panic: kernel diagnostic assertion "refs != ~0" failed: file "/syzkaller/managers/multicore/kernel/sys/kern/kern_synch.c", line 944
Starting stack trace...
panic(ffffffff8343fe55) at panic+0x1d0 sys/kern/subr_prf.c:229
__assert(ffffffff833ea525,ffffffff833eea67,3b0,ffffffff833eeaaf) at __assert+0x29
refcnt_finalize(ffff80002a3fb9a8,ffffffff8332f76d) at refcnt_finalize+0x1c8 sys/kern/kern_synch.c:945
pppx_if_destroy(ffff80003a0c0000,ffff80002a3fb9a0) at pppx_if_destroy+0x3d sys/net/if_pppx.c:806
pppxclose(205b9a,1,2000,ffff80003c51c548) at pppxclose+0xa0 sys/net/if_pppx.c:553
spec_close(ffff80003c4d8b30) at spec_close+0x412
VOP_CLOSE(fffffd8075506138,1,fffffd807f7d2270,ffff80003c51c548) at VOP_CLOSE+0x133 sys/kern/vfs_vops.c:156
vn_closefile(fffffd806cf9d148,ffff80003c51c548) at vn_closefile+0x12b vn_close sys/kern/vfs_vnops.c:292 [inline]
vn_closefile(fffffd806cf9d148,ffff80003c51c548) at vn_closefile+0x12b sys/kern/vfs_vnops.c:615
fdrop(fffffd806cf9d148,ffff80003c51c548) at fdrop+0x126 sys/kern/kern_descrip.c:1265
closef(fffffd806cf9d148,ffff80003c51c548) at closef+0x192 sys/kern/kern_descrip.c:1249
finishdup(ffff80003c51c548,fffffd806cf9d3a8,6,5,ffff80003c4d8da0,2) at finishdup+0x444 sys/kern/kern_descrip.c:677
syscall(ffff80003c4d8e50) at syscall+0xbc6 mi_syscall sys/sys/syscall_mi.h:176 [inline]
syscall(ffff80003c4d8e50) at syscall+0xbc6 sys/arch/amd64/amd64/trap.c:577
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x34f6c270a80, count: 244
End of stack trace.