panic: kernel diagnostic assertion "refs != ~0" failed: file "/syzkaller/managers/main/kernel/sys/kern/kern_synch.c", line 944
Starting stack trace...
panic(ffffffff834040bd) at panic+0x1ba sys/kern/subr_prf.c:229
__assert(ffffffff833b33c4,ffffffff8330351e,3b0,ffffffff833bc77e) at __assert+0x29
refcnt_finalize(ffff80002a7c75d0,ffffffff832ffb59) at refcnt_finalize+0x1c8 sys/kern/kern_synch.c:945
pppx_if_destroy(0,ffff80002a7c75c8) at pppx_if_destroy+0x3d sys/net/if_pppx.c:806
pppxclose(205b9a,1,2000,ffff80002cd0aa68) at pppxclose+0xa0 sys/net/if_pppx.c:553
spec_close(ffff80003c9bec30) at spec_close+0x412
VOP_CLOSE(fffffd8066a1e8c8,1,fffffd807f7d77b8,ffff80002cd0aa68) at VOP_CLOSE+0x12a sys/kern/vfs_vops.c:156
vn_closefile(fffffd8065e60528,ffff80002cd0aa68) at vn_closefile+0x11d vn_close sys/kern/vfs_vnops.c:292 [inline]
vn_closefile(fffffd8065e60528,ffff80002cd0aa68) at vn_closefile+0x11d sys/kern/vfs_vnops.c:615
fdrop(fffffd8065e60528,ffff80002cd0aa68) at fdrop+0x126 sys/kern/kern_descrip.c:1265
closef(fffffd8065e60528,ffff80002cd0aa68) at closef+0x18d sys/kern/kern_descrip.c:1249
fdfree(ffff80002cd0aa68) at fdfree+0x115 sys/kern/kern_descrip.c:1181
exit1(ffff80002cd0aa68,0,0,1) at exit1+0x57f sys/kern/kern_exit.c:214
sys_exit(ffff80002cd0aa68,ffff80003c9befa0,ffff80003c9beef0) at sys_exit+0x1a
syscall(ffff80003c9befa0) at syscall+0x97e sys/arch/amd64/amd64/trap.c:577
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x7ec578863ff0, count: 242
End of stack trace.