panic: kernel diagnostic assertion "refs != ~0" failed: file "/syzkaller/managers/main/kernel/sys/kern/kern_synch.c", line 955
Starting stack trace...
panic(ffffffff83377ffc) at panic+0x1ba sys/kern/subr_prf.c:229
__assert(ffffffff833ba1e7,ffffffff8341b486,3bb,ffffffff833f4c7d) at __assert+0x29 sys/kern/subr_prf.c:-1
refcnt_finalize(ffff80003c93cae0,ffffffff8336edb3) at refcnt_finalize+0x1c8 sys/kern/kern_synch.c:956
pppx_if_destroy(205b92,ffff80003c93cad8) at pppx_if_destroy+0x3d sys/net/if_pppx.c:794
pppxclose(205b92,81,2000,ffff80002a802800) at pppxclose+0xa0 sys/net/if_pppx.c:541
spec_close(ffff80002a82b9a0) at spec_close+0x417 sys/kern/spec_vnops.c:-1
VOP_CLOSE(fffffd80666f67e0,81,fffffd8007bfd820,ffff80002a802800) at VOP_CLOSE+0x129 sys/kern/vfs_vops.c:156
vn_closefile(fffffd80691cb4c0,ffff80002a802800) at vn_closefile+0x11d vn_close sys/kern/vfs_vnops.c:292 [inline]
vn_closefile(fffffd80691cb4c0,ffff80002a802800) at vn_closefile+0x11d sys/kern/vfs_vnops.c:615
fdrop(fffffd80691cb4c0,ffff80002a802800) at fdrop+0x121 sys/kern/kern_descrip.c:1280
closef(fffffd80691cb4c0,ffff80002a802800) at closef+0x190 sys/kern/kern_descrip.c:1264
fdfree(ffff80002a802800) at fdfree+0x115 sys/kern/kern_descrip.c:1195
exit1(ffff80002a802800,b,0,1) at exit1+0x576 sys/kern/kern_exit.c:215
sys_exit(ffff80002a802800,ffff80002a82bd00,ffff80002a82bc50) at sys_exit+0x1a sys/kern/kern_exit.c:-1
syscall(ffff80002a82bd00) at syscall+0x962 mi_syscall sys/sys/syscall_mi.h:-1 [inline]
syscall(ffff80002a82bd00) at syscall+0x962 sys/arch/amd64/amd64/trap.c:775
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x767da01a2a50, count: 242
End of stack trace.