panic: syn_cache_insert: bucketoverflow: impossible Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *492822 54618 0 0x14000 0x200 0 softnet db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff821c5da7) at panic+0x15c sys/kern/subr_prf.c:207 syn_cache_insert(fffffd805f151d80,ffff8000009f4440) at syn_cache_insert+0x944 sys/netinet/tcp_input.c:3235 syn_cache_add(ffff80001d6f86e8,ffff80001d6f8698,fffffd80586333c4,14,fffffd806b7a5640,fffffd8058633300) at syn_cache_add+0x66b tcp_input(ffff80001d6f89e8,ffff80001d6f89f4,6,2) at tcp_input+0x37d8 sys/netinet/tcp_input.c:830 ip_deliver(ffff80001d6f89e8,ffff80001d6f89f4,6,2) at ip_deliver+0x2e3 sys/netinet/ip_input.c:668 ip_ours(ffff80001d6f89e8,ffff80001d6f89f4,2,0) at ip_ours+0x4fe sys/netinet/ip_input.c:563 ip_input_if(ffff80001d6f89e8,ffff80001d6f89f4,4,0,ffff800000677800) at ip_input_if+0x571 ipv4_input(ffff800000677800,fffffd8058633300) at ipv4_input+0x48 sys/netinet/ip_input.c:215 if_input_local(ffff800000677800,fffffd8058633300,2) at if_input_local+0xf9 sys/net/if.c:775 loinput(ffff800000677800,fffffd8058633300,0) at loinput+0x4f sys/net/if_loop.c:239 if_input_process(ffff800000677800,ffff80001d6f8b38) at if_input_process+0xf8 if_ih_input sys/net/if.c:908 [inline] if_input_process(ffff800000677800,ffff80001d6f8b38) 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: 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: bucketoverflow: impossible ddb> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff821c5da7) at panic+0x15c sys/kern/subr_prf.c:207 syn_cache_insert(fffffd805f151d80,ffff8000009f4440) at syn_cache_insert+0x944 sys/netinet/tcp_input.c:3235 syn_cache_add(ffff80001d6f86e8,ffff80001d6f8698,fffffd80586333c4,14,fffffd806b7a5640,fffffd8058633300) at syn_cache_add+0x66b tcp_input(ffff80001d6f89e8,ffff80001d6f89f4,6,2) at tcp_input+0x37d8 sys/netinet/tcp_input.c:830 ip_deliver(ffff80001d6f89e8,ffff80001d6f89f4,6,2) at ip_deliver+0x2e3 sys/netinet/ip_input.c:668 ip_ours(ffff80001d6f89e8,ffff80001d6f89f4,2,0) at ip_ours+0x4fe sys/netinet/ip_input.c:563 ip_input_if(ffff80001d6f89e8,ffff80001d6f89f4,4,0,ffff800000677800) at ip_input_if+0x571 ipv4_input(ffff800000677800,fffffd8058633300) at ipv4_input+0x48 sys/netinet/ip_input.c:215 if_input_local(ffff800000677800,fffffd8058633300,2) at if_input_local+0xf9 sys/net/if.c:775 loinput(ffff800000677800,fffffd8058633300,0) at loinput+0x4f sys/net/if_loop.c:239 if_input_process(ffff800000677800,ffff80001d6f8b38) at if_input_process+0xf8 if_ih_input sys/net/if.c:908 [inline] if_input_process(ffff800000677800,ffff80001d6f8b38) 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: -14 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff80001d6f8260 rbx 0xffff80001d6f8310 rdx 0x2 rcx 0 rax 0x1 r8 0xffffffff8200075f kprintf+0x15f r9 0x1 r10 0x2 r11 0xeeeb76087f8f60d1 r12 0x3000000008 r13 0xffff80001d6f8270 r14 0x100 r15 0x1 rip 0xffffffff811a6e98 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff80001d6f8250 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (softnet) pid=492822 stat=onproc flags process=14000 proc=200 pri=32, usrpri=50, nice=20 forw=0xffffffffffffffff, list=0xffff80001d6d1ea0,0xffff80001d6d1760 process=0xffff8000ffffeac8 user=0xffff80001d6f3000, vmspace=0xffffffff825eac10 estcpu=0, cpticks=0, pctcpu=0.0 user=0, sys=0, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 81469 17358 91283 0 2 0 syz-executor.0 81469 237121 91283 0 3 0x4000080 netcon2 syz-executor.0 91283 403196 44832 0 3 0x82 nanosleep syz-executor.0 20371 77704 0 0 3 0x14200 bored sosplice 33775 495562 0 0 3 0x14280 nfsidl nfsio 5411 439839 0 0 3 0x14280 nfsidl nfsio 73964 56558 0 0 3 0x14280 nfsidl nfsio 26762 122692 0 0 3 0x14280 nfsidl nfsio 12505 69984 0 0 3 0x14280 nfsidl nfsio 13065 400094 0 0 3 0x14280 nfsidl nfsio 10866 503225 0 0 3 0x14280 nfsidl nfsio 11504 177466 0 0 3 0x14280 nfsidl nfsio 92129 39301 0 0 3 0x14280 nfsidl nfsio 36970 336212 0 0 3 0x14280 nfsidl nfsio 82725 111425 0 0 3 0x14280 nfsidl nfsio 43188 372992 0 0 3 0x14280 nfsidl nfsio 78355 328351 0 0 3 0x14280 nfsidl nfsio 26171 98583 0 0 3 0x14280 nfsidl nfsio 30926 447872 0 0 3 0x14280 nfsidl nfsio 60215 364417 0 0 3 0x14280 nfsidl nfsio 61851 35266 0 0 3 0x14280 nfsidl nfsio 87761 427553 0 0 3 0x14280 nfsidl nfsio 94142 500006 0 0 3 0x14280 nfsidl nfsio 17520 53999 0 0 3 0x14280 nfsidl nfsio 79917 400073 44832 0 3 0x82 piperd syz-executor.1 44832 466932 55041 0 3 0x82 thrsleep syz-fuzzer 44832 332300 55041 0 3 0x4000082 nanosleep syz-fuzzer 44832 58440 55041 0 2 0x4000002 syz-fuzzer 44832 125141 55041 0 3 0x4000082 thrsleep syz-fuzzer 44832 481370 55041 0 3 0x4000082 thrsleep syz-fuzzer 44832 305089 55041 0 3 0x4000082 thrsleep syz-fuzzer 44832 204430 55041 0 3 0x4000082 thrsleep syz-fuzzer 44832 385691 55041 0 2 0x4000002 syz-fuzzer 55041 483810 52145 0 3 0x10008a pause ksh 52145 338714 21369 0 3 0x92 select sshd 99734 46375 1 0 3 0x100083 ttyin getty 21369 264882 1 0 3 0x80 select sshd 1384 422350 47024 73 3 0x100090 kqread syslogd 47024 213899 1 0 3 0x100082 netio syslogd 44840 31875 1 77 3 0x100090 poll dhclient 99273 332098 1 0 3 0x80 poll dhclient 7199 166862 0 0 3 0x14200 bored smr 15397 356437 0 0 2 0x14200 zerothread 61625 59979 0 0 3 0x14200 aiodoned aiodoned 58393 506496 0 0 3 0x14200 syncer update 76823 101035 0 0 3 0x14200 cleaner cleaner 75013 493791 0 0 3 0x14200 reaper reaper 52941 167691 0 0 3 0x14200 pgdaemon pagedaemon 32744 519302 0 0 3 0x14200 bored crynlk 7838 227048 0 0 3 0x14200 bored crypto 50301 268182 0 0 3 0x40014200 acpi0 acpi0 *54618 492822 0 0 7 0x14200 softnet 94657 299796 0 0 3 0x14200 bored systqmp 92462 100534 0 0 3 0x14200 bored systq 55494 473405 0 0 3 0x40014200 bored softclock 42998 23636 0 0 3 0x40014200 idle0 1 53 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 9525 6349K 6716K 78643K 11635 0 pcb 13 8K 8K 78643K 115 0 rtable 130 8K 8K 78643K 543 0 ifaddr 106 21K 21K 78643K 235 0 counters 21 16K 17K 78643K 39 0 ioctlops 0 0K 4K 78643K 119 0 iov 0 0K 12K 78643K 96 0 mount 1 1K 1K 78643K 1 0 vnodes 1224 77K 77K 78643K 1576 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 0K 1K 78643K 56 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1809 195K 288K 78643K 12938 0 file desc 5 13K 25K 78643K 701 0 sigio 0 0K 0K 78643K 4 0 proc 49 38K 63K 78643K 478 0 subproc 32 2K 2K 78643K 70 0 NFS srvsock 1 0K 0K 78643K 1 0 NFS daemon 1 16K 16K 78643K 1 0 ip_moptions 0 0K 0K 78643K 56 0 in_multi 101 4K 4K 78643K 197 0 ether_multi 1 0K 0K 78643K 19 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 249 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 143 121K 123K 78643K 2853 0 UVM aobj 21 4K 5K 78643K 28 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 ip6_options 0 0K 0K 78643K 74 0 NDP 15 0K 0K 78643K 45 0 temp 120 3038K 3102K 78643K 25522 0 kqueue 3 4K 18K 78643K 27 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 13 0 6 1 0 1 1 0 8 0 rtpcb 80 48 0 46 1 0 1 1 0 8 0 rtentry 112 97 0 51 2 0 2 2 0 8 0 unpcb 120 361 0 353 1 0 1 1 0 8 0 syncache 264 11 0 10 4 3 1 1 0 8 0 tcpqe 32 413 0 413 2 2 0 1 0 8 0 tcpcb 544 1339 0 1333 1 0 1 1 0 8 0 ipq 40 10 0 10 4 4 0 1 0 8 0 ipqe 40 368 0 368 4 4 0 1 0 8 0 inpcb 280 1775 0 1766 8 7 1 2 0 8 0 rttmr 72 3 0 2 2 1 1 1 0 8 0 nd6 48 19 0 12 1 0 1 1 0 8 0 ppxss 1128 2 0 2 2 2 0 1 0 8 0 pfstscr 40 4 0 2 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 32 0 23 1 0 1 1 0 8 0 pftag 88 10 0 6 2 1 1 1 0 8 0 pfstitem 24 3 0 0 1 0 1 1 0 8 0 pfstkey 112 5 0 2 1 0 1 1 0 8 0 pfstate 328 3 0 1 1 0 1 1 0 8 0 pfrule 1360 34 0 20 3 1 2 2 0 8 0 art_heap8 4096 2 0 0 2 0 2 2 0 8 0 art_heap4 256 425 0 204 16 2 14 15 0 8 0 art_table 32 427 0 204 2 0 2 2 0 8 0 art_node 16 94 0 51 1 0 1 1 0 8 0 sysvmsgpl 40 6 0 2 2 1 1 1 0 8 0 semupl 112 3 0 3 1 1 0 1 0 8 0 semapl 112 50 0 40 1 0 1 1 0 8 0 shmpl 112 26 0 8 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 2344 0 948 88 0 88 88 0 8 0 ffsino 240 2344 0 948 83 0 83 83 0 8 0 nchpl 144 3460 0 1878 60 0 60 60 0 8 0 uvmvnodes 72 2628 0 0 48 0 48 48 0 8 0 vnodes 208 2628 0 0 139 0 139 139 0 8 0 namei 1024 9499 0 9499 5 4 1 1 0 8 1 vcpupl 1984 10 0 0 2 0 2 2 0 8 0 vmpool 528 13 0 3 1 0 1 1 0 8 0 pfiaddrpl 120 10 0 4 3 2 1 1 0 8 0 scxspl 192 10377 0 10377 8 7 1 1 0 8 1 plimitpl 152 56 0 49 1 0 1 1 0 8 0 sigapl 424 902 0 853 6 0 6 6 0 8 0 futexpl 56 15416 0 15416 4 3 1 1 0 8 1 knotepl 112 165 0 146 2 0 2 2 0 8 1 kqueuepl 144 100 0 94 1 0 1 1 0 8 0 pipelkpl 16 158 0 148 1 0 1 1 0 8 0 pipepl 120 316 0 297 1 0 1 1 0 8 0 fdescpl 432 867 0 853 2 0 2 2 0 8 0 filepl 120 6034 0 5937 7 3 4 4 0 8 1 lockfpl 104 139 0 138 1 0 1 1 0 8 0 lockfspl 48 49 0 48 1 0 1 1 0 8 0 sessionpl 112 19 0 9 1 0 1 1 0 8 0 pgrppl 48 23 0 13 1 0 1 1 0 8 0 ucredpl 96 547 0 540 1 0 1 1 0 8 0 zombiepl 144 853 0 853 5 4 1 1 0 8 1 processpl 920 902 0 853 7 0 7 7 0 8 0 procpl 624 2042 0 1985 5 0 5 5 0 8 0 sosppl 128 5 0 5 3 3 0 1 0 8 0 sockpl 400 2185 0 2166 6 3 3 3 0 8 1 mcl64k 65536 83 0 82 13 12 1 1 0 8 0 mcl16k 16384 5 0 5 5 5 0 1 0 8 0 mcl12k 12288 31 0 31 15 14 1 1 0 8 1 mcl9k 9216 12 0 12 9 9 0 1 0 8 0 mcl8k 8192 13 0 13 9 9 0 1 0 8 0 mcl4k 4096 63 0 63 10 9 1 1 0 8 1 mcl2k2 2112 1 0 1 1 1 0 1 0 8 0 mcl2k 2048 72811 0 72755 19 11 8 16 0 8 0 mtagpl 80 87 0 29 3 1 2 2 0 8 0 mbufpl 256 123540 0 123197 68 46 22 23 0 8 0 bufpl 280 5122 0 128 357 0 357 357 0 8 0 anonpl 16 89180 0 73523 78 13 65 68 0 107 0 amapchunkpl 152 4542 0 4412 19 6 13 13 0 158 6 amappl16 192 3947 0 3048 62 17 45 53 0 8 0 amappl15 184 12 0 9 1 0 1 1 0 8 0 amappl14 176 37 0 33 1 0 1 1 0 8 0 amappl13 168 49 0 45 1 0 1 1 0 8 0 amappl12 160 9 0 8 1 0 1 1 0 8 0 amappl11 152 54 0 44 1 0 1 1 0 8 0 amappl10 144 521 0 516 1 0 1 1 0 8 0 amappl9 136 487 0 485 1 0 1 1 0 8 0 amappl8 128 505 0 462 2 0 2 2 0 8 0 amappl7 120 571 0 559 1 0 1 1 0 8 0 amappl6 112 25 0 21 1 0 1 1 0 8 0 amappl5 104 789 0 776 1 0 1 1 0 8 0 amappl4 96 459 0 430 1 0 1 1 0 8 0 amappl3 88 138 0 132 1 0 1 1 0 8 0 amappl2 80 5756 0 5689 2 0 2 2 0 8 0 amappl1 72 25589 0 25175 23 13 10 17 0 8 0 amappl 80 2293 0 2245 3 1 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 27 0 7 1 0 1 1 0 8 0 uaddrrnd 24 880 0 856 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 880 0 856 1 0 1 1 0 8 0 vmmpekpl 168 9645 0 9608 3 1 2 2 0 8 0 vmmpepl 168 108367 0 106366 202 114 88 134 0 357 0 vmsppl 272 879 0 856 3 1 2 2 0 8 0 pdppl 4096 1766 0 1722 9 3 6 6 0 8 0 pvpl 32 266923 0 248177 196 39 157 166 0 265 3 pmappl 200 879 0 856 3 1 2 2 0 8 0 extentpl 40 53 0 36 1 0 1 1 0 8 0 phpool 112 350 0 108 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(ffffffff821c5da7) at panic+0x15c sys/kern/subr_prf.c:207 syn_cache_insert(fffffd805f151d80,ffff8000009f4440) at syn_cache_insert+0x944 sys/netinet/tcp_input.c:3235 syn_cache_add(ffff80001d6f86e8,ffff80001d6f8698,fffffd80586333c4,14,fffffd806b7a5640,fffffd8058633300) at syn_cache_add+0x66b tcp_input(ffff80001d6f89e8,ffff80001d6f89f4,6,2) at tcp_input+0x37d8 sys/netinet/tcp_input.c:830 ip_deliver(ffff80001d6f89e8,ffff80001d6f89f4,6,2) at ip_deliver+0x2e3 sys/netinet/ip_input.c:668 ip_ours(ffff80001d6f89e8,ffff80001d6f89f4,2,0) at ip_ours+0x4fe sys/netinet/ip_input.c:563 ip_input_if(ffff80001d6f89e8,ffff80001d6f89f4,4,0,ffff800000677800) at ip_input_if+0x571 ipv4_input(ffff800000677800,fffffd8058633300) at ipv4_input+0x48 sys/netinet/ip_input.c:215 if_input_local(ffff800000677800,fffffd8058633300,2) at if_input_local+0xf9 sys/net/if.c:775 loinput(ffff800000677800,fffffd8058633300,0) at loinput+0x4f sys/net/if_loop.c:239 if_input_process(ffff800000677800,ffff80001d6f8b38) at if_input_process+0xf8 if_ih_input sys/net/if.c:908 [inline] if_input_process(ffff800000677800,ffff80001d6f8b38) 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: -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(ffffffff821c5da7) at panic+0x15c sys/kern/subr_prf.c:207 syn_cache_insert(fffffd805f151d80,ffff8000009f4440) at syn_cache_insert+0x944 sys/netinet/tcp_input.c:3235 syn_cache_add(ffff80001d6f86e8,ffff80001d6f8698,fffffd80586333c4,14,fffffd806b7a5640,fffffd8058633300) at syn_cache_add+0x66b tcp_input(ffff80001d6f89e8,ffff80001d6f89f4,6,2) at tcp_input+0x37d8 sys/netinet/tcp_input.c:830 ip_deliver(ffff80001d6f89e8,ffff80001d6f89f4,6,2) at ip_deliver+0x2e3 sys/netinet/ip_input.c:668 ip_ours(ffff80001d6f89e8,ffff80001d6f89f4,2,0) at ip_ours+0x4fe sys/netinet/ip_input.c:563 ip_input_if(ffff80001d6f89e8,ffff80001d6f89f4,4,0,ffff800000677800) at ip_input_if+0x571 ipv4_input(ffff800000677800,fffffd8058633300) at ipv4_input+0x48 sys/netinet/ip_input.c:215 if_input_local(ffff800000677800,fffffd8058633300,2) at if_input_local+0xf9 sys/net/if.c:775 loinput(ffff800000677800,fffffd8058633300,0) at loinput+0x4f sys/net/if_loop.c:239 if_input_process(ffff800000677800,ffff80001d6f8b38) at if_input_process+0xf8 if_ih_input sys/net/if.c:908 [inline] if_input_process(ffff800000677800,ffff80001d6f8b38) 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: -14