panic: kernel diagnostic assertion "refs != ~0" failed: file "/syzkaller/managers/multicore/kernel/sys/kern/kern_synch.c", line 944
Starting stack trace...
panic(ffffffff8343c78e) at panic+0x1d0 sys/kern/subr_prf.c:229
__assert(ffffffff833e97ac,ffffffff833efe28,3b0,ffffffff833efe70) at __assert+0x29
refcnt_finalize(ffff80002a4539d0,ffffffff8332e326) at refcnt_finalize+0x1c8 sys/kern/kern_synch.c:945
pppx_if_destroy(205b9a,ffff80002a4539c8) at pppx_if_destroy+0x3d sys/net/if_pppx.c:806
pppxclose(205b9a,1,2000,ffff8000ffff59d0) at pppxclose+0xa0 sys/net/if_pppx.c:553
spec_close(ffff80002a45f0a0) at spec_close+0x412
VOP_CLOSE(fffffd805c466d90,1,fffffd807f7d3680,ffff8000ffff59d0) at VOP_CLOSE+0x133 sys/kern/vfs_vops.c:156
vn_closefile(fffffd806be88998,ffff8000ffff59d0) at vn_closefile+0x12b vn_close sys/kern/vfs_vnops.c:292 [inline]
vn_closefile(fffffd806be88998,ffff8000ffff59d0) at vn_closefile+0x12b sys/kern/vfs_vnops.c:615
fdrop(fffffd806be88998,ffff8000ffff59d0) at fdrop+0x126 sys/kern/kern_descrip.c:1265
closef(fffffd806be88998,ffff8000ffff59d0) at closef+0x192 sys/kern/kern_descrip.c:1249
syscall(ffff80002a45f300) at syscall+0xbc6 mi_syscall sys/sys/syscall_mi.h:176 [inline]
syscall(ffff80002a45f300) at syscall+0xbc6 sys/arch/amd64/amd64/trap.c:577
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0xaec9511fd30, count: 245
End of stack trace.