panic: malloc: allocation too large, type = 2, size = 18446744073709551296

Stopped at      db_enter+0x18:  addq    $0x8,%rsp
    TID    PID    UID     PRFLAGS     PFLAGS  CPU  COMMAND
*351307  61579      0           0  0x4000000    0  syz-executor.0
db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398
panic() at panic+0x15c sys/kern/subr_prf.c:207
malloc(fffffffffffffec0,2,a) at malloc+0x9c9 sys/kern/kern_malloc.c:344
vm_get_info(ffff800015920a50) at vm_get_info+0x9a
VOP_IOCTL(fffffd803d0684c0,c0185603,ffff800015920a50,41,fffffd803f7c6840,ffff8000ffff2290) at VOP_IOCTL+0x88 sys/kern/vfs_vops.c:290
vn_ioctl(fffffd803c5fce10,c0185603,ffff800015920a50,ffff8000ffff2290) at vn_ioctl+0xb7 sys/kern/vfs_vnops.c:524
sys_ioctl(ffff8000ffff2290,ffff800015920b68,ffff800015920bd0) at sys_ioctl+0x5b8
syscall(ffff800015920c30) at syscall+0x508
Xsyscall(0,0,ffffffffffffff53,0,3,212552dd010) at Xsyscall+0x128
end of kernel
end trace frame: 0x214dd0d87e0, count: 6
https://www.openbsd.org/ddb.html describes the minimum info required in bug
reports.  Insufficient info makes it difficult to find and fix bugs.