panic: kernel diagnostic assertion "refs != ~0" failed: file "/syzkaller/managers/multicore/kernel/sys/kern/kern_synch.c", line 955
Starting stack trace...
panic(ffffffff8344b92f) at panic+0x1d0 sys/kern/subr_prf.c:229
__assert(ffffffff834879a7,ffffffff83494155,3bb,ffffffff834bc7e9) at __assert+0x29 sys/kern/subr_prf.c:-1
refcnt_finalize(ffff80003c4334f0,ffffffff8344111b) at refcnt_finalize+0x1db sys/kern/kern_synch.c:956
pppx_if_destroy(ffff80002b7a0000,ffff80003c4334e8) at pppx_if_destroy+0x3d sys/net/if_pppx.c:794
pppxclose(205b9a,2,2000,ffff80003c49f790) at pppxclose+0xa0 sys/net/if_pppx.c:541
spec_close(ffff800033bb1150) at spec_close+0x417 sys/kern/spec_vnops.c:-1
VOP_CLOSE(fffffd805ed287a8,2,fffffd80097fd3a8,ffff80003c49f790) at VOP_CLOSE+0x132 sys/kern/vfs_vops.c:156
vn_closefile(fffffd806998aa60,ffff80003c49f790) at vn_closefile+0x12b vn_close sys/kern/vfs_vnops.c:292 [inline]
vn_closefile(fffffd806998aa60,ffff80003c49f790) at vn_closefile+0x12b sys/kern/vfs_vnops.c:615
fdrop(fffffd806998aa60,ffff80003c49f790) at fdrop+0x121 sys/kern/kern_descrip.c:1281
closef(fffffd806998aa60,ffff80003c49f790) at closef+0x192 sys/kern/kern_descrip.c:1265
syscall(ffff800033bb13b0) at syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline]
syscall(ffff800033bb13b0) at syscall+0xbd4 sys/arch/amd64/amd64/trap.c:783
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x723d41a4b60, count: 245
End of stack trace.
syncing disks...