panic: kernel diagnostic assertion "refs != ~0" failed: file "/syzkaller/managers/main/kernel/sys/kern/kern_synch.c", line 951
Starting stack trace...
panic(ffffffff834344cb) at panic+0x1ba sys/kern/subr_prf.c:229
__assert(ffffffff833e420a,ffffffff83330599,3b7,ffffffff833e94fd) at __assert+0x29 sys/kern/subr_prf.c:-1
refcnt_finalize(ffff80002a8aeb50,ffffffff8333293b) at refcnt_finalize+0x1c8 sys/kern/kern_synch.c:952
pppx_if_destroy(205b9a,ffff80002a8aeb48) at pppx_if_destroy+0x3d sys/net/if_pppx.c:794
pppxclose(205b9a,1,2000,ffff80002a880558) at pppxclose+0xa0 sys/net/if_pppx.c:541
spec_close(ffff800033545bb0) at spec_close+0x412 sys/kern/spec_vnops.c:-1
VOP_CLOSE(fffffd8068b7fdb8,1,fffffd8007bfb888,ffff80002a880558) at VOP_CLOSE+0x12a sys/kern/vfs_vops.c:156
vn_closefile(fffffd8069120c30,ffff80002a880558) at vn_closefile+0x11d vn_close sys/kern/vfs_vnops.c:292 [inline]
vn_closefile(fffffd8069120c30,ffff80002a880558) at vn_closefile+0x11d sys/kern/vfs_vnops.c:615
fdrop(fffffd8069120c30,ffff80002a880558) at fdrop+0x126 sys/kern/kern_descrip.c:1267
closef(fffffd8069120c30,ffff80002a880558) at closef+0x190 sys/kern/kern_descrip.c:1251
fdfree(ffff80002a880558) at fdfree+0x115 sys/kern/kern_descrip.c:1182
exit1(ffff80002a880558,0,0,1) at exit1+0x59c sys/kern/kern_exit.c:215
sys_exit(ffff80002a880558,ffff800033545f20,ffff800033545e70) at sys_exit+0x1a sys/kern/kern_exit.c:-1
syscall(ffff800033545f20) at syscall+0x97e mi_syscall sys/sys/syscall_mi.h:-1 [inline]
syscall(ffff800033545f20) at syscall+0x97e sys/arch/amd64/amd64/trap.c:748
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x73066bea6430, count: 242
End of stack trace.