panic: kernel diagnostic assertion "refs != ~0" failed: file "/syzkaller/managers/main/kernel/sys/kern/kern_synch.c", line 953
Starting stack trace...
panic(ffffffff83337890) at panic+0x1ba sys/kern/subr_prf.c:229
__assert(ffffffff83379b84,ffffffff833d30d2,3b9,ffffffff833ac817) at __assert+0x29 sys/kern/subr_prf.c:-1
refcnt_finalize(ffff80002a83f630,ffffffff83334d46) at refcnt_finalize+0x1c8 sys/kern/kern_synch.c:954
pppx_if_destroy(205b9a,ffff80002a83f628) at pppx_if_destroy+0x3d sys/net/if_pppx.c:794
pppxclose(205b9a,2,2000,ffff80002d524560) at pppxclose+0xa0 sys/net/if_pppx.c:541
spec_close(ffff80003c975be0) at spec_close+0x417 sys/kern/spec_vnops.c:-1
VOP_CLOSE(fffffd806e8a57f0,2,fffffd8007bfb888,ffff80002d524560) at VOP_CLOSE+0x129 sys/kern/vfs_vops.c:156
vn_closefile(fffffd807761c888,ffff80002d524560) at vn_closefile+0x11d vn_close sys/kern/vfs_vnops.c:292 [inline]
vn_closefile(fffffd807761c888,ffff80002d524560) at vn_closefile+0x11d sys/kern/vfs_vnops.c:615
fdrop(fffffd807761c888,ffff80002d524560) at fdrop+0x121 sys/kern/kern_descrip.c:1280
closef(fffffd807761c888,ffff80002d524560) at closef+0x190 sys/kern/kern_descrip.c:1264
fdfree(ffff80002d524560) at fdfree+0x115 sys/kern/kern_descrip.c:1195
exit1(ffff80002d524560,0,0,3) at exit1+0x576 sys/kern/kern_exit.c:215
proc_suspend_check_locked(ffff80002d524560,0) at proc_suspend_check_locked+0x45a sys/kern/kern_sig.c:2235
userret(ffff80002d524560) at userret+0x8c proc_suspend_check sys/kern/kern_sig.c:-1 [inline]
userret(ffff80002d524560) at userret+0x8c sys/kern/kern_sig.c:2194
intr_user_exit() at intr_user_exit+0x3c
end of kernel
end trace frame: 0x72a5718dd470, count: 242
End of stack trace.