panic: kernel diagnostic assertion "refs != ~0" failed: file "/syzkaller/managers/multicore/kernel/sys/kern/kern_synch.c", line 955
Stopped at      db_enter+0x25:  addq    $0x8,%rsp
    TID    PID    UID     PRFLAGS     PFLAGS  CPU  COMMAND
 229955  63718      0           0          0    0  syz-executor
db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:438
panic(ffffffff834be690) at panic+0x1e5 sys/kern/subr_prf.c:198
__assert(ffffffff834f96fd,ffffffff83506fac,3bb,ffffffff8352fd64) at __assert+0x29 sys/kern/subr_prf.c:-1
refcnt_finalize(ffff80002a243150,ffffffff834ade6a) at refcnt_finalize+0x1db sys/kern/kern_synch.c:956
pppx_if_destroy(285b9e,ffff80002a243148) at pppx_if_destroy+0x3d sys/net/if_pppx.c:794
pppxclose(285b9e,41,2000,ffff800030f84fb8) at pppxclose+0xa0 sys/net/if_pppx.c:541
spec_close(ffff80002a260900) at spec_close+0x417 sys/kern/spec_vnops.c:-1
VOP_CLOSE(fffff4806ea96210,41,fffff480097fd618,ffff800030f84fb8) at VOP_CLOSE+0x132 sys/kern/vfs_vops.c:156
vn_closefile(fffff4806f313d28,ffff800030f84fb8) at vn_closefile+0x12b vn_close sys/kern/vfs_vnops.c:298 [inline]
vn_closefile(fffff4806f313d28,ffff800030f84fb8) at vn_closefile+0x12b sys/kern/vfs_vnops.c:621
fdrop(fffff4806f313d28,ffff800030f84fb8) at fdrop+0x121 sys/kern/kern_descrip.c:1281
closef(fffff4806f313d28,ffff800030f84fb8) at closef+0x192 sys/kern/kern_descrip.c:1265
fdfree(ffff800030f84fb8) at fdfree+0x116 sys/kern/kern_descrip.c:1196
exit1(ffff800030f84fb8,0,0,1) at exit1+0x576 sys/kern/kern_exit.c:215
sys_exit(ffff800030f84fb8,ffff80002a260c70,ffff80002a260bc0) at sys_exit+0x1a sys/kern/kern_exit.c:-1
end trace frame: 0xffff80002a260c60, count: 0
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