panic: kernel diagnostic assertion "refs != ~0" failed: file "/syzkaller/managers/multicore/kernel/sys/kern/kern_synch.c", line 953 Starting stack trace... panic(ffffffff833943a7) at panic+0x1d0 sys/kern/subr_prf.c:229 __assert(ffffffff833d16ba,ffffffff833e4470,3b9,ffffffff8340e057) at __assert+0x29 sys/kern/subr_prf.c:-1 refcnt_finalize(ffff80002bfeef18,ffffffff83384e88) at refcnt_finalize+0x1db sys/kern/kern_synch.c:954 pppx_if_destroy(0,ffff80002bfeef10) at pppx_if_destroy+0x3d sys/net/if_pppx.c:794 pppxclose(285b9a,41,2000,ffff80003c40c2b8) at pppxclose+0xa0 sys/net/if_pppx.c:541 spec_close(ffff80003b3fd590) at spec_close+0x417 sys/kern/spec_vnops.c:-1 VOP_CLOSE(fffffd805b5fea80,41,fffffd80097fb478,ffff80003c40c2b8) at VOP_CLOSE+0x132 sys/kern/vfs_vops.c:156 vn_closefile(fffffd806aefbe18,ffff80003c40c2b8) at vn_closefile+0x12b vn_close sys/kern/vfs_vnops.c:292 [inline] vn_closefile(fffffd806aefbe18,ffff80003c40c2b8) at vn_closefile+0x12b sys/kern/vfs_vnops.c:615 fdrop(fffffd806aefbe18,ffff80003c40c2b8) at fdrop+0x121 sys/kern/kern_descrip.c:1280 closef(fffffd806aefbe18,ffff80003c40c2b8) at closef+0x192 sys/kern/kern_descrip.c:1264 fdfree(ffff80003c40c2b8) at fdfree+0x116 sys/kern/kern_descrip.c:1195 exit1(ffff80003c40c2b8,0,0,1) at exit1+0x576 sys/kern/kern_exit.c:215 sys_exit(ffff80003c40c2b8,ffff80003b3fd900,ffff80003b3fd850) at sys_exit+0x1a sys/kern/kern_exit.c:-1 syscall(ffff80003b3fd900) at syscall+0xb17 mi_syscall sys/sys/syscall_mi.h:176 [inline] syscall(ffff80003b3fd900) at syscall+0xb17 sys/arch/amd64/amd64/trap.c:765 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x762fa6a397b0, count: 242 End of stack trace.