panic(ffffffff82407659) at panic+0x15c sys/kern/subr_prf.c:207 pool_cache_get(ffffffff828d9a80) at pool_cache_get+0x323 pool_cache_item_magic_check sys/kern/subr_pool.c:1781 [inline] pool_cache_get(ffffffff828d9a80) at pool_cache_get+0x323 sys/kern/subr_pool.c:1884 pool_get(ffffffff828d9a80,2) at pool_get+0x91 sys/kern/subr_pool.c:572 m_get(2,1) at m_get+0x4c sys/kern/uipc_mbuf.c:250 ip6_output(fffffd807cde3a00,ffffffff827bdb58,0,0,ffff800021eff238,0) at ip6_output+0x203 sys/netinet6/ip6_output.c:198 mld6_sendpkt(ffff800000aef680,84,ffffffff82726e00) at mld6_sendpkt+0x2da sys/netinet6/mld6.c:465 in6_delmulti(ffff800000aef680) at in6_delmulti+0xbb sys/netinet6/in6.c:1092 in6_purgeaddr(ffff800000b02600) at in6_purgeaddr+0x195 in6_leavegroup sys/netinet6/in6.c:1156 [inline] in6_purgeaddr(ffff800000b02600) at in6_purgeaddr+0x195 sys/netinet6/in6.c:925 in6_ioctl_change_ifaddr(8080691a,ffff800021eff660,ffff800000af5000) at in6_ioctl_change_ifaddr+0xa2f ifioctl(fffffd8065af4018,8080691a,ffff800021eff660,ffff800020e034f8) at ifioctl+0xe70 sys/net/if.c:2180 soo_ioctl(fffffd8066cf2ef8,8080691a,ffff800021eff660,ffff800020e034f8) at soo_ioctl+0x27c sys/kern/sys_socket.c:138 sys_ioctl(ffff800020e034f8,ffff800021eff778,ffff800021eff7c0) at sys_ioctl+0x4a5 syscall(ffff800021eff840) at syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff800021eff840) at syscall+0x4a4 sys/arch/amd64/amd64/trap.c:570 end trace frame: 0xffff800021eff8c0, count: 0 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 pool_cache_item_magic_check: mbufpl cpu free list modified: item addr 0xfffffd806b0e8500+16 0x0!=0xbc64d5e05df264 ddb{0}> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff82407659) at panic+0x15c sys/kern/subr_prf.c:207 pool_cache_get(ffffffff828d9a80) at pool_cache_get+0x323 pool_cache_item_magic_check sys/kern/subr_pool.c:1781 [inline] pool_cache_get(ffffffff828d9a80) at pool_cache_get+0x323 sys/kern/subr_pool.c:1884 pool_get(ffffffff828d9a80,2) at pool_get+0x91 sys/kern/subr_pool.c:572 m_get(2,1) at m_get+0x4c sys/kern/uipc_mbuf.c:250 ip6_output(fffffd807cde3a00,ffffffff827bdb58,0,0,ffff800021eff238,0) at ip6_output+0x203 sys/netinet6/ip6_output.c:198 mld6_sendpkt(ffff800000aef680,84,ffffffff82726e00) at mld6_sendpkt+0x2da sys/netinet6/mld6.c:465 in6_delmulti(ffff800000aef680) at in6_delmulti+0xbb sys/netinet6/in6.c:1092 in6_purgeaddr(ffff800000b02600) at in6_purgeaddr+0x195 in6_leavegroup sys/netinet6/in6.c:1156 [inline] in6_purgeaddr(ffff800000b02600) at in6_purgeaddr+0x195 sys/netinet6/in6.c:925 in6_ioctl_change_ifaddr(8080691a,ffff800021eff660,ffff800000af5000) at in6_ioctl_change_ifaddr+0xa2f ifioctl(fffffd8065af4018,8080691a,ffff800021eff660,ffff800020e034f8) at ifioctl+0xe70 sys/net/if.c:2180 soo_ioctl(fffffd8066cf2ef8,8080691a,ffff800021eff660,ffff800020e034f8) at soo_ioctl+0x27c sys/kern/sys_socket.c:138 sys_ioctl(ffff800020e034f8,ffff800021eff778,ffff800021eff7c0) at sys_ioctl+0x4a5 syscall(ffff800021eff840) at syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff800021eff840) at syscall+0x4a4 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x8c89a365b20, count: -15 ddb{0}> show registers rdi 0 rsi 0x1 rbp 0xffff800021efee60 rbx 0xffff800021efef10 rdx 0x8b rcx 0x2 rax 0x1 r8 0xffffffff8150d54f kprintf+0x16f r9 0x1 r10 0x2 r11 0xc33b7732ca384e73 r12 0x3000000008 r13 0xffff800021efee70 r14 0x100 r15 0x1 rip 0xffffffff818b9b58 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff800021efee50 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb{0}> show proc PROC (syz-executor.1) pid=11895 stat=onproc flags process=0 proc=4000000 pri=32, usrpri=86, nice=20 forw=0xffffffffffffffff, list=0xffff800020e03eb8,0xffff800020e03c58 process=0xffff800020ed1388 user=0xffff800021efa000, vmspace=0xfffffd807effe730 estcpu=36, cpticks=2, pctcpu=0.0 user=0, sys=2, intr=0 ddb{0}> ps PID TID PPID UID S FLAGS WAIT COMMAND 77216 404079 10903 0 2 0 syz-executor.1 77216 225458 10903 0 2 0x4000000 syz-executor.1 *77216 11895 10903 0 7 0x4000000 syz-executor.1 77216 204980 10903 0 3 0x4000080 fsleep syz-executor.1 89807 131813 8033 0 2 0 syz-executor.0 89807 261908 8033 0 7 0x4000000 syz-executor.0 26243 338972 0 0 3 0x14200 bored sosplice 10903 68706 57950 0 3 0x82 nanosleep syz-executor.1 8033 507738 57950 0 3 0x82 nanosleep syz-executor.0 57950 503157 63617 0 3 0x82 nanosleep syz-fuzzer 57950 481601 63617 0 3 0x4000082 nanosleep syz-fuzzer 57950 459305 63617 0 3 0x4000082 thrsleep syz-fuzzer 57950 280158 63617 0 3 0x4000082 thrsleep syz-fuzzer 57950 252652 63617 0 3 0x4000082 thrsleep syz-fuzzer 57950 153976 63617 0 3 0x4000082 thrsleep syz-fuzzer 57950 421280 63617 0 3 0x4000082 thrsleep syz-fuzzer 57950 106972 63617 0 3 0x4000082 thrsleep syz-fuzzer 57950 217593 63617 0 3 0x4000082 kqread syz-fuzzer 57950 306941 63617 0 3 0x4000082 thrsleep syz-fuzzer 63617 318813 9634 0 3 0x10008a pause ksh 9634 298203 29951 0 3 0x92 select sshd 23419 292685 1 0 3 0x100083 ttyin getty 29951 138440 1 0 3 0x80 select sshd 44759 274286 43930 74 3 0x100092 bpf pflogd 43930 121838 1 0 3 0x80 netio pflogd 46761 284580 68152 73 3 0x100090 kqread syslogd 68152 206279 1 0 3 0x100082 netio syslogd 96889 424182 1 77 3 0x100090 poll dhclient 46804 132099 1 0 3 0x80 poll dhclient 71273 282428 0 0 3 0x14200 bored smr 91205 155420 0 0 2 0x14200 zerothread 72411 75492 0 0 3 0x14200 aiodoned aiodoned 77387 264461 0 0 3 0x14200 syncer update 72794 211633 0 0 3 0x14200 cleaner cleaner 76809 117023 0 0 3 0x14200 reaper reaper 54244 1495 0 0 3 0x14200 pgdaemon pagedaemon 26884 174388 0 0 3 0x14200 bored crynlk 76667 304402 0 0 3 0x14200 bored crypto 95476 413636 0 0 3 0x40014200 acpi0 acpi0 34496 399393 0 0 3 0x40014200 idle1 6944 257126 0 0 3 0x14200 bored softnet 22331 310170 0 0 3 0x14200 bored systqmp 76327 38720 0 0 3 0x14200 bored systq 87543 509757 0 0 3 0x40014200 bored softclock 17699 281270 0 0 3 0x40014200 idle0 1 344888 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{0}> show all locks Process 77216 (syz-executor.1) thread 0xffff800020e034f8 (11895) exclusive rwlock netlock r = 0 (0xffffffff8273b8d8) #0 witness_lock+0x4c7 stacktrace_save sys/sys/stacktrace.h:36 [inline] #0 witness_lock+0x4c7 sys/kern/subr_witness.c:1164 #1 in6_ioctl_change_ifaddr+0xab #2 ifioctl+0xe70 sys/net/if.c:2180 #3 soo_ioctl+0x27c sys/kern/sys_socket.c:138 #4 sys_ioctl+0x4a5 #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 exclusive kernel_lock &kernel_lock r = 0 (0xffffffff828fd198) #0 witness_lock+0x4c7 stacktrace_save sys/sys/stacktrace.h:36 [inline] #0 witness_lock+0x4c7 sys/kern/subr_witness.c:1164 #1 soo_ioctl+0x26a sys/kern/sys_socket.c:138 #2 sys_ioctl+0x4a5 #3 syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:102 [inline] #3 syscall+0x4a4 sys/arch/amd64/amd64/trap.c:570 #4 Xsyscall+0x128 ddb{0}> show malloc Type InUse MemUse HighUse Limit Requests Type Lim devbuf 9492 6413K 6670K 78643K 11106 0 pcb 13 8K 8K 78643K 53 0 rtable 114 5K 8K 78643K 349 0 ifaddr 62 13K 14K 78643K 129 0 counters 43 33K 34K 78643K 59 0 ioctlops 0 0K 4K 78643K 1539 0 iov 0 0K 16K 78643K 29 0 mount 1 1K 1K 78643K 1 0 vnodes 1230 77K 78K 78643K 1394 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 1K 78643K 157 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1824 197K 290K 78643K 13058 0 file desc 6 17K 25K 78643K 444 0 proc 61 63K 83K 78643K 465 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 28 0 in_multi 41 2K 2K 78643K 89 0 ether_multi 1 0K 0K 78643K 6 0 mrt 0 0K 0K 78643K 1 0 ISOFS mount 1 32K 32K 78643K 1 0 MSDOSFS mount 1 16K 16K 78643K 1 0 ttys 37 175K 175K 78643K 37 0 exec 0 0K 1K 78643K 225 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 138 39K 41K 78643K 2366 0 UVM aobj 10 2K 3K 78643K 18 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 ip6_options 0 0K 0K 78643K 40 0 NDP 9 0K 0K 78643K 25 0 temp 94 3862K 3926K 78643K 3133 0 kqueue 3 4K 20K 78643K 73 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 6 0 0 1 0 1 1 0 8 0 plcache 128 20 0 0 1 0 1 1 0 8 0 rtpcb 80 39 0 37 1 0 1 1 0 8 0 rtentry 112 62 0 19 2 0 2 2 0 8 0 unpcb 120 311 0 299 1 0 1 1 0 8 0 syncache 264 4 0 4 1 1 0 1 0 8 0 sackhl 24 1 0 1 1 1 0 1 0 8 0 tcpqe 32 933 0 933 1 1 0 1 0 8 0 tcpcb 544 240 0 236 2 0 2 2 0 8 1 inpcb 296 689 0 676 2 0 2 2 0 8 1 nd6 48 14 0 8 1 0 1 1 0 8 0 pkpcb 40 6 0 6 2 1 1 1 0 8 1 ppxss 1136 2 0 2 2 2 0 1 0 8 0 pffrag 232 3 0 3 1 1 0 1 0 482 0 pffrnode 88 3 0 3 1 1 0 1 0 8 0 pffrent 40 97 0 97 2 1 1 1 0 8 1 pfosfp 40 847 0 423 5 0 5 5 0 8 0 pfosfpen 112 1429 0 714 21 0 21 21 0 8 0 pfrktable 1344 26 0 22 1 0 1 1 0 8 0 pfstitem 24 18 0 7 1 0 1 1 0 8 0 pfstkey 112 20 0 9 1 0 1 1 0 8 0 pfstate 328 18 0 8 2 0 2 2 0 8 0 pfrule 1360 36 0 20 3 1 2 2 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 288 0 102 13 0 13 13 0 8 0 art_table 32 289 0 102 2 0 2 2 0 8 0 art_node 16 61 0 22 1 0 1 1 0 8 0 semupl 112 3 0 3 1 1 0 1 0 8 0 semapl 112 149 0 139 1 0 1 1 0 8 0 shmpl 112 15 0 8 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 1962 0 555 89 0 89 89 0 8 0 ffsino 272 1962 0 555 96 1 95 95 0 8 0 nchpl 144 2776 0 1174 61 0 61 61 0 8 0 uvmvnodes 72 2128 0 0 39 0 39 39 0 8 0 vnodes 208 2128 0 0 112 0 112 112 0 8 0 namei 1024 7381 0 7381 2 1 1 1 0 8 1 percpumem 16 40 0 8 1 0 1 1 0 8 0 vcpupl 1984 2 0 0 1 0 1 1 0 8 0 vmpool 560 3 0 1 1 0 1 1 0 8 0 pfiaddrpl 120 12 0 4 1 0 1 1 0 8 0 scxspl 192 8145 0 8145 11 9 2 7 0 8 2 plimitpl 152 43 0 35 1 0 1 1 0 8 0 sigapl 424 660 0 627 4 0 4 4 0 8 0 futexpl 56 6313 0 6312 1 0 1 1 0 8 0 knotepl 112 129 0 110 2 1 1 2 0 8 0 kqueuepl 144 373 0 370 1 0 1 1 0 8 0 pipepl 304 141 0 131 4 2 2 2 0 8 1 fdescpl 496 644 0 627 3 0 3 3 0 8 0 filepl 152 3800 0 3690 7 1 6 6 0 8 1 lockfpl 104 113 0 112 1 0 1 1 0 8 0 lockfspl 48 38 0 37 1 0 1 1 0 8 0 sessionpl 112 18 0 7 1 0 1 1 0 8 0 pgrppl 48 22 0 11 1 0 1 1 0 8 0 ucredpl 96 358 0 349 1 0 1 1 0 8 0 zombiepl 144 627 0 627 2 1 1 1 0 8 1 processpl 992 660 0 627 6 1 5 5 0 8 0 procpl 624 1572 0 1526 4 0 4 4 0 8 0 sosppl 128 15 0 15 2 1 1 1 0 8 1 sockpl 400 1049 0 1022 8 4 4 6 0 8 1 mcl64k 65536 5 0 0 1 0 1 1 0 8 0 mcl16k 16384 1 0 0 1 0 1 1 0 8 0 mcl12k 12288 5 0 0 1 0 1 1 0 8 0 mcl9k 9216 3 0 0 1 0 1 1 0 8 0 mcl8k 8192 5 0 0 1 0 1 1 0 8 0 mcl4k 4096 3 0 0 1 0 1 1 0 8 0 mcl2k 2048 203 0 0 25 0 25 25 0 8 0 mtagpl 96 34 0 0 1 0 1 1 0 8 0 mbufpl 256 309 0 0 19 0 19 19 0 8 0 bufpl 280 4009 0 133 277 0 277 277 0 8 0 anonpl 16 85736 0 68774 86 3 83 85 0 124 12 amapchunkpl 152 3766 0 3616 12 1 11 11 0 158 4 amappl16 192 2830 0 1919 58 6 52 58 0 8 6 amappl15 184 2 0 1 1 0 1 1 0 8 0 amappl14 176 442 0 429 1 0 1 1 0 8 0 amappl13 168 29 0 26 1 0 1 1 0 8 0 amappl12 160 4 0 3 2 1 1 1 0 8 0 amappl11 152 469 0 449 1 0 1 1 0 8 0 amappl10 144 17 0 14 1 0 1 1 0 8 0 amappl9 136 383 0 382 1 0 1 1 0 8 0 amappl8 128 363 0 321 2 0 2 2 0 8 0 amappl7 120 118 0 106 1 0 1 1 0 8 0 amappl6 112 437 0 428 2 1 1 1 0 8 0 amappl5 104 144 0 129 1 0 1 1 0 8 0 amappl4 96 900 0 871 1 0 1 1 0 8 0 amappl3 88 127 0 121 1 0 1 1 0 8 0 amappl2 80 4216 0 4140 2 0 2 2 0 8 0 amappl1 72 28192 0 27723 23 13 10 18 0 8 0 amappl 80 1824 0 1776 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 17 0 8 1 0 1 1 0 8 0 uaddrrnd 24 647 0 628 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 647 0 628 1 0 1 1 0 8 0 vmmpekpl 168 8885 0 8850 2 0 2 2 0 8 0 vmmpepl 168 89456 0 87242 131 26 105 115 0 357 8 vmsppl 368 646 0 628 2 0 2 2 0 8 0 pdppl 4096 1301 0 1258 7 1 6 6 0 8 0 pvpl 32 282989 0 262693 203 4 199 202 0 265 31 pmappl 232 646 0 628 3 1 2 2 0 8 0 extentpl 40 53 0 36 1 0 1 1 0 8 0 phpool 112 280 0 10 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(ffffffff82407659) at panic+0x15c sys/kern/subr_prf.c:207 pool_cache_get(ffffffff828d9a80) at pool_cache_get+0x323 pool_cache_item_magic_check sys/kern/subr_pool.c:1781 [inline] pool_cache_get(ffffffff828d9a80) at pool_cache_get+0x323 sys/kern/subr_pool.c:1884 pool_get(ffffffff828d9a80,2) at pool_get+0x91 sys/kern/subr_pool.c:572 m_get(2,1) at m_get+0x4c sys/kern/uipc_mbuf.c:250 ip6_output(fffffd807cde3a00,ffffffff827bdb58,0,0,ffff800021eff238,0) at ip6_output+0x203 sys/netinet6/ip6_output.c:198 mld6_sendpkt(ffff800000aef680,84,ffffffff82726e00) at mld6_sendpkt+0x2da sys/netinet6/mld6.c:465 in6_delmulti(ffff800000aef680) at in6_delmulti+0xbb sys/netinet6/in6.c:1092 in6_purgeaddr(ffff800000b02600) at in6_purgeaddr+0x195 in6_leavegroup sys/netinet6/in6.c:1156 [inline] in6_purgeaddr(ffff800000b02600) at in6_purgeaddr+0x195 sys/netinet6/in6.c:925 in6_ioctl_change_ifaddr(8080691a,ffff800021eff660,ffff800000af5000) at in6_ioctl_change_ifaddr+0xa2f ifioctl(fffffd8065af4018,8080691a,ffff800021eff660,ffff800020e034f8) at ifioctl+0xe70 sys/net/if.c:2180 soo_ioctl(fffffd8066cf2ef8,8080691a,ffff800021eff660,ffff800020e034f8) at soo_ioctl+0x27c sys/kern/sys_socket.c:138 sys_ioctl(ffff800020e034f8,ffff800021eff778,ffff800021eff7c0) at sys_ioctl+0x4a5 syscall(ffff800021eff840) at syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff800021eff840) at syscall+0x4a4 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x8c89a365b20, count: -15 ddb{0}> machine ddbcpu 1