panic: m_copym0: short mbuf chain Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *266705 43515 0 0x12 0 0 sshd db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff823cb4a7) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd805f417e00,62c,464,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac2980) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da6b4b8,9,fffffd805f417d00,0,0,ffff80001d71c010) at tcp_usrreq+0xa54 sosend(fffffd805da6b4b8,0,ffff80001d722fe8,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:555 dofilewritev(ffff80001d71c010,4,ffff80001d722fe8,0,ffff80001d7230d0) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d71c010,ffff80001d723080,ffff80001d7230d0) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d723150) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffc6620, 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(ffffffff823cb4a7) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd805f417e00,62c,464,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac2980) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da6b4b8,9,fffffd805f417d00,0,0,ffff80001d71c010) at tcp_usrreq+0xa54 sosend(fffffd805da6b4b8,0,ffff80001d722fe8,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:555 dofilewritev(ffff80001d71c010,4,ffff80001d722fe8,0,ffff80001d7230d0) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d71c010,ffff80001d723080,ffff80001d7230d0) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d723150) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffc6620, count: -10 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff80001d722ab0 rbx 0xffff80001d722b60 rdx 0x2 rcx 0 rax 0x1 r8 0xffffffff81eca81f kprintf+0x15f r9 0x1 r10 0x2 r11 0xb9a3e3e5a40775b6 r12 0x3000000008 r13 0xffff80001d722ac0 r14 0x100 r15 0x1 rip 0xffffffff81dacd88 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff80001d722aa0 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (sshd) pid=266705 stat=onproc flags process=12 proc=0 pri=24, usrpri=50, nice=20 forw=0xffffffffffffffff, list=0xffff80001d71d870,0xffff80001d71c500 process=0xffff80001d706018 user=0xffff80001d71e000, vmspace=0xfffffd806bc09990 estcpu=0, cpticks=0, pctcpu=0.1 user=0, sys=0, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 82245 71806 93726 0 2 0 syz-executor.1 82245 374867 93726 0 2 0x4000000 syz-executor.1 58099 183575 0 0 3 0x14200 bored sosplice 93726 316606 17167 0 3 0x82 nanosleep syz-executor.1 78925 389593 17167 0 2 0x2 syz-executor.0 17167 474985 35300 0 3 0x82 thrsleep syz-fuzzer 17167 69454 35300 0 2 0x4000002 syz-fuzzer 17167 62697 35300 0 3 0x4000082 thrsleep syz-fuzzer 17167 335590 35300 0 3 0x4000082 thrsleep syz-fuzzer 17167 114814 35300 0 3 0x4000082 thrsleep syz-fuzzer 17167 323239 35300 0 3 0x4000082 thrsleep syz-fuzzer 17167 313689 35300 0 3 0x4000082 thrsleep syz-fuzzer 17167 429298 35300 0 2 0x4000002 syz-fuzzer 35300 371328 43515 0 3 0x10008a pause ksh *43515 266705 46424 0 7 0x12 sshd 39442 223184 1 0 3 0x100083 ttyin getty 46424 32579 1 0 3 0x80 select sshd 79202 264441 78938 73 3 0x100090 kqread syslogd 78938 492667 1 0 3 0x100082 netio syslogd 71651 450257 1 77 3 0x100090 poll dhclient 37827 340316 1 0 3 0x80 poll dhclient 11018 87323 0 0 3 0x14200 bored smr 27093 396882 0 0 2 0x14200 zerothread 34503 228930 0 0 3 0x14200 aiodoned aiodoned 68299 267092 0 0 3 0x14200 syncer update 6461 175316 0 0 3 0x14200 cleaner cleaner 18852 117173 0 0 3 0x14200 reaper reaper 88037 380415 0 0 3 0x14200 pgdaemon pagedaemon 2303 467154 0 0 3 0x14200 bored crynlk 58018 219923 0 0 3 0x14200 bored crypto 56894 211589 0 0 3 0x40014200 acpi0 acpi0 69512 155170 0 0 3 0x14200 bored softnet 96092 85651 0 0 3 0x14200 bored systqmp 55807 39832 0 0 3 0x14200 bored systq 68693 466868 0 0 3 0x40014200 bored softclock 9228 244789 0 0 3 0x40014200 idle0 1 492815 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 9483 6344K 6602K 78643K 10787 0 pcb 13 8K 8K 78643K 45 0 rtable 116 5K 9K 78643K 442 0 ifaddr 63 13K 14K 78643K 151 0 counters 21 16K 16K 78643K 24 0 ioctlops 0 0K 4K 78643K 47 0 iov 0 0K 16K 78643K 20 0 mount 1 1K 1K 78643K 1 0 vnodes 1225 77K 77K 78643K 1300 0 UFS quota 1 32K 32K 78643K 1 0 UFS mount 5 36K 36K 78643K 5 0 shm 2 1K 5K 78643K 7 0 VM map 2 0K 0K 78643K 2 0 sem 12 1K 1K 78643K 18 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1809 195K 288K 78643K 12938 0 file desc 5 13K 25K 78643K 163 0 sigio 0 0K 0K 78643K 2 0 proc 48 38K 63K 78643K 386 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 379 0 in_multi 40 2K 2K 78643K 50 0 ether_multi 1 0K 0K 78643K 2 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 191 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 127 39K 39K 78643K 1217 0 UVM aobj 9 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 32 0 NDP 9 0K 0K 78643K 18 0 temp 88 3852K 3916K 78643K 3740 0 kqueue 3 4K 8K 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 6 0 0 1 0 1 1 0 8 0 rtpcb 80 25 0 23 1 0 1 1 0 8 0 rtentry 112 47 0 3 2 0 2 2 0 8 0 unpcb 120 73 0 65 1 0 1 1 0 8 0 syncache 264 6 0 6 2 1 1 1 0 8 1 tcpqe 32 111 0 111 1 0 1 1 0 8 1 tcpcb 544 56 0 50 1 0 1 1 0 8 0 inpcb 296 273 0 264 2 0 2 2 0 8 1 nd6 48 8 0 2 1 0 1 1 0 8 0 pfrktable 1344 107 0 102 2 0 2 2 0 8 1 pftag 88 24 0 22 1 0 1 1 0 8 0 pfrule 1360 19 0 16 1 0 1 1 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 188 0 0 12 0 12 12 0 8 0 art_table 32 189 0 0 2 0 2 2 0 8 0 art_node 16 46 0 6 1 0 1 1 0 8 0 sysvmsgpl 40 17 0 8 1 0 1 1 0 8 0 semapl 112 16 0 6 1 0 1 1 0 8 0 shmpl 112 8 0 2 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 1609 0 211 88 0 88 88 0 8 0 ffsino 240 1609 0 211 83 0 83 83 0 8 0 nchpl 144 2063 0 460 60 0 60 60 0 8 0 uvmvnodes 72 1705 0 0 31 0 31 31 0 8 0 vnodes 208 1705 0 0 90 0 90 90 0 8 0 namei 1024 5374 0 5374 1 0 1 1 0 8 1 vcpupl 1984 1 0 0 1 0 1 1 0 8 0 vmpool 528 1 0 0 1 0 1 1 0 8 0 pfiaddrpl 120 34 0 30 1 0 1 1 0 8 0 scxspl 192 6034 0 6034 1 0 1 1 0 8 1 plimitpl 152 28 0 21 1 0 1 1 0 8 0 sigapl 424 350 0 321 4 0 4 4 0 8 0 futexpl 56 3260 0 3260 1 0 1 1 0 8 1 knotepl 112 87 0 68 1 0 1 1 0 8 0 kqueuepl 144 30 0 28 1 0 1 1 0 8 0 pipepl 272 91 0 81 1 0 1 1 0 8 0 fdescpl 432 335 0 321 2 0 2 2 0 8 0 filepl 120 2065 0 1970 4 0 4 4 0 8 1 lockfpl 104 33 0 32 1 0 1 1 0 8 0 lockfspl 48 13 0 12 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 96 171 0 164 1 0 1 1 0 8 0 zombiepl 144 321 0 321 1 0 1 1 0 8 1 processpl 928 350 0 321 4 0 4 4 0 8 0 procpl 624 517 0 480 4 0 4 4 0 8 0 sosppl 128 2 0 2 1 0 1 1 0 8 1 sockpl 400 371 0 352 3 0 3 3 0 8 1 mcl64k 65536 10 0 10 1 0 1 1 0 8 1 mcl16k 16384 1 0 1 1 0 1 1 0 8 1 mcl12k 12288 4 0 4 1 0 1 1 0 8 1 mcl9k 9216 2 0 2 1 0 1 1 0 8 1 mcl8k 8192 2 0 2 1 0 1 1 0 8 1 mcl4k 4096 26 0 26 2 1 1 1 0 8 1 mcl2k2 2112 1 0 1 1 0 1 1 0 8 1 mcl2k 2048 77341 0 77302 12 4 8 12 0 8 2 mtagpl 96 7 0 2 2 1 1 1 0 8 0 mbufpl 256 123310 0 123200 12 2 10 10 0 8 0 bufpl 280 3593 0 126 248 0 248 248 0 8 0 anonpl 16 45273 0 29121 69 2 67 67 0 107 0 amapchunkpl 152 1424 0 1297 8 2 6 8 0 158 0 amappl16 192 1449 0 554 46 0 46 46 0 8 1 amappl15 184 69 0 65 1 0 1 1 0 8 0 amappl14 176 28 0 21 1 0 1 1 0 8 0 amappl13 168 92 0 88 1 0 1 1 0 8 0 amappl12 160 68 0 65 1 0 1 1 0 8 0 amappl11 152 44 0 35 1 0 1 1 0 8 0 amappl10 144 76 0 71 1 0 1 1 0 8 0 amappl9 136 374 0 372 1 0 1 1 0 8 0 amappl8 128 326 0 286 2 0 2 2 0 8 0 amappl7 120 172 0 159 1 0 1 1 0 8 0 amappl6 112 29 0 19 1 0 1 1 0 8 0 amappl5 104 271 0 260 1 0 1 1 0 8 0 amappl4 96 418 0 393 1 0 1 1 0 8 0 amappl3 88 107 0 102 1 0 1 1 0 8 0 amappl2 80 1923 0 1855 2 0 2 2 0 8 0 amappl1 72 15667 0 15256 23 13 10 17 0 8 0 amappl 80 735 0 695 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 2 1 0 1 1 0 8 0 uaddrrnd 24 336 0 321 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 336 0 321 1 0 1 1 0 8 0 vmmpekpl 168 6204 0 6175 2 0 2 2 0 8 0 vmmpepl 168 47163 0 45170 116 8 108 111 0 357 21 vmsppl 272 335 0 321 2 0 2 2 0 8 1 pdppl 4096 678 0 643 6 1 5 6 0 8 0 pvpl 32 152661 0 133540 161 0 161 161 0 265 5 pmappl 200 335 0 321 1 0 1 1 0 8 0 extentpl 40 53 0 36 1 0 1 1 0 8 0 phpool 112 237 0 10 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(ffffffff823cb4a7) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd805f417e00,62c,464,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac2980) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da6b4b8,9,fffffd805f417d00,0,0,ffff80001d71c010) at tcp_usrreq+0xa54 sosend(fffffd805da6b4b8,0,ffff80001d722fe8,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:555 dofilewritev(ffff80001d71c010,4,ffff80001d722fe8,0,ffff80001d7230d0) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d71c010,ffff80001d723080,ffff80001d7230d0) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d723150) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffc6620, 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(ffffffff823cb4a7) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd805f417e00,62c,464,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ac2980) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805da6b4b8,9,fffffd805f417d00,0,0,ffff80001d71c010) at tcp_usrreq+0xa54 sosend(fffffd805da6b4b8,0,ffff80001d722fe8,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:555 dofilewritev(ffff80001d71c010,4,ffff80001d722fe8,0,ffff80001d7230d0) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d71c010,ffff80001d723080,ffff80001d7230d0) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d723150) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffc6620, count: -10