panic: kernel diagnostic assertion "refs != ~0" failed: file "/syzkaller/managers/main/kernel/sys/kern/kern_synch.c", line 951
Starting stack trace...
panic(ffffffff83338a99) at panic+0x1ba sys/kern/subr_prf.c:229
__assert(ffffffff8337a1de,ffffffff833d50c4,3b7,ffffffff833aed65) at __assert+0x29 sys/kern/subr_prf.c:-1
refcnt_finalize(ffff80003ca57620,ffffffff8332fd8b) at refcnt_finalize+0x1c8 sys/kern/kern_synch.c:952
pppx_if_destroy(285b9a,ffff80003ca57618) at pppx_if_destroy+0x3d sys/net/if_pppx.c:794
pppxclose(285b9a,1,2000,ffff80002a924038) at pppxclose+0xa0 sys/net/if_pppx.c:541
spec_close(ffff800033d53b30) at spec_close+0x417 sys/kern/spec_vnops.c:-1
VOP_CLOSE(fffffd8067bda018,1,fffffd8007bfb750,ffff80002a924038) at VOP_CLOSE+0x129 sys/kern/vfs_vops.c:156
vn_closefile(fffffd80695a6178,ffff80002a924038) at vn_closefile+0x11d vn_close sys/kern/vfs_vnops.c:292 [inline]
vn_closefile(fffffd80695a6178,ffff80002a924038) at vn_closefile+0x11d sys/kern/vfs_vnops.c:615
fdrop(fffffd80695a6178,ffff80002a924038) at fdrop+0x121 sys/kern/kern_descrip.c:1280
closef(fffffd80695a6178,ffff80002a924038) at closef+0x190 sys/kern/kern_descrip.c:1264
fdfree(ffff80002a924038) at fdfree+0x115 sys/kern/kern_descrip.c:1195
exit1(ffff80002a924038,0,0,1) at exit1+0x576 sys/kern/kern_exit.c:215
sys_exit(ffff80002a924038,ffff800033d53e90,ffff800033d53de0) at sys_exit+0x1a sys/kern/kern_exit.c:-1
syscall(ffff800033d53e90) at syscall+0x962 mi_syscall sys/sys/syscall_mi.h:-1 [inline]
syscall(ffff800033d53e90) at syscall+0x962 sys/arch/amd64/amd64/trap.c:748
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x7f1f1ba6e5f0, count: 242
End of stack trace.