panic: syn_cache_insert: cacheoverflow: impossible Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *411838 40245 0 0x14000 0x200 0 softnet db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff823c292d) at panic+0x15c sys/kern/subr_prf.c:207 syn_cache_insert(fffffd80666a2e88,ffff800000ac0760) at syn_cache_insert+0x944 sys/netinet/tcp_input.c:3235 syn_cache_add(ffff80001d677be8,ffff80001d677b98,fffffd8053c865c4,14,fffffd806b34faf0,fffffd8053c86500) at syn_cache_add+0x66b tcp_input(ffff80001d677ee8,ffff80001d677ef4,6,2) at tcp_input+0x37d8 sys/netinet/tcp_input.c:830 ip_deliver(ffff80001d677ee8,ffff80001d677ef4,6,2) at ip_deliver+0x2e3 sys/netinet/ip_input.c:668 ip_ours(ffff80001d677ee8,ffff80001d677ef4,2,0) at ip_ours+0x4fe sys/netinet/ip_input.c:563 ip_input_if(ffff80001d677ee8,ffff80001d677ef4,4,0,ffff800000677800) at ip_input_if+0x571 ipv4_input(ffff800000677800,fffffd8053c86500) at ipv4_input+0x48 sys/netinet/ip_input.c:215 if_input_local(ffff800000677800,fffffd8053c86500,2) at if_input_local+0xf9 sys/net/if.c:775 loinput(ffff800000677800,fffffd8053c86500,0) at loinput+0x4f sys/net/if_loop.c:239 if_input_process(ffff800000677800,ffff80001d678038) at if_input_process+0xf8 if_ih_input sys/net/if.c:908 [inline] if_input_process(ffff800000677800,ffff80001d678038) at if_input_process+0xf8 sys/net/if.c:942 ifiq_process(ffff800000677bb8) at ifiq_process+0x80 sys/net/ifq.c:646 taskq_thread(ffff80000002b080) at taskq_thread+0x92 sys/kern/kern_task.c:438 end trace frame: 0x0, count: 1 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 syn_cache_insert: cacheoverflow: impossible ddb> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff823c292d) at panic+0x15c sys/kern/subr_prf.c:207 syn_cache_insert(fffffd80666a2e88,ffff800000ac0760) at syn_cache_insert+0x944 sys/netinet/tcp_input.c:3235 syn_cache_add(ffff80001d677be8,ffff80001d677b98,fffffd8053c865c4,14,fffffd806b34faf0,fffffd8053c86500) at syn_cache_add+0x66b tcp_input(ffff80001d677ee8,ffff80001d677ef4,6,2) at tcp_input+0x37d8 sys/netinet/tcp_input.c:830 ip_deliver(ffff80001d677ee8,ffff80001d677ef4,6,2) at ip_deliver+0x2e3 sys/netinet/ip_input.c:668 ip_ours(ffff80001d677ee8,ffff80001d677ef4,2,0) at ip_ours+0x4fe sys/netinet/ip_input.c:563 ip_input_if(ffff80001d677ee8,ffff80001d677ef4,4,0,ffff800000677800) at ip_input_if+0x571 ipv4_input(ffff800000677800,fffffd8053c86500) at ipv4_input+0x48 sys/netinet/ip_input.c:215 if_input_local(ffff800000677800,fffffd8053c86500,2) at if_input_local+0xf9 sys/net/if.c:775 loinput(ffff800000677800,fffffd8053c86500,0) at loinput+0x4f sys/net/if_loop.c:239 if_input_process(ffff800000677800,ffff80001d678038) at if_input_process+0xf8 if_ih_input sys/net/if.c:908 [inline] if_input_process(ffff800000677800,ffff80001d678038) at if_input_process+0xf8 sys/net/if.c:942 ifiq_process(ffff800000677bb8) at ifiq_process+0x80 sys/net/ifq.c:646 taskq_thread(ffff80000002b080) at taskq_thread+0x92 sys/kern/kern_task.c:438 end trace frame: 0x0, count: -14 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff80001d677760 rbx 0xffff80001d677810 rdx 0x2 rcx 0 rax 0x1 r8 0xffffffff81203d6f kprintf+0x15f r9 0x1 r10 0x2 r11 0x2c8663108676c2e0 r12 0x3000000008 r13 0xffff80001d677770 r14 0x100 r15 0x1 rip 0xffffffff81869548 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff80001d677750 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (softnet) pid=411838 stat=onproc flags process=14000 proc=200 pri=32, usrpri=50, nice=20 forw=0xffffffffffffffff, list=0xffff80001d651270,0xffff80001d6519d0 process=0xffff8000ffffe398 user=0xffff80001d673000, vmspace=0xffffffff827ea8f8 estcpu=0, cpticks=0, pctcpu=0.0 user=0, sys=0, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 99442 501644 93561 0 2 0 syz-executor.1 99442 457952 93561 0 3 0x4000080 netcon2 syz-executor.1 66869 469584 0 0 3 0x14280 nfsidl nfsio 28001 36330 0 0 3 0x14280 nfsidl nfsio 57780 104509 0 0 3 0x14280 nfsidl nfsio 8550 480601 0 0 3 0x14280 nfsidl nfsio 81929 245627 0 0 3 0x14280 nfsidl nfsio 29316 349403 0 0 3 0x14280 nfsidl nfsio 87777 440489 0 0 3 0x14280 nfsidl nfsio 40130 201115 0 0 3 0x14280 nfsidl nfsio 46445 210425 0 0 3 0x14280 nfsidl nfsio 45083 73953 0 0 3 0x14280 nfsidl nfsio 56918 431173 0 0 3 0x14280 nfsidl nfsio 911 303825 0 0 3 0x14280 nfsidl nfsio 34172 253576 0 0 3 0x14280 nfsidl nfsio 20441 169567 0 0 3 0x14280 nfsidl nfsio 90567 142473 0 0 3 0x14280 nfsidl nfsio 77683 177287 0 0 3 0x14280 nfsidl nfsio 22425 13951 0 0 3 0x14280 nfsidl nfsio 74519 316508 0 0 3 0x14280 nfsidl nfsio 16521 39729 0 0 3 0x14280 nfsidl nfsio 67005 362227 0 0 3 0x14280 nfsidl nfsio 21813 265012 0 0 3 0x14200 bored sosplice 93561 380434 47725 0 3 0x82 nanosleep syz-executor.1 9249 154273 47725 0 2 0x2 syz-executor.0 47725 113226 45309 0 3 0x82 thrsleep syz-fuzzer 47725 396582 45309 0 3 0x4000082 nanosleep syz-fuzzer 47725 126550 45309 0 3 0x4000082 thrsleep syz-fuzzer 47725 207735 45309 0 3 0x4000082 thrsleep syz-fuzzer 47725 400961 45309 0 3 0x4000082 thrsleep syz-fuzzer 47725 105118 45309 0 3 0x4000082 kqread syz-fuzzer 47725 23511 45309 0 3 0x4000082 thrsleep syz-fuzzer 47725 291101 45309 0 3 0x4000082 thrsleep syz-fuzzer 45309 174543 54515 0 3 0x10008a pause ksh 54515 68686 18064 0 3 0x92 select sshd 27441 497476 1 0 3 0x100083 ttyin getty 18064 222209 1 0 3 0x80 select sshd 19089 57576 50812 73 3 0x100090 kqread syslogd 50812 248986 1 0 3 0x100082 netio syslogd 65383 392948 1 77 3 0x100090 poll dhclient 89271 373953 1 0 3 0x80 poll dhclient 7861 217873 0 0 3 0x14200 bored smr 78820 265648 0 0 2 0x14200 zerothread 30536 474501 0 0 3 0x14200 aiodoned aiodoned 58056 485947 0 0 3 0x14200 syncer update 80933 249416 0 0 3 0x14200 cleaner cleaner 55094 429461 0 0 3 0x14200 reaper reaper 731 183725 0 0 3 0x14200 pgdaemon pagedaemon 1194 346931 0 0 3 0x14200 bored crynlk 95144 437506 0 0 3 0x14200 bored crypto 18504 404311 0 0 3 0x40014200 acpi0 acpi0 *40245 411838 0 0 7 0x14200 softnet 72494 238055 0 0 3 0x14200 bored systqmp 98887 521514 0 0 3 0x14200 bored systq 77044 437503 0 0 3 0x40014200 bored softclock 33949 359886 0 0 3 0x40014200 idle0 1 316475 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 9514 6358K 7077K 78643K 13066 0 pcb 13 8K 8K 78643K 173 0 rtable 126 18K 22K 78643K 646 0 ifaddr 94 19K 20K 78643K 262 0 sysctl 2 0K 0K 78643K 2 0 counters 21 16K 16K 78643K 40 0 ioctlops 0 0K 4K 78643K 114 0 iov 0 0K 14K 78643K 356 0 mount 1 1K 1K 78643K 1 0 vnodes 1218 77K 77K 78643K 1860 0 UFS quota 1 32K 32K 78643K 1 0 UFS mount 5 36K 36K 78643K 5 0 shm 2 1K 5K 78643K 8 0 VM map 2 0K 0K 78643K 2 0 sem 12 1K 1K 78643K 50 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1809 195K 288K 78643K 12938 0 file desc 5 13K 25K 78643K 661 0 sigio 0 0K 0K 78643K 4 0 proc 49 38K 63K 78643K 416 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 75 0 in_multi 66 3K 3K 78643K 159 0 ether_multi 1 0K 0K 78643K 28 0 mrt 0 0K 0K 78643K 11 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 237 0 pfkey data 0 0K 0K 78643K 2 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 141 104K 105K 78643K 2388 0 UVM aobj 36 2K 2K 78643K 39 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 ip6_options 2 0K 0K 78643K 167 0 NDP 13 0K 0K 78643K 36 0 temp 138 3860K 3934K 78643K 15900 0 kqueue 3 4K 18K 78643K 58 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 1 1 0 1 1 0 8 0 rtpcb 80 79 0 77 1 0 1 1 0 8 0 rtentry 112 65 0 29 2 0 2 2 0 8 0 unpcb 120 325 0 317 1 0 1 1 0 8 0 syncache 264 10 0 9 4 3 1 1 0 8 0 sackhl 24 1 0 1 1 1 0 1 0 8 0 tcpqe 32 55 0 55 1 1 0 1 0 8 0 tcpcb 544 374 0 366 3 2 1 2 0 8 0 ipq 40 3 0 3 2 2 0 1 0 8 0 ipqe 40 8 0 8 2 2 0 1 0 8 0 inpcb 280 918 0 907 6 4 2 3 0 8 1 rttmr 72 5 0 5 3 2 1 1 0 8 1 nd6 48 9 0 6 1 0 1 1 0 8 0 pkpcb 40 2 0 2 1 1 0 1 0 8 0 swfcl 56 1 0 0 1 0 1 1 0 8 0 ppxss 1128 1 0 1 1 1 0 1 0 8 0 pfstscr 40 2 0 0 1 0 1 1 0 8 0 pfosfp 40 1 0 0 1 0 1 1 0 8 0 pfosfpen 112 1 0 0 1 0 1 1 0 8 0 pfrktable 1344 105 0 91 2 0 2 2 0 8 0 pftag 88 16 0 10 1 0 1 1 0 8 0 pfstitem 24 3 0 0 1 0 1 1 0 8 0 pfstkey 112 3 0 0 1 0 1 1 0 8 0 pfstate 328 2 0 0 1 0 1 1 0 8 0 pfrule 1360 41 0 19 2 0 2 2 0 8 0 art_heap8 4096 2 0 0 2 0 2 2 0 8 0 art_heap4 256 261 0 110 13 1 12 12 0 8 1 art_table 32 263 0 110 2 0 2 2 0 8 0 art_node 16 64 0 33 1 0 1 1 0 8 0 sysvmsgpl 40 55 0 20 1 0 1 1 0 8 0 semupl 112 2 0 2 2 2 0 1 0 8 0 semapl 112 45 0 35 1 0 1 1 0 8 0 shmpl 112 37 0 3 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 2343 0 950 88 0 88 88 0 8 0 ffsino 240 2343 0 950 83 0 83 83 0 8 0 nchpl 144 3615 0 2025 60 0 60 60 0 8 0 uvmvnodes 72 2916 0 0 54 0 54 54 0 8 0 vnodes 208 2916 0 0 154 0 154 154 0 8 0 namei 1024 10194 0 10194 2 1 1 1 0 8 1 vcpupl 1984 9 0 0 2 0 2 2 0 8 0 vmpool 528 11 0 2 1 0 1 1 0 8 0 pfiaddrpl 120 36 0 24 1 0 1 1 0 8 0 scsiplug 64 1 0 1 1 0 1 1 0 8 1 scxspl 192 9937 0 9937 1 0 1 1 0 8 1 plimitpl 152 76 0 69 1 0 1 1 0 8 0 sigapl 424 868 0 819 6 0 6 6 0 8 0 futexpl 56 15213 0 15213 2 1 1 1 0 8 1 knotepl 112 131 0 112 1 0 1 1 0 8 0 kqueuepl 144 130 0 125 1 0 1 1 0 8 0 pipepl 272 169 0 159 2 1 1 2 0 8 0 fdescpl 432 833 0 819 2 0 2 2 0 8 0 filepl 120 5619 0 5522 4 0 4 4 0 8 1 lockfpl 104 857 0 856 1 0 1 1 0 8 0 lockfspl 48 396 0 395 1 0 1 1 0 8 0 sessionpl 112 17 0 7 1 0 1 1 0 8 0 pgrppl 48 31 0 21 1 0 1 1 0 8 0 ucredpl 96 651 0 644 1 0 1 1 0 8 0 zombiepl 144 819 0 819 1 0 1 1 0 8 1 processpl 920 868 0 819 7 0 7 7 0 8 0 procpl 624 1665 0 1608 5 0 5 5 0 8 0 sosppl 128 10 0 10 3 2 1 1 0 8 1 sockpl 400 1329 0 1308 8 4 4 5 0 8 1 mcl64k 65536 63 0 63 3 2 1 1 0 8 1 mcl16k 16384 4 0 4 1 1 0 1 0 8 0 mcl12k 12288 18 0 18 4 3 1 1 0 8 1 mcl9k 9216 12 0 12 2 2 0 1 0 8 0 mcl8k 8192 25 0 25 3 2 1 1 0 8 1 mcl4k 4096 70 0 70 3 2 1 1 0 8 1 mcl2k2 2112 5 0 5 2 2 0 1 0 8 0 mcl2k 2048 77329 0 77274 17 9 8 13 0 8 0 mtagpl 80 319 0 24 8 1 7 7 0 8 0 mbufpl 256 127960 0 127250 50 4 46 46 0 8 0 bufpl 280 4396 0 128 305 0 305 305 0 8 0 anonpl 16 80330 0 64577 73 3 70 70 0 107 3 amapchunkpl 152 3189 0 3030 8 0 8 8 0 158 0 amappl16 192 3619 0 2727 52 4 48 48 0 8 3 amappl15 184 1 0 0 1 0 1 1 0 8 0 amappl14 176 23 0 19 1 0 1 1 0 8 0 amappl13 168 952 0 945 1 0 1 1 0 8 0 amappl12 160 5 0 5 1 1 0 1 0 8 0 amappl11 152 45 0 35 1 0 1 1 0 8 0 amappl10 144 24 0 18 1 0 1 1 0 8 0 amappl9 136 355 0 354 1 0 1 1 0 8 0 amappl8 128 329 0 291 2 0 2 2 0 8 0 amappl7 120 107 0 96 1 0 1 1 0 8 0 amappl6 112 27 0 21 1 0 1 1 0 8 0 amappl5 104 513 0 502 1 0 1 1 0 8 0 amappl4 96 1057 0 1026 1 0 1 1 0 8 0 amappl3 88 427 0 420 1 0 1 1 0 8 0 amappl2 80 5875 0 5809 2 0 2 2 0 8 0 amappl1 72 23454 0 23040 24 15 9 17 0 8 0 amappl 80 1883 0 1832 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 38 0 3 1 0 1 1 0 8 0 uaddrrnd 24 844 0 821 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 844 0 821 1 0 1 1 0 8 0 vmmpekpl 168 8808 0 8777 2 0 2 2 0 8 0 vmmpepl 168 102635 0 100634 126 31 95 115 0 357 4 vmsppl 272 843 0 821 2 0 2 2 0 8 0 pdppl 4096 1694 0 1651 8 2 6 6 0 8 0 pvpl 32 251627 0 232778 182 12 170 170 0 265 12 pmappl 200 843 0 821 2 0 2 2 0 8 0 extentpl 40 53 0 36 1 0 1 1 0 8 0 phpool 112 300 0 33 8 0 8 8 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(ffffffff823c292d) at panic+0x15c sys/kern/subr_prf.c:207 syn_cache_insert(fffffd80666a2e88,ffff800000ac0760) at syn_cache_insert+0x944 sys/netinet/tcp_input.c:3235 syn_cache_add(ffff80001d677be8,ffff80001d677b98,fffffd8053c865c4,14,fffffd806b34faf0,fffffd8053c86500) at syn_cache_add+0x66b tcp_input(ffff80001d677ee8,ffff80001d677ef4,6,2) at tcp_input+0x37d8 sys/netinet/tcp_input.c:830 ip_deliver(ffff80001d677ee8,ffff80001d677ef4,6,2) at ip_deliver+0x2e3 sys/netinet/ip_input.c:668 ip_ours(ffff80001d677ee8,ffff80001d677ef4,2,0) at ip_ours+0x4fe sys/netinet/ip_input.c:563 ip_input_if(ffff80001d677ee8,ffff80001d677ef4,4,0,ffff800000677800) at ip_input_if+0x571 ipv4_input(ffff800000677800,fffffd8053c86500) at ipv4_input+0x48 sys/netinet/ip_input.c:215 if_input_local(ffff800000677800,fffffd8053c86500,2) at if_input_local+0xf9 sys/net/if.c:775 loinput(ffff800000677800,fffffd8053c86500,0) at loinput+0x4f sys/net/if_loop.c:239 if_input_process(ffff800000677800,ffff80001d678038) at if_input_process+0xf8 if_ih_input sys/net/if.c:908 [inline] if_input_process(ffff800000677800,ffff80001d678038) at if_input_process+0xf8 sys/net/if.c:942 ifiq_process(ffff800000677bb8) at ifiq_process+0x80 sys/net/ifq.c:646 taskq_thread(ffff80000002b080) at taskq_thread+0x92 sys/kern/kern_task.c:438 end trace frame: 0x0, count: -14 ddb> machine ddbcpu 1 No such command ddb> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff823c292d) at panic+0x15c sys/kern/subr_prf.c:207 syn_cache_insert(fffffd80666a2e88,ffff800000ac0760) at syn_cache_insert+0x944 sys/netinet/tcp_input.c:3235 syn_cache_add(ffff80001d677be8,ffff80001d677b98,fffffd8053c865c4,14,fffffd806b34faf0,fffffd8053c86500) at syn_cache_add+0x66b tcp_input(ffff80001d677ee8,ffff80001d677ef4,6,2) at tcp_input+0x37d8 sys/netinet/tcp_input.c:830 ip_deliver(ffff80001d677ee8,ffff80001d677ef4,6,2) at ip_deliver+0x2e3 sys/netinet/ip_input.c:668 ip_ours(ffff80001d677ee8,ffff80001d677ef4,2,0) at ip_ours+0x4fe sys/netinet/ip_input.c:563 ip_input_if(ffff80001d677ee8,ffff80001d677ef4,4,0,ffff800000677800) at ip_input_if+0x571 ipv4_input(ffff800000677800,fffffd8053c86500) at ipv4_input+0x48 sys/netinet/ip_input.c:215 if_input_local(ffff800000677800,fffffd8053c86500,2) at if_input_local+0xf9 sys/net/if.c:775 loinput(ffff800000677800,fffffd8053c86500,0) at loinput+0x4f sys/net/if_loop.c:239 if_input_process(ffff800000677800,ffff80001d678038) at if_input_process+0xf8 if_ih_input sys/net/if.c:908 [inline] if_input_process(ffff800000677800,ffff80001d678038) at if_input_process+0xf8 sys/net/if.c:942 ifiq_process(ffff800000677bb8) at ifiq_process+0x80 sys/net/ifq.c:646 taskq_thread(ffff80000002b080) at taskq_thread+0x92 sys/kern/kern_task.c:438 end trace frame: 0x0, count: -14