x14280 nfsidl nfsio 57455 217579 0 0 3 0x14280 nfsidl nfsio 7890 71280 0 0 3 0x14280 nfsidl nfsio 19804 94331 0 0 3 0x14280 nfsidl nfsio 66775 193390 0 0 3 0x14280 nfsidl nfsio 2008 139564 0 0 3 0x14280 nfsidl nfsio 68293 340035 3647 0 2 0x2 syz-executor.0 3647 295745 25819 0 2 0x2 syz-fuzzer 3647 10799 25819 0 2 0x4000002 syz-fuzzer 3647 404186 25819 0 3 0x4000082 kqread syz-fuzzer 3647 63328 25819 0 3 0x4000082 thrsleep syz-fuzzer 3647 503627 25819 0 3 0x4000082 thrsleep syz-fuzzer 3647 15459 25819 0 2 0x4000002 syz-fuzzer 3647 302020 25819 0 3 0x4000082 thrsleep syz-fuzzer 3647 230771 25819 0 3 0x4000082 thrsleep syz-fuzzer 25819 195597 39301 0 3 0x10008a pause ksh *39301 316759 55146 0 7 0x12 sshd 77529 259025 1 0 3 0x100083 ttyin getty 55146 53255 1 0 3 0x80 select sshd 22409 332410 14685 73 3 0x100090 kqread syslogd 14685 47422 1 0 3 0x100082 netio syslogd 2793 225317 1 77 3 0x100090 poll dhclient 97787 142874 1 0 3 0x80 poll dhclient 13440 58031 0 0 3 0x14200 bored smr 95947 392357 0 0 3 0x14200 pgzero zerothread 74902 456731 0 0 3 0x14200 aiodoned aiodoned 13833 4896 0 0 3 0x14200 syncer update 21517 379 0 0 3 0x14200 cleaner cleaner 67659 21601 0 0 3 0x14200 reaper reaper 76931 476909 0 0 3 0x14200 pgdaemon pagedaemon 97024 374175 0 0 3 0x14200 bored crynlk 98026 120527 0 0 3 0x14200 bored crypto 11647 377680 0 0 3 0x40014200 acpi0 acpi0 60010 130326 0 0 3 0x14200 bored softnet 93649 477173 0 0 3 0x14200 bored systqmp 73196 186350 0 0 3 0x14200 bored systq 52362 408914 0 0 3 0x40014200 bored softclock 74770 417034 0 0 3 0x40014200 idle0 1 277269 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 9512 6539K 6595K 78643K 10915 0 pcb 13 8K 8K 78643K 57 0 rtable 103 6K 8K 78643K 429 0 ifaddr 78 16K 16K 78643K 254 0 counters 21 16K 16K 78643K 34 0 ioctlops 0 0K 4K 78643K 76 0 iov 0 0K 12K 78643K 36 0 mount 1 1K 1K 78643K 1 0 vnodes 1214 76K 77K 78643K 1338 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 30 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1809 195K 288K 78643K 12938 0 file desc 5 13K 25K 78643K 486 0 sigio 0 0K 0K 78643K 6 0 proc 49 38K 54K 78643K 415 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 64 3K 3K 78643K 108 0 ether_multi 1 0K 0K 78643K 6 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 49 228K 228K 78643K 49 0 exec 0 0K 1K 78643K 222 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 123 38K 40K 78643K 1923 0 UVM aobj 7 2K 2K 78643K 9 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 ip6_options 0 0K 0K 78643K 32 0 NDP 11 0K 0K 78643K 31 0 temp 91 3850K 3914K 78643K 7270 0 kqueue 3 4K 8K 78643K 19 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 5 1 0 1 1 0 8 0 rtpcb 80 29 0 27 1 0 1 1 0 8 0 rtentry 112 71 0 36 2 0 2 2 0 8 0 unpcb 120 137 0 129 1 0 1 1 0 8 0 syncache 264 6 0 6 2 2 0 1 0 8 0 tcpcb 544 346 0 341 1 0 1 1 0 8 0 inpcb 280 855 0 847 2 1 1 2 0 8 0 rttmr 72 3 0 3 1 0 1 1 0 8 1 nd6 48 11 0 9 1 0 1 1 0 8 0 ppxss 1128 1 0 1 1 1 0 1 0 8 0 pfstscr 40 1 0 0 1 0 1 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 32 0 26 1 0 1 1 0 8 0 pftag 88 1 0 0 1 0 1 1 0 8 0 pfstitem 24 1 0 0 1 0 1 1 0 8 0 pfstkey 112 1 0 0 1 0 1 1 0 8 0 pfstate 328 1 0 0 1 0 1 1 0 8 0 pfrule 1360 11 0 6 1 0 1 1 0 8 0 art_heap8 4096 2 0 0 2 0 2 2 0 8 0 art_heap4 256 296 0 130 13 0 13 13 0 8 2 art_table 32 298 0 130 2 0 2 2 0 8 0 art_node 16 70 0 37 1 0 1 1 0 8 0 sysvmsgpl 40 2 0 2 1 1 0 1 0 8 0 semupl 112 1 0 1 1 1 0 1 0 8 0 semapl 112 28 0 18 1 0 1 1 0 8 0 shmpl 112 7 0 2 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 1984 0 589 88 0 88 88 0 8 0 ffsino 240 1984 0 589 83 0 83 83 0 8 0 nchpl 144 2754 0 1172 60 0 60 60 0 8 0 uvmvnodes 72 2101 0 0 39 0 39 39 0 8 0 vnodes 208 2101 0 0 111 0 111 111 0 8 0 namei 1024 6939 0 6939 1 0 1 1 0 8 1 vcpupl 1984 2 0 0 1 0 1 1 0 8 0 vmpool 528 4 0 2 1 0 1 1 0 8 0 pfiaddrpl 120 12 0 8 1 0 1 1 0 8 0 scxspl 192 8338 0 8338 1 0 1 1 0 8 1 plimitpl 152 46 0 39 1 0 1 1 0 8 0 sigapl 424 691 0 641 6 0 6 6 0 8 0 futexpl 56 7408 0 7407 1 0 1 1 0 8 0 knotepl 112 98 0 79 1 0 1 1 0 8 0 kqueuepl 144 36 0 34 1 0 1 1 0 8 0 pipelkpl 16 114 0 104 1 0 1 1 0 8 0 pipepl 120 228 0 209 1 0 1 1 0 8 0 fdescpl 432 655 0 641 2 0 2 2 0 8 0 filepl 120 3130 0 3032 4 0 4 4 0 8 1 lockfpl 104 55 0 54 1 0 1 1 0 8 0 lockfspl 48 21 0 20 1 0 1 1 0 8 0 sessionpl 112 18 0 8 1 0 1 1 0 8 0 pgrppl 48 20 0 10 1 0 1 1 0 8 0 ucredpl 96 220 0 213 1 0 1 1 0 8 0 zombiepl 144 641 0 641 1 0 1 1 0 8 1 processpl 920 691 0 641 7 0 7 7 0 8 0 procpl 624 1196 0 1137 5 0 5 5 0 8 0 sosppl 128 2 0 2 1 0 1 1 0 8 1 sockpl 400 1021 0 1003 4 0 4 4 0 8 2 mcl64k 65536 20 0 20 1 0 1 1 0 8 1 mcl16k 16384 1 0 1 1 1 0 1 0 8 0 mcl12k 12288 11 0 11 1 0 1 1 0 8 1 mcl9k 9216 7 0 7 1 0 1 1 0 8 1 mcl8k 8192 8 0 8 1 0 1 1 0 8 1 mcl4k 4096 30 0 30 2 1 1 1 0 8 1 mcl2k 2048 77394 0 77343 21 13 8 17 0 8 1 mtagpl 80 25 0 22 2 1 1 1 0 8 0 mbufpl 256 125053 0 124980 12 1 11 11 0 8 5 bufpl 280 4211 0 128 292 0 292 292 0 8 0 anonpl 16 77945 0 61268 81 2 79 79 0 107 11 amapchunkpl 152 2915 0 2781 10 0 10 10 0 158 1 amappl16 192 3166 0 2238 53 0 53 53 0 8 6 amappl15 184 133 0 130 1 0 1 1 0 8 0 amappl14 176 23 0 19 1 0 1 1 0 8 0 amappl13 168 33 0 30 1 0 1 1 0 8 0 amappl12 160 63 0 62 1 0 1 1 0 8 0 amappl11 152 59 0 49 1 0 1 1 0 8 0 amappl10 144 269 0 264 1 0 1 1 0 8 0 amappl9 136 371 0 370 1 0 1 1 0 8 0 amappl8 128 352 0 312 2 0 2 2 0 8 0 amappl7 120 110 0 99 1 0 1 1 0 8 0 amappl6 112 32 0 24 1 0 1 1 0 8 0 amappl5 104 643 0 630 1 0 1 1 0 8 0 amappl4 96 439 0 413 1 0 1 1 0 8 0 amappl3 88 112 0 106 1 0 1 1 0 8 0 amappl2 80 4475 0 4408 2 0 2 2 0 8 0 amappl1 72 20843 0 20425 24 15 9 17 0 8 0 amappl 80 1420 0 1378 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 8 0 2 1 0 1 1 0 8 0 uaddrrnd 24 659 0 643 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 659 0 643 1 0 1 1 0 8 0 vmmpekpl 168 7746 0 7710 2 0 2 2 0 8 0 vmmpepl 168 82753 0 80734 126 11 115 120 0 357 27 vmsppl 272 658 0 643 2 0 2 2 0 8 0 pdppl 4096 1324 0 1288 6 1 5 6 0 8 0 pvpl 32 224868 0 205087 189 1 188 188 0 265 27 pmappl 200 658 0 643 1 0 1 1 0 8 0 extentpl 40 53 0 36 1 0 1 1 0 8 0 phpool 112 249 0 19 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(ffffffff823b285f) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd805c5b4f00,2ac,2a4,2) 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(fffffd805da69328,9,fffffd805c5b4e00,0,0,ffff80001d718120) at tcp_usrreq+0xa54 sosend(fffffd805da69328,0,ffff80001d71e568,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d718120,4,ffff80001d71e568,0,ffff80001d71e650) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d718120,ffff80001d71e600,ffff80001d71e650) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d71e6d0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7fffff00c0, 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(ffffffff823b285f) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd805c5b4f00,2ac,2a4,2) 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(fffffd805da69328,9,fffffd805c5b4e00,0,0,ffff80001d718120) at tcp_usrreq+0xa54 sosend(fffffd805da69328,0,ffff80001d71e568,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d718120,4,ffff80001d71e568,0,ffff80001d71e650) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d718120,ffff80001d71e600,ffff80001d71e650) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d71e6d0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7fffff00c0, count: -10