panic: m_copym0: short mbuf chain Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *434688 50659 0 0x12 0 0 sshd db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff821cc5f1) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8053f1f300,2d4,18c,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff8000009f5320) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805dad14b8,9,fffffd8053f1f200,0,0,ffff80001d797760) at tcp_usrreq+0xa54 sosend(fffffd805dad14b8,0,ffff80001d7481b8,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d797760,4,ffff80001d7481b8,0,ffff80001d7482a0) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d797760,ffff80001d748250,ffff80001d7482a0) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d748320) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7fffff6000, 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(ffffffff821cc5f1) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8053f1f300,2d4,18c,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff8000009f5320) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805dad14b8,9,fffffd8053f1f200,0,0,ffff80001d797760) at tcp_usrreq+0xa54 sosend(fffffd805dad14b8,0,ffff80001d7481b8,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d797760,4,ffff80001d7481b8,0,ffff80001d7482a0) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d797760,ffff80001d748250,ffff80001d7482a0) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d748320) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7fffff6000, count: -10 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff80001d747c80 rbx 0xffff80001d747d30 rdx 0x2 rcx 0 rax 0x1 r8 0xffffffff81638c7f kprintf+0x15f r9 0x1 r10 0x2 r11 0x1129c13ee90e981e r12 0x3000000008 r13 0xffff80001d747c90 r14 0x100 r15 0x1 rip 0xffffffff81c224d8 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff80001d747c70 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (sshd) pid=434688 stat=onproc flags process=12 proc=0 pri=24, usrpri=50, nice=20 forw=0xffffffffffffffff, list=0xffff80001d798390,0xffff80001d797290 process=0xffff8000ffff8748 user=0xffff80001d743000, vmspace=0xfffffd806bc09990 estcpu=0, cpticks=0, pctcpu=0.0 user=0, sys=0, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 81821 198268 36800 0 2 0 syz-executor.1 81821 213957 36800 0 2 0x4000000 syz-executor.1 56139 511325 0 0 3 0x14200 bored sosplice 80368 298595 89116 0 2 0x2 syz-executor.0 36800 309516 89116 0 2 0x482 syz-executor.1 89116 271586 11988 0 3 0x82 thrsleep syz-fuzzer 89116 24702 11988 0 2 0x4000482 syz-fuzzer 89116 22825 11988 0 3 0x4000082 thrsleep syz-fuzzer 89116 103791 11988 0 3 0x4000082 thrsleep syz-fuzzer 89116 402878 11988 0 3 0x4000082 thrsleep syz-fuzzer 89116 432917 11988 0 2 0x4000002 syz-fuzzer 89116 296507 11988 0 3 0x4000082 thrsleep syz-fuzzer 89116 51725 11988 0 3 0x4000082 thrsleep syz-fuzzer 11988 27580 50659 0 3 0x10008a pause ksh *50659 434688 23867 0 7 0x12 sshd 33750 402505 1 0 3 0x100083 ttyin getty 23867 94089 1 0 3 0x80 select sshd 92657 402861 51233 73 3 0x100090 kqread syslogd 51233 404151 1 0 3 0x100082 netio syslogd 97254 270177 1 77 3 0x100090 poll dhclient 27150 351837 1 0 3 0x80 poll dhclient 87962 361606 0 0 3 0x14200 bored smr 96762 91142 0 0 2 0x14200 zerothread 44240 418762 0 0 3 0x14200 aiodoned aiodoned 26919 192425 0 0 3 0x14200 syncer update 56555 337611 0 0 3 0x14200 cleaner cleaner 54568 125518 0 0 3 0x14200 reaper reaper 900 166082 0 0 3 0x14200 pgdaemon pagedaemon 92309 295775 0 0 3 0x14200 bored crynlk 38748 454168 0 0 3 0x14200 bored crypto 10253 274362 0 0 3 0x40014200 acpi0 acpi0 84005 347427 0 0 3 0x14200 bored softnet 46736 489511 0 0 3 0x14200 bored systqmp 91758 420215 0 0 3 0x14200 bored systq 62460 499134 0 0 3 0x40014200 bored softclock 16343 89830 0 0 3 0x40014200 idle0 1 292696 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 9497 6341K 6537K 78643K 10843 0 pcb 13 8K 8K 78643K 83 0 rtable 96 3K 7K 78643K 338 0 ifaddr 64 12K 12K 78643K 97 0 counters 21 16K 16K 78643K 23 0 ioctlops 0 0K 4K 78643K 37 0 iov 0 0K 16K 78643K 32 0 mount 1 1K 1K 78643K 1 0 vnodes 1219 77K 77K 78643K 1327 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 50 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1809 195K 288K 78643K 12938 0 file desc 5 13K 25K 78643K 202 0 proc 49 38K 63K 78643K 385 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 20 0 in_multi 32 2K 2K 78643K 105 0 ether_multi 1 0K 0K 78643K 11 0 mrt 0 0K 0K 78643K 2 0 ISOFS mount 1 32K 32K 78643K 1 0 MSDOSFS mount 1 16K 16K 78643K 1 0 ttys 55 254K 254K 78643K 55 0 exec 0 0K 1K 78643K 197 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 128 39K 55K 78643K 1333 0 UVM aobj 6 2K 2K 78643K 10 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 ip6_options 0 0K 0K 78643K 46 0 NDP 12 0K 0K 78643K 25 0 temp 91 3029K 3093K 78643K 19113 0 kqueue 3 4K 12K 78643K 41 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 37 0 35 1 0 1 1 0 8 0 rtentry 112 77 0 39 2 0 2 2 0 8 0 unpcb 120 95 0 87 1 0 1 1 0 8 0 syncache 264 4 0 4 1 1 0 1 0 8 0 tcpqe 32 499 0 499 1 1 0 1 0 8 0 tcpcb 544 207 0 203 1 0 1 1 0 8 0 ipq 40 2 0 2 1 0 1 1 0 8 1 ipqe 40 6 0 6 1 0 1 1 0 8 1 inpcb 280 387 0 380 2 0 2 2 0 8 1 nd6 48 14 0 12 1 0 1 1 0 8 0 pkpcb 40 2 0 2 1 0 1 1 0 8 1 ppxss 1128 1 0 1 1 1 0 1 0 8 0 pfrktable 1344 20 0 20 1 1 0 1 0 8 0 pftag 88 2 0 2 1 1 0 1 0 8 0 pfrule 1360 2 0 2 1 1 0 1 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 381 0 224 13 0 13 13 0 8 1 art_table 32 382 0 224 2 0 2 2 0 8 0 art_node 16 76 0 40 1 0 1 1 0 8 0 sysvmsgpl 40 1 0 0 1 0 1 1 0 8 0 semapl 112 34 0 24 1 0 1 1 0 8 0 shmpl 112 8 0 4 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 1694 0 295 88 0 88 88 0 8 0 ffsino 240 1694 0 295 83 0 83 83 0 8 0 nchpl 144 2210 0 619 60 0 60 60 0 8 0 uvmvnodes 72 1809 0 0 33 0 33 33 0 8 0 vnodes 208 1809 0 0 96 0 96 96 0 8 0 namei 1024 5969 0 5969 1 0 1 1 0 8 1 vcpupl 1984 2 0 0 1 0 1 1 0 8 0 vmpool 528 2 0 0 1 0 1 1 0 8 0 pfiaddrpl 120 6 0 6 1 1 0 1 0 8 0 scxspl 192 5823 0 5823 1 0 1 1 0 8 1 plimitpl 152 30 0 23 1 0 1 1 0 8 0 sigapl 424 389 0 360 4 0 4 4 0 8 0 futexpl 56 4057 0 4057 1 0 1 1 0 8 1 knotepl 112 104 0 85 1 0 1 1 0 8 0 kqueuepl 144 64 0 62 1 0 1 1 0 8 0 pipelkpl 16 90 0 80 1 0 1 1 0 8 0 pipepl 120 180 0 161 1 0 1 1 0 8 0 fdescpl 432 374 0 360 2 0 2 2 0 8 0 filepl 120 2336 0 2241 4 0 4 4 0 8 1 lockfpl 104 49 0 48 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 96 239 0 232 1 0 1 1 0 8 0 zombiepl 144 360 0 360 1 0 1 1 0 8 1 processpl 920 389 0 360 4 0 4 4 0 8 0 procpl 624 627 0 590 4 0 4 4 0 8 0 sosppl 128 2 0 2 1 0 1 1 0 8 1 sockpl 400 521 0 504 3 0 3 3 0 8 1 mcl64k 65536 523 0 523 65 6 59 65 0 8 59 mcl16k 16384 1 0 1 1 1 0 1 0 8 0 mcl12k 12288 4 0 4 1 0 1 1 0 8 1 mcl9k 9216 1 0 1 1 0 1 1 0 8 1 mcl8k 8192 5 0 5 1 0 1 1 0 8 1 mcl4k 4096 22 0 22 3 2 1 1 0 8 1 mcl2k 2048 71526 0 71461 21 12 9 18 0 8 0 mtagpl 80 17 0 2 2 1 1 1 0 8 0 mbufpl 256 115836 0 115593 43 21 22 40 0 8 0 bufpl 280 3671 0 126 254 0 254 254 0 8 0 anonpl 16 65438 0 50389 80 2 78 78 0 107 15 amapchunkpl 152 2155 0 2025 21 2 19 19 0 158 13 amappl16 192 2647 0 1810 62 12 50 55 0 8 8 amappl15 184 1 0 0 1 0 1 1 0 8 0 amappl14 176 27 0 19 1 0 1 1 0 8 0 amappl13 168 201 0 193 1 0 1 1 0 8 0 amappl12 160 3 0 3 1 1 0 1 0 8 0 amappl11 152 42 0 33 1 0 1 1 0 8 0 amappl10 144 100 0 94 1 0 1 1 0 8 0 amappl9 136 371 0 368 1 0 1 1 0 8 0 amappl8 128 339 0 292 2 0 2 2 0 8 0 amappl7 120 189 0 177 1 0 1 1 0 8 0 amappl6 112 22 0 18 1 0 1 1 0 8 0 amappl5 104 234 0 224 1 0 1 1 0 8 0 amappl4 96 508 0 480 1 0 1 1 0 8 0 amappl3 88 195 0 188 1 0 1 1 0 8 0 amappl2 80 2165 0 2101 2 0 2 2 0 8 0 amappl1 72 16289 0 15883 23 13 10 17 0 8 0 amappl 80 851 0 810 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 9 0 4 1 0 1 1 0 8 0 uaddrrnd 24 376 0 360 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 376 0 360 1 0 1 1 0 8 0 vmmpekpl 168 6478 0 6449 2 0 2 2 0 8 0 vmmpepl 168 52487 0 50563 119 19 100 105 0 357 12 vmsppl 272 375 0 360 3 1 2 2 0 8 0 pdppl 4096 758 0 722 6 1 5 6 0 8 0 pvpl 32 184290 0 166275 184 0 184 184 0 265 33 pmappl 200 375 0 360 1 0 1 1 0 8 0 extentpl 40 53 0 36 1 0 1 1 0 8 0 phpool 112 343 0 47 10 0 10 10 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(ffffffff821cc5f1) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8053f1f300,2d4,18c,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff8000009f5320) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805dad14b8,9,fffffd8053f1f200,0,0,ffff80001d797760) at tcp_usrreq+0xa54 sosend(fffffd805dad14b8,0,ffff80001d7481b8,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d797760,4,ffff80001d7481b8,0,ffff80001d7482a0) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d797760,ffff80001d748250,ffff80001d7482a0) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d748320) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7fffff6000, 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(ffffffff821cc5f1) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8053f1f300,2d4,18c,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff8000009f5320) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805dad14b8,9,fffffd8053f1f200,0,0,ffff80001d797760) at tcp_usrreq+0xa54 sosend(fffffd805dad14b8,0,ffff80001d7481b8,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d797760,4,ffff80001d7481b8,0,ffff80001d7482a0) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d797760,ffff80001d748250,ffff80001d7482a0) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d748320) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7fffff6000, count: -10