panic: m_copym0: short mbuf chain Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *192454 10157 0 0x12 0 0 sshd db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff823aed46) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8069b5f500,53c,384,2) 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(fffffd805da704b8,9,fffffd8069b5f400,0,0,ffff80001d717010) at tcp_usrreq+0xa54 sosend(fffffd805da704b8,0,ffff80001d71ec98,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d717010,4,ffff80001d71ec98,0,ffff80001d71ed80) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d717010,ffff80001d71ed30,ffff80001d71ed80) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d71ee00) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffe3970, 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(ffffffff823aed46) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8069b5f500,53c,384,2) 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(fffffd805da704b8,9,fffffd8069b5f400,0,0,ffff80001d717010) at tcp_usrreq+0xa54 sosend(fffffd805da704b8,0,ffff80001d71ec98,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d717010,4,ffff80001d71ec98,0,ffff80001d71ed80) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d717010,ffff80001d71ed30,ffff80001d71ed80) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d71ee00) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffe3970, count: -10 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff80001d71e760 rbx 0xffff80001d71e810 rdx 0x2 rcx 0 rax 0x1 r8 0xffffffff814fdcef kprintf+0x15f r9 0x1 r10 0x2 r11 0x698dae66c7817694 r12 0x3000000008 r13 0xffff80001d71e770 r14 0x100 r15 0x1 rip 0xffffffff82018d68 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff80001d71e750 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (sshd) pid=192454 stat=onproc flags process=12 proc=0 pri=24, usrpri=50, nice=20 forw=0xffffffffffffffff, list=0xffff80001d717760,0xffff80001d717500 process=0xffff8000ffff83b0 user=0xffff80001d719000, vmspace=0xfffffd806bc09770 estcpu=0, cpticks=0, pctcpu=0.0 user=0, sys=0, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 97574 124762 19408 0 2 0 syz-executor.1 97574 139686 19408 0 2 0x4000000 syz-executor.1 20125 238376 7966 0 2 0x2 syz-executor.0 22148 493120 1 0 3 0x100083 ttyin getty 32939 208296 0 0 3 0x14200 acct acct 45510 119226 0 0 3 0x14280 nfsidl nfsio 53039 435595 0 0 3 0x14280 nfsidl nfsio 52709 409381 0 0 3 0x14280 nfsidl nfsio 99216 286384 0 0 3 0x14280 nfsidl nfsio 61421 389525 0 0 3 0x14280 nfsidl nfsio 12720 232881 0 0 3 0x14280 nfsidl nfsio 20374 386968 0 0 3 0x14280 nfsidl nfsio 31630 253461 0 0 3 0x14280 nfsidl nfsio 95077 493278 0 0 3 0x14280 nfsidl nfsio 48250 341430 0 0 3 0x14280 nfsidl nfsio 19486 43450 0 0 3 0x14280 nfsidl nfsio 69810 114432 0 0 3 0x14280 nfsidl nfsio 1217 206477 0 0 3 0x14280 nfsidl nfsio 32844 339094 0 0 3 0x14280 nfsidl nfsio 9543 117916 0 0 3 0x14280 nfsidl nfsio 37311 69562 0 0 3 0x14280 nfsidl nfsio 12675 207024 0 0 3 0x14280 nfsidl nfsio 97976 26459 0 0 3 0x14280 nfsidl nfsio 26623 452535 0 0 3 0x14280 nfsidl nfsio 57527 297108 0 0 3 0x14280 nfsidl nfsio 30540 355416 0 0 3 0x14200 bored sosplice 19408 316561 7966 0 3 0x82 nanosleep syz-executor.1 7966 194545 45058 0 3 0x82 thrsleep syz-fuzzer 7966 294874 45058 0 3 0x4000082 nanosleep syz-fuzzer 7966 233555 45058 0 3 0x4000082 thrsleep syz-fuzzer 7966 514770 45058 0 3 0x4000082 thrsleep syz-fuzzer 7966 299944 45058 0 3 0x4000082 thrsleep syz-fuzzer 7966 372605 45058 0 2 0x4000002 syz-fuzzer 7966 246139 45058 0 3 0x4000082 thrsleep syz-fuzzer 7966 339874 45058 0 3 0x4000082 thrsleep syz-fuzzer 45058 351698 10157 0 3 0x10008a pause ksh *10157 192454 40149 0 7 0x12 sshd 40149 619 1 0 3 0x80 select sshd 37955 111378 10915 73 3 0x100090 kqread syslogd 10915 191299 1 0 3 0x100082 netio syslogd 61931 220187 1 77 3 0x100090 poll dhclient 59502 172668 1 0 3 0x80 poll dhclient 2004 407560 0 0 3 0x14200 bored smr 74011 291084 0 0 2 0x14200 zerothread 94098 58002 0 0 3 0x14200 aiodoned aiodoned 62766 443735 0 0 3 0x14200 syncer update 63493 2289 0 0 3 0x14200 cleaner cleaner 61972 385227 0 0 3 0x14200 reaper reaper 36417 257494 0 0 3 0x14200 pgdaemon pagedaemon 60080 337654 0 0 3 0x14200 bored crynlk 37529 262230 0 0 3 0x14200 bored crypto 72111 94405 0 0 3 0x40014200 acpi0 acpi0 54500 413354 0 0 3 0x14200 bored softnet 64058 87081 0 0 3 0x14200 bored systqmp 76387 121064 0 0 3 0x14200 bored systq 46500 334857 0 0 3 0x40014200 bored softclock 33018 462429 0 0 3 0x40014200 idle0 1 325467 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 9523 6374K 6877K 78643K 12095 0 pcb 13 8K 8K 78643K 420 0 rtable 110 14K 19K 78643K 1307 0 ifaddr 109 22K 23K 78643K 363 0 sysctl 2 0K 0K 78643K 2 0 counters 21 16K 16K 78643K 41 0 ioctlops 0 0K 4K 78643K 177 0 iov 0 0K 32K 78643K 157 0 mount 1 1K 1K 78643K 1 0 vnodes 1222 77K 77K 78643K 1803 0 UFS quota 1 32K 32K 78643K 1 0 UFS mount 5 36K 36K 78643K 5 0 shm 2 1K 5K 78643K 10 0 VM map 2 0K 0K 78643K 2 0 sem 12 0K 0K 78643K 172 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1809 195K 288K 78643K 12938 0 file desc 5 13K 25K 78643K 1180 0 sigio 0 0K 0K 78643K 11 0 proc 51 38K 63K 78643K 537 0 subproc 32 2K 2K 78643K 68 0 NFS srvsock 1 0K 0K 78643K 1 0 NFS daemon 1 16K 16K 78643K 1 0 ip_moptions 0 0K 0K 78643K 80 0 in_multi 126 5K 5K 78643K 269 0 ether_multi 1 0K 0K 78643K 25 0 mrt 1 0K 0K 78643K 137 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 304 0 pfkey data 0 0K 0K 78643K 4 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 159 138K 140K 78643K 3597 0 UVM aobj 35 2K 2K 78643K 42 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 ip6_options 0 0K 1K 78643K 164 0 NDP 14 0K 0K 78643K 51 0 temp 142 3860K 3924K 78643K 31775 0 kqueue 3 4K 18K 78643K 63 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 16 0 7 1 0 1 1 0 8 0 rtpcb 80 72 0 70 1 0 1 1 0 8 0 rtentry 112 167 0 131 2 0 2 2 0 8 0 unpcb 120 601 0 593 1 0 1 1 0 8 0 syncache 264 24 0 24 5 5 0 1 0 8 0 tcpqe 32 79 0 79 2 2 0 1 0 8 0 tcpcb 544 389 0 385 1 0 1 1 0 8 0 ipq 40 8 0 8 3 3 0 1 0 8 0 ipqe 40 107 0 107 3 3 0 1 0 8 0 inpcb 280 2894 0 2886 2 1 1 2 0 8 0 rttmr 72 40 0 40 2 2 0 1 0 8 0 nd6 48 24 0 20 1 0 1 1 0 8 0 pkpcb 40 8 0 8 4 4 0 1 0 8 0 ppxss 1128 1 0 1 1 1 0 1 0 8 0 pfstscr 40 4 0 2 1 0 1 1 0 8 0 pfosfp 40 3 0 0 1 0 1 1 0 8 0 pfosfpen 112 4 0 0 1 0 1 1 0 8 0 pfrke_plain 160 8 0 8 1 1 0 1 0 8 0 pfrktable 1344 259 0 253 4 3 1 2 0 8 0 pftag 88 20 0 16 1 0 1 1 0 8 0 pfstitem 24 2 0 0 1 0 1 1 0 8 0 pfstkey 112 4 0 2 1 0 1 1 0 8 0 pfstate 328 2 0 1 1 0 1 1 0 8 0 pfrule 1360 60 0 46 2 0 2 2 0 8 0 art_heap8 4096 2 0 0 2 0 2 2 0 8 0 art_heap4 256 587 0 437 18 7 11 15 0 8 0 art_table 32 589 0 437 2 0 2 2 0 8 0 art_node 16 165 0 134 1 0 1 1 0 8 0 sysvmsgpl 40 58 0 44 1 0 1 1 0 8 0 semapl 112 170 0 160 1 0 1 1 0 8 0 shmpl 112 40 0 8 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 3009 0 1616 88 0 88 88 0 8 0 ffsino 240 3009 0 1616 83 0 83 83 0 8 0 nchpl 144 4845 0 3263 60 0 60 60 0 8 0 rtmask 32 16 0 16 1 1 0 1 0 8 0 uvmvnodes 72 3453 0 0 63 0 63 63 0 8 0 vnodes 208 3453 0 0 182 0 182 182 0 8 0 namei 1024 13518 0 13518 3 2 1 1 0 8 1 vcpupl 1984 11 0 0 2 0 2 2 0 8 0 vmpool 528 16 0 5 1 0 1 1 0 8 0 pfiaddrpl 120 88 0 84 1 0 1 1 0 8 0 scxspl 192 15370 0 15370 3 2 1 1 0 8 1 plimitpl 152 82 0 75 1 0 1 1 0 8 0 sigapl 424 1383 0 1333 6 0 6 6 0 8 0 futexpl 56 24817 0 24817 2 1 1 1 0 8 1 knotepl 112 162 0 143 1 0 1 1 0 8 0 kqueuepl 144 186 0 184 1 0 1 1 0 8 0 pipelkpl 16 267 0 257 1 0 1 1 0 8 0 pipepl 120 534 0 515 2 1 1 2 0 8 0 fdescpl 432 1347 0 1333 2 0 2 2 0 8 0 filepl 120 9150 0 9055 4 0 4 4 0 8 0 lockfpl 104 272 0 271 1 0 1 1 0 8 0 lockfspl 48 105 0 104 1 0 1 1 0 8 0 sessionpl 112 20 0 10 1 0 1 1 0 8 0 pgrppl 48 24 0 14 1 0 1 1 0 8 0 ucredpl 96 988 0 981 1 0 1 1 0 8 0 zombiepl 144 1333 0 1333 2 1 1 1 0 8 1 processpl 920 1383 0 1333 7 0 7 7 0 8 0 procpl 624 2743 0 2685 5 0 5 5 0 8 0 sosppl 128 17 0 17 4 4 0 1 0 8 0 sockpl 400 3584 0 3566 7 4 3 4 0 8 0 mcl64k 65536 1386 0 871 147 82 65 66 0 8 0 mcl16k 16384 8 0 8 3 3 0 1 0 8 0 mcl12k 12288 38 0 38 2 2 0 1 0 8 0 mcl9k 9216 14 0 14 4 4 0 1 0 8 0 mcl8k 8192 39 0 39 1 1 0 1 0 8 0 mcl4k 4096 107 0 107 3 3 0 1 0 8 0 mcl2k2 2112 10 0 10 4 4 0 1 0 8 0 mcl2k 2048 73935 0 73881 17 10 7 13 0 8 0 mtagpl 80 103 0 66 2 1 1 1 0 8 0 mbufpl 256 126775 0 125846 100 36 64 64 0 8 0 bufpl 280 8596 0 3244 383 0 383 383 0 8 0 anonpl 16 158291 0 142897 104 34 70 82 0 107 2 amapchunkpl 152 6668 0 6502 39 32 7 20 0 158 0 amappl16 192 7424 0 6548 80 35 45 57 0 8 0 amappl15 184 804 0 801 1 0 1 1 0 8 0 amappl14 176 38 0 31 1 0 1 1 0 8 0 amappl13 168 40 0 37 1 0 1 1 0 8 0 amappl12 160 20 0 17 2 1 1 1 0 8 0 amappl11 152 304 0 295 1 0 1 1 0 8 0 amappl10 144 318 0 313 1 0 1 1 0 8 0 amappl9 136 361 0 360 1 0 1 1 0 8 0 amappl8 128 412 0 362 2 0 2 2 0 8 0 amappl7 120 119 0 107 1 0 1 1 0 8 0 amappl6 112 282 0 277 1 0 1 1 0 8 0 amappl5 104 1041 0 1028 1 0 1 1 0 8 0 amappl4 96 728 0 700 1 0 1 1 0 8 0 amappl3 88 160 0 153 1 0 1 1 0 8 0 amappl2 80 10375 0 10307 2 0 2 2 0 8 0 amappl1 72 33330 0 32915 23 13 10 17 0 8 0 amappl 80 2994 0 2944 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 41 0 7 1 0 1 1 0 8 0 uaddrrnd 24 1363 0 1338 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 1363 0 1338 1 0 1 1 0 8 0 vmmpekpl 168 10700 0 10663 2 0 2 2 0 8 0 vmmpepl 168 165080 0 163080 167 48 119 122 0 357 26 vmsppl 272 1362 0 1338 2 0 2 2 0 8 0 pdppl 4096 2732 0 2687 9 3 6 7 0 8 0 pvpl 32 450334 0 432237 237 55 182 232 0 265 28 pmappl 200 1362 0 1338 2 0 2 2 0 8 0 extentpl 40 53 0 36 1 0 1 1 0 8 0 phpool 112 496 0 153 11 0 11 11 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(ffffffff823aed46) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8069b5f500,53c,384,2) 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(fffffd805da704b8,9,fffffd8069b5f400,0,0,ffff80001d717010) at tcp_usrreq+0xa54 sosend(fffffd805da704b8,0,ffff80001d71ec98,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d717010,4,ffff80001d71ec98,0,ffff80001d71ed80) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d717010,ffff80001d71ed30,ffff80001d71ed80) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d71ee00) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffe3970, 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(ffffffff823aed46) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8069b5f500,53c,384,2) 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(fffffd805da704b8,9,fffffd8069b5f400,0,0,ffff80001d717010) at tcp_usrreq+0xa54 sosend(fffffd805da704b8,0,ffff80001d71ec98,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d717010,4,ffff80001d71ec98,0,ffff80001d71ed80) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d717010,ffff80001d71ed30,ffff80001d71ed80) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d71ee00) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffe3970, count: -10