panic: m_copym0: short mbuf chain Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND 144942 59818 0 0x2 0 1K syz-executor.1 *241269 55408 0 0x12 0 0 sshd db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff821ed19d) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd806d91f500,2ec,11c,2) at m_copym+0x583 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000a0aaa0) at tcp_output+0x15ba sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd806eb32968,9,fffffd806cca8b00,0,0,ffff800020edeeb0) at tcp_usrreq+0xa55 sosend(fffffd806eb32968,0,ffff800020ecf7c8,0,0,80) at sosend+0x671 sys/kern/uipc_socket.c:549 dofilewritev(ffff800020edeeb0,4,ffff800020ecf7c8,0,ffff800020ecf8b0) at dofilewritev+0x1b6 sys/kern/sys_generic.c:365 sys_write(ffff800020edeeb0,ffff800020ecf860,ffff800020ecf8b0) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff800020ecf930) at syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff800020ecf930) at syscall+0x4a4 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7fffff3590, 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{0}> ddb{0}> set $lines = 0 ddb{0}> set $maxwidth = 0 ddb{0}> show panic m_copym0: short mbuf chain ddb{0}> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff821ed19d) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd806d91f500,2ec,11c,2) at m_copym+0x583 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000a0aaa0) at tcp_output+0x15ba sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd806eb32968,9,fffffd806cca8b00,0,0,ffff800020edeeb0) at tcp_usrreq+0xa55 sosend(fffffd806eb32968,0,ffff800020ecf7c8,0,0,80) at sosend+0x671 sys/kern/uipc_socket.c:549 dofilewritev(ffff800020edeeb0,4,ffff800020ecf7c8,0,ffff800020ecf8b0) at dofilewritev+0x1b6 sys/kern/sys_generic.c:365 sys_write(ffff800020edeeb0,ffff800020ecf860,ffff800020ecf8b0) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff800020ecf930) at syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff800020ecf930) at syscall+0x4a4 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7fffff3590, count: -10 ddb{0}> show registers rdi 0 rsi 0x1 rbp 0xffff800020ecf290 rbx 0xffff800020ecf340 rdx 0x8b rcx 0x2 rax 0x1 r8 0xffffffff81c69d7f kprintf+0x16f r9 0x1 r10 0x2 r11 0x1d46e845c6aa720c r12 0x3000000008 r13 0xffff800020ecf2a0 r14 0x100 r15 0x1 rip 0xffffffff81f40c18 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff800020ecf280 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb{0}> show proc PROC (sshd) pid=241269 stat=onproc flags process=12 proc=0 pri=24, usrpri=50, nice=20 forw=0xffffffffffffffff, list=0xffff800020edec40,0xffff800020edf3a0 process=0xffff800020ec87c8 user=0xffff800020eca000, vmspace=0xfffffd806e9445c8 estcpu=0, cpticks=0, pctcpu=0.1 user=0, sys=0, intr=0 ddb{0}> ps PID TID PPID UID S FLAGS WAIT COMMAND 99474 402619 11264 0 2 0x2 syz-executor.0 11218 475578 0 0 3 0x14200 bored sosplice 85887 67922 0 0 3 0x14200 acct acct 59818 144942 11264 0 7 0x2 syz-executor.1 11264 79282 2721 0 3 0x82 thrsleep syz-fuzzer 11264 71105 2721 0 3 0x4000082 nanosleep syz-fuzzer 11264 26279 2721 0 3 0x4000082 thrsleep syz-fuzzer 11264 222010 2721 0 3 0x4000082 thrsleep syz-fuzzer 11264 182487 2721 0 3 0x4000082 kqread syz-fuzzer 11264 250214 2721 0 3 0x4000082 thrsleep syz-fuzzer 11264 272872 2721 0 3 0x4000082 thrsleep syz-fuzzer 11264 84050 2721 0 2 0x4000002 syz-fuzzer 11264 185684 2721 0 3 0x4000082 thrsleep syz-fuzzer 11264 353724 2721 0 3 0x4000082 thrsleep syz-fuzzer 2721 341007 55408 0 3 0x10008a pause ksh *55408 241269 62139 0 7 0x12 sshd 69165 83144 1 0 3 0x100083 ttyin getty 62139 145767 1 0 3 0x80 select sshd 14553 432505 41216 74 3 0x100092 bpf pflogd 41216 493600 1 0 3 0x80 netio pflogd 98530 80064 80531 73 3 0x100090 kqread syslogd 80531 193169 1 0 3 0x100082 netio syslogd 79339 216423 1 77 3 0x100090 poll dhclient 54411 511361 1 0 3 0x80 poll dhclient 76538 155313 0 0 3 0x14200 bored smr 60143 383243 0 0 3 0x14200 pgzero zerothread 59099 140058 0 0 3 0x14200 aiodoned aiodoned 55452 353679 0 0 3 0x14200 syncer update 43324 405738 0 0 3 0x14200 cleaner cleaner 83544 141557 0 0 3 0x14200 reaper reaper 19193 498513 0 0 3 0x14200 pgdaemon pagedaemon 47929 287375 0 0 3 0x14200 bored crynlk 42651 504939 0 0 3 0x14200 bored crypto 65175 164952 0 0 3 0x40014200 acpi0 acpi0 39337 140350 0 0 3 0x40014200 idle1 78662 263316 0 0 3 0x14200 bored softnet 78165 407600 0 0 3 0x14200 bored systqmp 92732 124781 0 0 3 0x14200 bored systq 39845 37083 0 0 3 0x40014200 bored softclock 70615 189813 0 0 3 0x40014200 idle0 1 501298 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{0}> show all locks Process 55408 (sshd) thread 0xffff800020edeeb0 (241269) exclusive rwlock netlock r = 0 (0xffffffff824e45e8) #0 witness_lock+0x4c7 stacktrace_save sys/sys/stacktrace.h:36 [inline] #0 witness_lock+0x4c7 sys/kern/subr_witness.c:1164 #1 solock+0x5a sys/kern/uipc_socket2.c:282 #2 sosend+0x559 sys/kern/uipc_socket.c:537 #3 dofilewritev+0x1b6 sys/kern/sys_generic.c:365 #4 sys_write+0x83 sys/kern/sys_generic.c:285 #5 syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:102 [inline] #5 syscall+0x4a4 sys/arch/amd64/amd64/trap.c:570 #6 Xsyscall+0x128 ddb{0}> show malloc Type InUse MemUse HighUse Limit Requests Type Lim devbuf 9515 6413K 6790K 78643K 10926 0 pcb 13 8K 8K 78643K 95 0 rtable 90 4K 6K 78643K 369 0 ifaddr 63 12K 14K 78643K 128 0 counters 41 33K 34K 78643K 57 0 ioctlops 0 0K 4K 78643K 1495 0 iov 0 0K 28K 78643K 39 0 mount 1 1K 1K 78643K 1 0 vnodes 1219 77K 77K 78643K 1355 0 UFS quota 1 32K 32K 78643K 1 0 UFS mount 5 36K 36K 78643K 5 0 shm 2 1K 5K 78643K 5 0 VM map 2 1K 1K 78643K 2 0 sem 12 0K 0K 78643K 55 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1824 197K 290K 78643K 13058 0 file desc 4 9K 25K 78643K 308 0 proc 60 63K 95K 78643K 492 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 44 0 in_multi 31 2K 2K 78643K 97 0 ether_multi 1 0K 0K 78643K 14 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 49 228K 228K 78643K 49 0 exec 0 0K 1K 78643K 248 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 126 39K 48K 78643K 1982 0 UVM aobj 12 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 67 0 NDP 11 0K 0K 78643K 25 0 temp 93 3035K 3103K 78643K 4608 0 kqueue 3 4K 8K 78643K 17 0 SYN cache 2 16K 16K 78643K 2 0 ddb{0}> show all pools Name Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle arp 64 12 0 8 1 0 1 1 0 8 0 plcache 128 20 0 0 1 0 1 1 0 8 0 rtpcb 80 25 0 23 1 0 1 1 0 8 0 rtentry 112 73 0 40 2 0 2 2 0 8 1 unpcb 120 137 0 127 1 0 1 1 0 8 0 syncache 264 6 0 6 2 1 1 1 0 8 1 tcpcb 544 140 0 136 1 0 1 1 0 8 0 inpcb 280 440 0 433 3 1 2 2 0 8 1 rttmr 72 1 0 1 1 1 0 1 0 8 0 ip6q 72 1 0 1 1 1 0 1 0 8 0 ip6af 40 3 0 3 1 1 0 1 0 8 0 nd6 48 9 0 6 1 0 1 1 0 8 0 pkpcb 40 2 0 2 1 0 1 1 0 8 1 ppxss 1128 2 0 2 1 0 1 1 0 8 1 pfosfp 40 846 0 423 5 0 5 5 0 8 0 pfosfpen 112 1428 0 714 21 0 21 21 0 8 0 pfrktable 1344 10 0 8 2 1 1 1 0 8 0 pfstitem 24 33 0 4 1 0 1 1 0 8 0 pfstkey 112 33 0 4 1 0 1 1 0 8 0 pfstate 328 33 0 4 3 0 3 3 0 8 0 pfrule 1360 24 0 18 2 1 1 2 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 257 0 105 13 0 13 13 0 8 3 art_table 32 258 0 105 2 0 2 2 0 8 0 art_node 16 72 0 42 1 0 1 1 0 8 0 sysvmsgpl 40 2 0 0 1 0 1 1 0 8 0 semupl 112 3 0 3 1 1 0 1 0 8 0 semapl 112 51 0 41 1 0 1 1 0 8 0 shmpl 112 10 0 0 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 1786 0 381 89 0 89 89 0 8 0 ffsino 272 1786 0 381 95 0 95 95 0 8 0 nchpl 144 2523 0 929 60 0 60 60 0 8 0 uvmvnodes 72 1919 0 0 35 0 35 35 0 8 0 vnodes 208 1919 0 0 101 0 101 101 0 8 0 namei 1024 6945 0 6944 1 0 1 1 0 8 0 percpumem 16 39 0 8 1 0 1 1 0 8 0 vcpupl 1984 2 0 0 1 0 1 1 0 8 0 vmpool 560 7 0 5 1 0 1 1 0 8 0 pfiaddrpl 120 3 0 2 2 1 1 1 0 8 0 scxspl 192 6317 0 6317 8 7 1 7 0 8 1 plimitpl 152 42 0 34 1 0 1 1 0 8 0 sigapl 424 522 0 490 4 0 4 4 0 8 0 futexpl 56 4318 0 4318 1 0 1 1 0 8 1 knotepl 112 87 0 68 1 0 1 1 0 8 0 kqueuepl 144 55 0 53 1 0 1 1 0 8 0 pipelkpl 48 133 0 123 1 0 1 1 0 8 0 pipepl 120 266 0 247 2 0 2 2 0 8 1 fdescpl 496 505 0 490 3 0 3 3 0 8 0 filepl 152 3247 0 3147 7 0 7 7 0 8 3 lockfpl 104 66 0 65 1 0 1 1 0 8 0 lockfspl 48 25 0 24 1 0 1 1 0 8 0 sessionpl 112 19 0 8 1 0 1 1 0 8 0 pgrppl 48 21 0 10 1 0 1 1 0 8 0 ucredpl 96 318 0 309 1 0 1 1 0 8 0 zombiepl 144 490 0 490 1 0 1 1 0 8 1 processpl 984 522 0 490 5 0 5 5 0 8 0 procpl 624 1152 0 1111 4 0 4 4 0 8 0 srpgc 64 2 0 2 1 0 1 1 0 8 1 sosppl 128 7 0 7 1 0 1 1 0 8 1 sockpl 400 604 0 585 4 0 4 4 0 8 2 mcl64k 65536 7 0 0 1 0 1 1 0 8 0 mcl12k 12288 4 0 0 1 0 1 1 0 8 0 mcl9k 9216 2 0 0 1 0 1 1 0 8 0 mcl8k 8192 3 0 0 1 0 1 1 0 8 0 mcl4k 4096 7 0 0 1 0 1 1 0 8 0 mcl2k2 2112 1 0 0 1 0 1 1 0 8 0 mcl2k 2048 166 0 0 20 0 20 20 0 8 0 mtagpl 80 16 0 0 1 0 1 1 0 8 0 mbufpl 256 179 0 0 11 0 11 11 0 8 0 bufpl 280 3732 0 135 257 0 257 257 0 8 0 anonpl 16 63001 0 47832 75 1 74 74 0 124 8 amapchunkpl 152 2917 0 2771 13 2 11 11 0 158 4 amappl16 192 2078 0 1214 44 0 44 44 0 8 0 amappl15 184 111 0 111 2 1 1 1 0 8 1 amappl14 176 36 0 29 1 0 1 1 0 8 0 amappl13 168 35 0 32 1 0 1 1 0 8 0 amappl12 160 6 0 4 2 1 1 1 0 8 0 amappl11 152 59 0 44 1 0 1 1 0 8 0 amappl10 144 152 0 145 1 0 1 1 0 8 0 amappl9 136 341 0 338 1 0 1 1 0 8 0 amappl8 128 405 0 368 2 0 2 2 0 8 0 amappl7 120 125 0 113 1 0 1 1 0 8 0 amappl6 112 29 0 22 1 0 1 1 0 8 0 amappl5 104 529 0 514 1 0 1 1 0 8 0 amappl4 96 509 0 480 1 0 1 1 0 8 0 amappl3 88 114 0 107 1 0 1 1 0 8 0 amappl2 80 3130 0 3069 2 0 2 2 0 8 0 amappl1 72 21621 0 21197 24 14 10 18 0 8 0 amappl 80 1421 0 1378 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 11 0 0 1 0 1 1 0 8 0 uaddrrnd 24 512 0 495 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 512 0 495 1 0 1 1 0 8 0 vmmpekpl 168 8025 0 7988 2 0 2 2 0 8 0 vmmpepl 168 68593 0 66679 144 21 123 123 0 357 34 vmsppl 368 511 0 495 2 0 2 2 0 8 0 pdppl 4096 1032 0 992 6 0 6 6 0 8 0 pvpl 32 200653 0 182422 176 0 176 176 0 265 18 pmappl 232 511 0 495 2 0 2 2 0 8 1 extentpl 40 53 0 36 1 0 1 1 0 8 0 phpool 112 257 0 3 8 0 8 8 0 8 0 ddb{0}> machine ddbcpu 0 Invalid cpu 0 ddb{0}> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff821ed19d) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd806d91f500,2ec,11c,2) at m_copym+0x583 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000a0aaa0) at tcp_output+0x15ba sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd806eb32968,9,fffffd806cca8b00,0,0,ffff800020edeeb0) at tcp_usrreq+0xa55 sosend(fffffd806eb32968,0,ffff800020ecf7c8,0,0,80) at sosend+0x671 sys/kern/uipc_socket.c:549 dofilewritev(ffff800020edeeb0,4,ffff800020ecf7c8,0,ffff800020ecf8b0) at dofilewritev+0x1b6 sys/kern/sys_generic.c:365 sys_write(ffff800020edeeb0,ffff800020ecf860,ffff800020ecf8b0) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff800020ecf930) at syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff800020ecf930) at syscall+0x4a4 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7fffff3590, count: -10 ddb{0}> machine ddbcpu 1