panic: syn_cache_insert: cacheoverflow: impossible Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *210285 64358 0 0x14000 0x200 0 softnet db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff821dfb20) at panic+0x15c sys/kern/subr_prf.c:207 syn_cache_insert(fffffd805790ce78,ffff8000009f4ee0) at syn_cache_insert+0x944 sys/netinet/tcp_input.c:3235 syn_cache_add(ffff80001d6f7b88,ffff80001d6f7b38,fffffd8005db0868,28,fffffd806a8d8960,fffffd80578fba00) at syn_cache_add+0x66b tcp_input(ffff80001d6f7eb8,ffff80001d6f7ec4,6,18) at tcp_input+0x37d8 sys/netinet/tcp_input.c:830 ip_deliver(ffff80001d6f7eb8,ffff80001d6f7ec4,6,18) at ip_deliver+0x2e3 sys/netinet/ip_input.c:668 ip6_input_if(ffff80001d6f7eb8,ffff80001d6f7ec4,29,0,ffff800000677800) at ip6_input_if+0x1526 ip6_ours sys/netinet6/ip6_input.c:538 [inline] ip6_input_if(ffff80001d6f7eb8,ffff80001d6f7ec4,29,0,ffff800000677800) at ip6_input_if+0x1526 sys/netinet6/ip6_input.c:471 ipv6_input(ffff800000677800,fffffd80578fba00) at ipv6_input+0x48 sys/netinet6/ip6_input.c:171 if_input_local(ffff800000677800,fffffd80578fba00,18) at if_input_local+0x121 sys/net/if.c:779 loinput(ffff800000677800,fffffd80578fba00,0) at loinput+0x4f sys/net/if_loop.c:239 if_input_process(ffff800000677800,ffff80001d6f8008) at if_input_process+0xf8 if_ih_input sys/net/if.c:908 [inline] if_input_process(ffff800000677800,ffff80001d6f8008) at if_input_process+0xf8 sys/net/if.c:942 ifiq_process(ffff800000677bb8) at ifiq_process+0x80 sys/net/ifq.c:646 taskq_thread(ffff8000000290c0) at taskq_thread+0x52 sys/kern/kern_task.c:370 end trace frame: 0x0, count: 2 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(ffffffff821dfb20) at panic+0x15c sys/kern/subr_prf.c:207 syn_cache_insert(fffffd805790ce78,ffff8000009f4ee0) at syn_cache_insert+0x944 sys/netinet/tcp_input.c:3235 syn_cache_add(ffff80001d6f7b88,ffff80001d6f7b38,fffffd8005db0868,28,fffffd806a8d8960,fffffd80578fba00) at syn_cache_add+0x66b tcp_input(ffff80001d6f7eb8,ffff80001d6f7ec4,6,18) at tcp_input+0x37d8 sys/netinet/tcp_input.c:830 ip_deliver(ffff80001d6f7eb8,ffff80001d6f7ec4,6,18) at ip_deliver+0x2e3 sys/netinet/ip_input.c:668 ip6_input_if(ffff80001d6f7eb8,ffff80001d6f7ec4,29,0,ffff800000677800) at ip6_input_if+0x1526 ip6_ours sys/netinet6/ip6_input.c:538 [inline] ip6_input_if(ffff80001d6f7eb8,ffff80001d6f7ec4,29,0,ffff800000677800) at ip6_input_if+0x1526 sys/netinet6/ip6_input.c:471 ipv6_input(ffff800000677800,fffffd80578fba00) at ipv6_input+0x48 sys/netinet6/ip6_input.c:171 if_input_local(ffff800000677800,fffffd80578fba00,18) at if_input_local+0x121 sys/net/if.c:779 loinput(ffff800000677800,fffffd80578fba00,0) at loinput+0x4f sys/net/if_loop.c:239 if_input_process(ffff800000677800,ffff80001d6f8008) at if_input_process+0xf8 if_ih_input sys/net/if.c:908 [inline] if_input_process(ffff800000677800,ffff80001d6f8008) at if_input_process+0xf8 sys/net/if.c:942 ifiq_process(ffff800000677bb8) at ifiq_process+0x80 sys/net/ifq.c:646 taskq_thread(ffff8000000290c0) at taskq_thread+0x52 sys/kern/kern_task.c:370 end trace frame: 0x0, count: -13 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff80001d6f7700 rbx 0xffff80001d6f77b0 rdx 0x2 rcx 0 rax 0x1 r8 0xffffffff8182317f kprintf+0x15f r9 0x1 r10 0x2 r11 0xcc044fe6df72907b r12 0x3000000008 r13 0xffff80001d6f7710 r14 0x100 r15 0x1 rip 0xffffffff8186b358 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff80001d6f76f0 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (softnet) pid=210285 stat=onproc flags process=14000 proc=200 pri=32, usrpri=50, nice=20 forw=0xffffffffffffffff, list=0xffff80001d6d1000,0xffff80001d6d14f0 process=0xffff8000ffffee60 user=0xffff80001d6f3000, vmspace=0xffffffff825e1230 estcpu=0, cpticks=1, pctcpu=0.60 user=0, sys=1, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 33276 311626 68827 0 2 0 syz-executor.1 33276 311983 68827 0 3 0x4000080 netcon2 syz-executor.1 57357 339876 93190 0 2 0x2 syz-executor.0 68827 161835 93190 0 2 0x482 syz-executor.1 93190 223117 18662 0 3 0x82 kqread syz-fuzzer 93190 333857 18662 0 3 0x4000082 nanosleep syz-fuzzer 93190 349579 18662 0 3 0x4000082 thrsleep syz-fuzzer 93190 54934 18662 0 3 0x4000082 thrsleep syz-fuzzer 93190 274147 18662 0 3 0x4000082 thrsleep syz-fuzzer 93190 394492 18662 0 3 0x4000082 thrsleep syz-fuzzer 93190 53772 18662 0 3 0x4000082 thrsleep syz-fuzzer 93190 57819 18662 0 3 0x4000082 thrsleep syz-fuzzer 18662 165606 28090 0 3 0x10008a pause ksh 28090 435808 82938 0 3 0x92 select sshd 98861 67310 1 0 3 0x100083 ttyin getty 82938 422662 1 0 3 0x80 select sshd 63361 276768 62339 73 3 0x100090 kqread syslogd 62339 118186 1 0 3 0x100082 netio syslogd 93981 221422 1 77 3 0x100090 poll dhclient 94904 359103 1 0 3 0x80 poll dhclient 70359 389203 0 0 3 0x14200 bored smr 5240 21092 0 0 2 0x14200 zerothread 28182 227756 0 0 3 0x14200 aiodoned aiodoned 31954 374100 0 0 3 0x14200 syncer update 87379 340605 0 0 3 0x14200 cleaner cleaner 43800 271867 0 0 3 0x14200 reaper reaper 18534 92288 0 0 3 0x14200 pgdaemon pagedaemon 33376 481658 0 0 3 0x14200 bored crynlk 47851 45595 0 0 3 0x14200 bored crypto 1123 39552 0 0 3 0x40014200 acpi0 acpi0 *64358 210285 0 0 7 0x14200 softnet 66088 156639 0 0 3 0x14200 bored systqmp 53492 119327 0 0 3 0x14200 bored systq 31655 315148 0 0 2 0x40014200 softclock 70040 267778 0 0 3 0x40014200 idle0 1 72764 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 9452 6323K 6453K 78643K 10633 0 pcb 13 8K 8K 78643K 25 0 rtable 83 2K 3K 78643K 241 0 ifaddr 32 9K 10K 78643K 58 0 sysctl 2 0K 0K 78643K 2 0 counters 20 16K 16K 78643K 25 0 ioctlops 0 0K 4K 78643K 21 0 iov 0 0K 16K 78643K 8 0 mount 1 1K 1K 78643K 1 0 vnodes 1215 76K 77K 78643K 1247 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 6 0K 0K 78643K 6 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1809 195K 288K 78643K 12938 0 file desc 5 13K 25K 78643K 85 0 sigio 0 0K 0K 78643K 2 0 proc 49 38K 63K 78643K 360 0 subproc 32 2K 2K 78643K 34 0 NFS srvsock 1 0K 0K 78643K 1 0 NFS daemon 1 16K 16K 78643K 1 0 in_multi 22 1K 2K 78643K 33 0 ether_multi 1 0K 0K 78643K 1 0 ISOFS mount 1 32K 32K 78643K 1 0 MSDOSFS mount 1 16K 16K 78643K 1 0 ttys 31 148K 148K 78643K 31 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 119 22K 43K 78643K 1036 0 UVM aobj 2 2K 2K 78643K 2 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 ip6_options 0 0K 0K 78643K 2 0 NDP 4 0K 0K 78643K 13 0 temp 67 3029K 3093K 78643K 1925 0 kqueue 3 4K 8K 78643K 13 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 8 0 4 1 0 1 1 0 8 0 rtpcb 80 21 0 19 1 0 1 1 0 8 0 rtentry 112 49 0 16 2 0 2 2 0 8 0 unpcb 120 63 0 55 1 0 1 1 0 8 0 syncache 264 7 0 6 2 1 1 1 0 8 0 tcpcb 544 32 0 26 1 0 1 1 0 8 0 inpcb 280 76 0 67 1 0 1 1 0 8 0 nd6 48 6 0 3 1 0 1 1 0 8 0 pfrule 1360 2 0 2 1 0 1 1 0 8 1 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 191 0 46 12 0 12 12 0 8 2 art_table 32 192 0 46 2 0 2 2 0 8 0 art_node 16 48 0 18 1 0 1 1 0 8 0 semapl 112 4 0 0 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 1495 0 100 88 0 88 88 0 8 0 ffsino 240 1495 0 100 83 0 83 83 0 8 0 nchpl 144 1841 0 236 60 0 60 60 0 8 0 uvmvnodes 72 1553 0 0 29 0 29 29 0 8 0 vnodes 208 1553 0 0 82 0 82 82 0 8 0 namei 1024 4563 0 4563 1 0 1 1 0 8 1 vmpool 528 1 0 1 1 0 1 1 0 8 1 scxspl 192 4457 0 4457 1 0 1 1 0 8 1 plimitpl 152 20 0 13 1 0 1 1 0 8 0 sigapl 424 271 0 243 4 0 4 4 0 8 0 futexpl 56 1237 0 1237 1 0 1 1 0 8 1 knotepl 112 69 0 50 1 0 1 1 0 8 0 kqueuepl 144 12 0 10 1 0 1 1 0 8 0 pipelkpl 16 82 0 72 1 0 1 1 0 8 0 pipepl 120 164 0 145 1 0 1 1 0 8 0 fdescpl 432 257 0 243 2 0 2 2 0 8 0 filepl 120 1416 0 1319 4 0 4 4 0 8 1 lockfpl 104 10 0 9 1 0 1 1 0 8 0 lockfspl 48 5 0 4 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 94 0 87 1 0 1 1 0 8 0 zombiepl 144 243 0 243 1 0 1 1 0 8 1 processpl 920 271 0 243 4 0 4 4 0 8 0 procpl 624 341 0 305 4 0 4 4 0 8 1 sockpl 400 160 0 141 3 0 3 3 0 8 1 mcl64k 65536 2 0 2 1 0 1 1 0 8 1 mcl16k 16384 1 0 1 1 0 1 1 0 8 1 mcl12k 12288 2 0 2 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 12 0 12 2 1 1 1 0 8 1 mcl2k 2048 71500 0 71452 18 4 14 16 0 8 7 mtagpl 80 8 0 4 2 1 1 1 0 8 0 mbufpl 256 113815 0 113743 13 2 11 11 0 8 3 bufpl 280 3336 0 127 230 0 230 230 0 8 0 anonpl 16 40054 0 25154 63 2 61 61 0 107 1 amapchunkpl 152 1412 0 1282 20 0 20 20 0 158 14 amappl16 192 1164 0 321 43 0 43 43 0 8 0 amappl15 184 28 0 26 1 0 1 1 0 8 0 amappl14 176 49 0 42 1 0 1 1 0 8 0 amappl13 168 26 0 23 1 0 1 1 0 8 0 amappl12 160 37 0 32 1 0 1 1 0 8 0 amappl11 152 75 0 65 1 0 1 1 0 8 0 amappl10 144 13 0 8 1 0 1 1 0 8 0 amappl9 136 370 0 369 1 0 1 1 0 8 0 amappl8 128 312 0 277 2 0 2 2 0 8 0 amappl7 120 106 0 95 1 0 1 1 0 8 0 amappl6 112 22 0 17 1 0 1 1 0 8 0 amappl5 104 202 0 189 1 0 1 1 0 8 0 amappl4 96 423 0 393 1 0 1 1 0 8 0 amappl3 88 107 0 100 1 0 1 1 0 8 0 amappl2 80 1274 0 1208 2 0 2 2 0 8 0 amappl1 72 14294 0 13884 24 8 16 17 0 8 7 amappl 80 567 0 526 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 1 0 0 1 0 1 1 0 8 0 uaddrrnd 24 258 0 244 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 258 0 244 1 0 1 1 0 8 0 vmmpekpl 168 5923 0 5898 2 0 2 2 0 8 0 vmmpepl 168 38064 0 36142 111 6 105 105 0 357 21 vmsppl 272 257 0 244 2 0 2 2 0 8 1 pdppl 4096 522 0 488 6 0 6 6 0 8 1 pvpl 32 136860 0 119015 151 0 151 151 0 265 7 pmappl 200 257 0 244 1 0 1 1 0 8 0 extentpl 40 53 0 36 1 0 1 1 0 8 0 phpool 112 243 0 9 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(ffffffff821dfb20) at panic+0x15c sys/kern/subr_prf.c:207 syn_cache_insert(fffffd805790ce78,ffff8000009f4ee0) at syn_cache_insert+0x944 sys/netinet/tcp_input.c:3235 syn_cache_add(ffff80001d6f7b88,ffff80001d6f7b38,fffffd8005db0868,28,fffffd806a8d8960,fffffd80578fba00) at syn_cache_add+0x66b tcp_input(ffff80001d6f7eb8,ffff80001d6f7ec4,6,18) at tcp_input+0x37d8 sys/netinet/tcp_input.c:830 ip_deliver(ffff80001d6f7eb8,ffff80001d6f7ec4,6,18) at ip_deliver+0x2e3 sys/netinet/ip_input.c:668 ip6_input_if(ffff80001d6f7eb8,ffff80001d6f7ec4,29,0,ffff800000677800) at ip6_input_if+0x1526 ip6_ours sys/netinet6/ip6_input.c:538 [inline] ip6_input_if(ffff80001d6f7eb8,ffff80001d6f7ec4,29,0,ffff800000677800) at ip6_input_if+0x1526 sys/netinet6/ip6_input.c:471 ipv6_input(ffff800000677800,fffffd80578fba00) at ipv6_input+0x48 sys/netinet6/ip6_input.c:171 if_input_local(ffff800000677800,fffffd80578fba00,18) at if_input_local+0x121 sys/net/if.c:779 loinput(ffff800000677800,fffffd80578fba00,0) at loinput+0x4f sys/net/if_loop.c:239 if_input_process(ffff800000677800,ffff80001d6f8008) at if_input_process+0xf8 if_ih_input sys/net/if.c:908 [inline] if_input_process(ffff800000677800,ffff80001d6f8008) at if_input_process+0xf8 sys/net/if.c:942 ifiq_process(ffff800000677bb8) at ifiq_process+0x80 sys/net/ifq.c:646 taskq_thread(ffff8000000290c0) at taskq_thread+0x52 sys/kern/kern_task.c:370 end trace frame: 0x0, count: -13 ddb> machine ddbcpu 1 No such command ddb> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff821dfb20) at panic+0x15c sys/kern/subr_prf.c:207 syn_cache_insert(fffffd805790ce78,ffff8000009f4ee0) at syn_cache_insert+0x944 sys/netinet/tcp_input.c:3235 syn_cache_add(ffff80001d6f7b88,ffff80001d6f7b38,fffffd8005db0868,28,fffffd806a8d8960,fffffd80578fba00) at syn_cache_add+0x66b tcp_input(ffff80001d6f7eb8,ffff80001d6f7ec4,6,18) at tcp_input+0x37d8 sys/netinet/tcp_input.c:830 ip_deliver(ffff80001d6f7eb8,ffff80001d6f7ec4,6,18) at ip_deliver+0x2e3 sys/netinet/ip_input.c:668 ip6_input_if(ffff80001d6f7eb8,ffff80001d6f7ec4,29,0,ffff800000677800) at ip6_input_if+0x1526 ip6_ours sys/netinet6/ip6_input.c:538 [inline] ip6_input_if(ffff80001d6f7eb8,ffff80001d6f7ec4,29,0,ffff800000677800) at ip6_input_if+0x1526 sys/netinet6/ip6_input.c:471 ipv6_input(ffff800000677800,fffffd80578fba00) at ipv6_input+0x48 sys/netinet6/ip6_input.c:171 if_input_local(ffff800000677800,fffffd80578fba00,18) at if_input_local+0x121 sys/net/if.c:779 loinput(ffff800000677800,fffffd80578fba00,0) at loinput+0x4f sys/net/if_loop.c:239 if_input_process(ffff800000677800,ffff80001d6f8008) at if_input_process+0xf8 if_ih_input sys/net/if.c:908 [inline] if_input_process(ffff800000677800,ffff80001d6f8008) at if_input_process+0xf8 sys/net/if.c:942 ifiq_process(ffff800000677bb8) at ifiq_process+0x80 sys/net/ifq.c:646 taskq_thread(ffff8000000290c0) at taskq_thread+0x52 sys/kern/kern_task.c:370 end trace frame: 0x0, count: -13