panic: kernel diagnostic assertion "refs != ~0" failed: file "/syzkaller/managers/main/kernel/sys/kern/kern_synch.c", line 953 Starting stack trace... panic(ffffffff83361bd1) at panic+0x1ba sys/kern/subr_prf.c:229 __assert(ffffffff8339cfcd,ffffffff833ff675,3b9,ffffffff833d981e) at __assert+0x29 sys/kern/subr_prf.c:-1 refcnt_finalize(ffff80002a8ce080,ffffffff83359354) at refcnt_finalize+0x1c8 sys/kern/kern_synch.c:954 pppx_if_destroy(285b9a,ffff80002a8ce078) at pppx_if_destroy+0x3d sys/net/if_pppx.c:794 pppxclose(285b9a,1,2000,ffff80003c94a550) at pppxclose+0xa0 sys/net/if_pppx.c:541 spec_close(ffff80003c962da0) at spec_close+0x417 sys/kern/spec_vnops.c:-1 VOP_CLOSE(fffffd806b739880,1,fffffd8007bfb208,ffff80003c94a550) at VOP_CLOSE+0x129 sys/kern/vfs_vops.c:156 vn_closefile(fffffd806c51d810,ffff80003c94a550) at vn_closefile+0x11d vn_close sys/kern/vfs_vnops.c:292 [inline] vn_closefile(fffffd806c51d810,ffff80003c94a550) at vn_closefile+0x11d sys/kern/vfs_vnops.c:615 fdrop(fffffd806c51d810,ffff80003c94a550) at fdrop+0x121 sys/kern/kern_descrip.c:1280 closef(fffffd806c51d810,ffff80003c94a550) at closef+0x190 sys/kern/kern_descrip.c:1264 fdfree(ffff80003c94a550) at fdfree+0x115 sys/kern/kern_descrip.c:1195 exit1(ffff80003c94a550,0,0,1) at exit1+0x576 sys/kern/kern_exit.c:215 sys_exit(ffff80003c94a550,ffff80003c963100,ffff80003c963050) at sys_exit+0x1a sys/kern/kern_exit.c:-1 syscall(ffff80003c963100) at syscall+0x962 mi_syscall sys/sys/syscall_mi.h:-1 [inline] syscall(ffff80003c963100) at syscall+0x962 sys/arch/amd64/amd64/trap.c:765 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x6fcf1ea47320, count: 242 End of stack trace.