panic: m_copym0: short mbuf chain Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *166363 54519 0 0x12 0 0 sshd db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff823b1e1a) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8053c0a700,3e4,16c,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000abfcc0) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da78008,9,fffffd8053c0a600,0,0,ffff80001d717c40) at tcp_usrreq+0xa54 sosend(fffffd805da78008,0,ffff80001d6cabf8,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d717c40,4,ffff80001d6cabf8,0,ffff80001d6cace0) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d717c40,ffff80001d6cac90,ffff80001d6cace0) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d6cad60) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffcd010, 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(ffffffff823b1e1a) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8053c0a700,3e4,16c,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000abfcc0) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da78008,9,fffffd8053c0a600,0,0,ffff80001d717c40) at tcp_usrreq+0xa54 sosend(fffffd805da78008,0,ffff80001d6cabf8,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d717c40,4,ffff80001d6cabf8,0,ffff80001d6cace0) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d717c40,ffff80001d6cac90,ffff80001d6cace0) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d6cad60) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffcd010, count: -10 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff80001d6ca6c0 rbx 0xffff80001d6ca770 rdx 0x2 rcx 0 rax 0x1 r8 0xffffffff8193eacf kprintf+0x15f r9 0x1 r10 0x2 r11 0x289f2890f36c98d0 r12 0x3000000008 r13 0xffff80001d6ca6d0 r14 0x100 r15 0x1 rip 0xffffffff81a55c98 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff80001d6ca6b0 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (sshd) pid=166363 stat=onproc flags process=12 proc=0 pri=50, usrpri=50, nice=20 forw=0xffffffffffffffff, list=0xffff80001d718ae0,0xffff80001d717500 process=0xffff8000ffff8748 user=0xffff80001d6c5000, vmspace=0xfffffd806bc09aa0 estcpu=0, cpticks=0, pctcpu=0.0 user=0, sys=0, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 49456 93426 24935 0 2 0 syz-executor.0 86744 308482 0 0 3 0x14280 nfsidl nfsio 60913 214753 0 0 3 0x14280 nfsidl nfsio 18038 170527 0 0 3 0x14280 nfsidl nfsio 54780 66323 0 0 3 0x14280 nfsidl nfsio 8470 455827 0 0 3 0x14280 nfsidl nfsio 45776 361833 0 0 3 0x14280 nfsidl nfsio 42670 133440 0 0 3 0x14280 nfsidl nfsio 13198 266616 0 0 3 0x14280 nfsidl nfsio 58022 392359 0 0 3 0x14280 nfsidl nfsio 34206 332868 0 0 3 0x14280 nfsidl nfsio 32356 34699 0 0 3 0x14280 nfsidl nfsio 24666 345326 0 0 3 0x14280 nfsidl nfsio 85864 215896 0 0 3 0x14280 nfsidl nfsio 53250 328739 0 0 3 0x14280 nfsidl nfsio 39882 63802 0 0 3 0x14280 nfsidl nfsio 60714 271664 0 0 3 0x14280 nfsidl nfsio 8755 512614 0 0 3 0x14280 nfsidl nfsio 29856 112156 0 0 3 0x14280 nfsidl nfsio 90693 10253 0 0 3 0x14280 nfsidl nfsio 3692 385326 0 0 3 0x14280 nfsidl nfsio 57243 280575 0 0 3 0x14200 bored sosplice 28845 510879 0 0 3 0x14200 acct acct 56168 322814 34889 0 2 0x2 syz-executor.1 24935 236590 34889 0 3 0x82 nanosleep syz-executor.0 34889 164757 94553 0 3 0x82 thrsleep syz-fuzzer 34889 394532 94553 0 3 0x4000082 nanosleep syz-fuzzer 34889 517553 94553 0 3 0x4000082 thrsleep syz-fuzzer 34889 344000 94553 0 3 0x4000082 thrsleep syz-fuzzer 34889 383049 94553 0 3 0x4000082 thrsleep syz-fuzzer 34889 476010 94553 0 3 0x4000082 kqread syz-fuzzer 34889 379948 94553 0 3 0x4000082 thrsleep syz-fuzzer 34889 69198 94553 0 3 0x4000082 thrsleep syz-fuzzer 94553 490830 54519 0 3 0x10008a pause ksh *54519 166363 92498 0 7 0x12 sshd 3274 438585 1 0 3 0x100083 ttyin getty 92498 418148 1 0 3 0x80 select sshd 56863 430322 21417 73 3 0x100090 kqread syslogd 21417 130546 1 0 3 0x100082 netio syslogd 99409 327510 1 77 3 0x100090 poll dhclient 20457 454477 1 0 3 0x80 poll dhclient 47757 202914 0 0 3 0x14200 bored smr 57129 208981 0 0 3 0x14200 pgzero zerothread 84166 43857 0 0 3 0x14200 aiodoned aiodoned 28451 265539 0 0 3 0x14200 syncer update 67583 283696 0 0 3 0x14200 cleaner cleaner 53478 215023 0 0 3 0x14200 reaper reaper 98869 427163 0 0 3 0x14200 pgdaemon pagedaemon 70787 427642 0 0 3 0x14200 bored crynlk 89593 438843 0 0 3 0x14200 bored crypto 98303 230676 0 0 3 0x40014200 acpi0 acpi0 97241 268091 0 0 3 0x14200 bored softnet 51103 235168 0 0 3 0x14200 bored systqmp 30526 304789 0 0 3 0x14200 bored systq 47863 418821 0 0 3 0x40014200 bored softclock 35802 450599 0 0 3 0x40014200 idle0 1 105578 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 9502 6352K 6852K 78643K 10895 0 pcb 13 8K 8K 78643K 54 0 rtable 114 7K 8K 78643K 409 0 ifaddr 74 14K 15K 78643K 150 0 counters 21 16K 16K 78643K 28 0 ioctlops 0 0K 4K 78643K 41 0 iov 0 0K 12K 78643K 268 0 mount 1 1K 1K 78643K 1 0 vnodes 1218 77K 77K 78643K 1301 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 40 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1809 195K 288K 78643K 12938 0 file desc 5 13K 25K 78643K 206 0 sigio 0 0K 0K 78643K 2 0 proc 49 38K 63K 78643K 376 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 13 0 in_multi 32 2K 2K 78643K 62 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 43 201K 201K 78643K 43 0 exec 0 0K 1K 78643K 217 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 114 22K 42K 78643K 1335 0 UVM aobj 10 2K 2K 78643K 12 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 ip6_options 0 0K 0K 78643K 36 0 NDP 12 0K 0K 78643K 25 0 temp 99 3851K 3915K 78643K 2405 0 kqueue 3 4K 8K 78643K 20 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 29 0 27 1 0 1 1 0 8 0 rtentry 112 64 0 26 2 0 2 2 0 8 0 unpcb 120 85 0 77 1 0 1 1 0 8 0 syncache 264 10 0 10 3 2 1 1 0 8 1 tcpqe 32 510 0 510 1 1 0 1 0 8 0 tcpcb 544 91 0 87 1 0 1 1 0 8 0 inpcb 280 235 0 228 2 1 1 2 0 8 0 nd6 48 8 0 6 1 0 1 1 0 8 0 ppxss 1128 3 0 3 1 1 0 1 0 8 0 pfrktable 1344 57 0 48 1 0 1 1 0 8 0 pftag 88 8 0 4 1 0 1 1 0 8 0 pfrule 1360 16 0 10 1 0 1 1 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 256 0 93 13 1 12 13 0 8 0 art_table 32 257 0 93 2 0 2 2 0 8 0 art_node 16 63 0 27 1 0 1 1 0 8 0 sysvmsgpl 40 4 0 3 1 0 1 1 0 8 0 semupl 112 1 0 1 1 1 0 1 0 8 0 semapl 112 38 0 28 1 0 1 1 0 8 0 shmpl 112 10 0 2 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 1663 0 265 88 0 88 88 0 8 0 ffsino 240 1663 0 265 83 0 83 83 0 8 0 nchpl 144 2257 0 668 60 0 60 60 0 8 0 uvmvnodes 72 1765 0 0 33 0 33 33 0 8 0 vnodes 208 1765 0 0 93 0 93 93 0 8 0 namei 1024 5801 0 5801 2 1 1 1 0 8 1 vmpool 528 1 0 1 1 1 0 1 0 8 0 pfiaddrpl 120 24 0 16 1 0 1 1 0 8 0 scxspl 192 6450 0 6450 1 0 1 1 0 8 1 plimitpl 152 24 0 17 1 0 1 1 0 8 0 sigapl 424 414 0 364 6 0 6 6 0 8 0 futexpl 56 4228 0 4228 1 0 1 1 0 8 1 knotepl 112 89 0 70 1 0 1 1 0 8 0 kqueuepl 144 32 0 29 1 0 1 1 0 8 0 pipelkpl 16 96 0 86 1 0 1 1 0 8 0 pipepl 120 192 0 173 1 0 1 1 0 8 0 fdescpl 432 378 0 364 2 0 2 2 0 8 0 filepl 120 2290 0 2195 4 0 4 4 0 8 1 lockfpl 104 43 0 42 1 0 1 1 0 8 0 lockfspl 48 18 0 17 1 0 1 1 0 8 0 sessionpl 112 17 0 7 1 0 1 1 0 8 0 pgrppl 48 19 0 9 1 0 1 1 0 8 0 ucredpl 96 185 0 178 1 0 1 1 0 8 0 zombiepl 144 364 0 364 2 1 1 1 0 8 1 processpl 920 414 0 364 7 0 7 7 0 8 0 procpl 624 660 0 603 5 0 5 5 0 8 0 sosppl 128 4 0 4 1 1 0 1 0 8 0 sockpl 400 350 0 333 4 1 3 3 0 8 1 mcl64k 65536 30 0 30 2 1 1 1 0 8 1 mcl16k 16384 3 0 3 2 1 1 1 0 8 1 mcl12k 12288 14 0 14 2 1 1 1 0 8 1 mcl9k 9216 1 0 1 1 1 0 1 0 8 0 mcl8k 8192 14 0 14 2 1 1 1 0 8 1 mcl4k 4096 25 0 25 3 2 1 1 0 8 1 mcl2k 2048 75046 0 74986 22 14 8 20 0 8 0 mtagpl 80 21 0 4 2 1 1 1 0 8 0 mbufpl 256 120679 0 120529 16 5 11 14 0 8 0 bufpl 280 3702 0 126 256 0 256 256 0 8 0 anonpl 16 55611 0 40702 77 11 66 74 0 107 1 amapchunkpl 152 2189 0 2057 20 9 11 19 0 158 5 amappl16 192 2029 0 1161 52 6 46 50 0 8 2 amappl15 184 10 0 8 1 0 1 1 0 8 0 amappl14 176 22 0 19 1 0 1 1 0 8 0 amappl13 168 34 0 30 1 0 1 1 0 8 0 amappl12 160 10 0 8 1 0 1 1 0 8 0 amappl11 152 45 0 36 1 0 1 1 0 8 0 amappl10 144 100 0 95 1 0 1 1 0 8 0 amappl9 136 454 0 451 1 0 1 1 0 8 0 amappl8 128 407 0 369 2 0 2 2 0 8 0 amappl7 120 194 0 182 1 0 1 1 0 8 0 amappl6 112 23 0 19 1 0 1 1 0 8 0 amappl5 104 317 0 307 1 0 1 1 0 8 0 amappl4 96 424 0 395 1 0 1 1 0 8 0 amappl3 88 116 0 111 1 0 1 1 0 8 0 amappl2 80 2196 0 2141 2 0 2 2 0 8 0 amappl1 72 16531 0 16132 23 14 9 17 0 8 0 amappl 80 866 0 825 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 11 0 2 1 0 1 1 0 8 0 uaddrrnd 24 379 0 365 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 379 0 365 1 0 1 1 0 8 0 vmmpekpl 168 6675 0 6647 3 1 2 2 0 8 0 vmmpepl 168 51878 0 49969 117 25 92 105 0 357 7 vmsppl 272 378 0 365 2 1 1 2 0 8 0 pdppl 4096 764 0 730 6 1 5 6 0 8 0 pvpl 32 169599 0 151683 180 16 164 176 0 265 8 pmappl 200 378 0 365 1 0 1 1 0 8 0 extentpl 40 53 0 36 1 0 1 1 0 8 0 phpool 112 258 0 31 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(ffffffff823b1e1a) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8053c0a700,3e4,16c,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000abfcc0) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da78008,9,fffffd8053c0a600,0,0,ffff80001d717c40) at tcp_usrreq+0xa54 sosend(fffffd805da78008,0,ffff80001d6cabf8,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d717c40,4,ffff80001d6cabf8,0,ffff80001d6cace0) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d717c40,ffff80001d6cac90,ffff80001d6cace0) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d6cad60) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffcd010, 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(ffffffff823b1e1a) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8053c0a700,3e4,16c,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000abfcc0) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da78008,9,fffffd8053c0a600,0,0,ffff80001d717c40) at tcp_usrreq+0xa54 sosend(fffffd805da78008,0,ffff80001d6cabf8,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d717c40,4,ffff80001d6cabf8,0,ffff80001d6cace0) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d717c40,ffff80001d6cac90,ffff80001d6cace0) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d6cad60) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffcd010, count: -10