panic: kernel diagnostic assertion "refs != ~0" failed: file "/syzkaller/managers/main/kernel/sys/kern/kern_synch.c", line 944
Starting stack trace...
panic(ffffffff83408af9) at panic+0x1ba sys/kern/subr_prf.c:229
__assert(ffffffff833b4574,ffffffff832fd646,3b0,ffffffff833b636d) at __assert+0x29
refcnt_finalize(ffff80003c99f070,ffffffff832feefd) at refcnt_finalize+0x1c8 sys/kern/kern_synch.c:945
pppx_if_destroy(ffff80002ad08000,ffff80003c99f068) at pppx_if_destroy+0x3d sys/net/if_pppx.c:806
pppxclose(205b9a,1,2000,ffff80003c98c030) at pppxclose+0xa0 sys/net/if_pppx.c:553
spec_close(ffff80003ca02d40) at spec_close+0x412
VOP_CLOSE(fffffd806a35f440,1,fffffd807f7d76e8,ffff80003c98c030) at VOP_CLOSE+0x12a sys/kern/vfs_vops.c:156
vn_closefile(fffffd806ad8cda0,ffff80003c98c030) at vn_closefile+0x11d vn_close sys/kern/vfs_vnops.c:292 [inline]
vn_closefile(fffffd806ad8cda0,ffff80003c98c030) at vn_closefile+0x11d sys/kern/vfs_vnops.c:615
fdrop(fffffd806ad8cda0,ffff80003c98c030) at fdrop+0x126 sys/kern/kern_descrip.c:1265
closef(fffffd806ad8cda0,ffff80003c98c030) at closef+0x18d sys/kern/kern_descrip.c:1249
syscall(ffff80003ca02fa0) at syscall+0x97e sys/arch/amd64/amd64/trap.c:577
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x8a4c4d1b5b0, count: 245
End of stack trace.