panic: kernel diagnostic assertion "ps->ps_uvncount == 0" failed: file "/syzkaller/managers/multicore/kernel/sys/kern/kern_unveil.c", line 188
Stopped at      db_enter+0x1c:  addq    $0x8,%rsp
    TID    PID    UID     PRFLAGS     PFLAGS  CPU  COMMAND
 155793  17707      0         0x2        0x1    1  syz-executor.5
db_enter() at db_enter+0x1c sys/arch/amd64/amd64/db_interface.c:437
panic(ffffffff827a0e01) at panic+0x17b sys/kern/subr_prf.c:198
__assert(ffffffff8281f100,ffffffff82823261,bc,ffffffff827b914b) at __assert+0x29 sys/kern/subr_prf.c:157
unveil_destroy(ffff8000ffff6e30) at unveil_destroy+0x1a4 sys/kern/kern_unveil.c:188
exit1(ffff8000212b2b10,0,0,1) at exit1+0x3d5 sys/kern/kern_exit.c:220
sys_exit(ffff8000212b2b10,ffff80002633ef30,ffff80002633ef80) at sys_exit+0x1a sys/kern/kern_exit.c:89
syscall(ffff80002633f000) at syscall+0x5e2 mi_syscall sys/sys/syscall_mi.h:110 [inline]
syscall(ffff80002633f000) at syscall+0x5e2 sys/arch/amd64/amd64/trap.c:623
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x75f295eb57c0, count: 7
https://www.openbsd.org/ddb.html describes the minimum info required in bug
reports.  Insufficient info makes it difficult to find and fix bugs.