panic: kernel diagnostic assertion "refs != ~0" failed: file "/syzkaller/managers/multicore/kernel/sys/kern/kern_synch.c", line 959
Starting stack trace...
panic(ffffffff834bec20) at panic+0x1d0 sys/kern/subr_prf.c:229
__assert(ffffffff834fb934,ffffffff8350b6af,3bf,ffffffff8353439c) at __assert+0x29 sys/kern/subr_prf.c:-1
refcnt_finalize(ffff80003bbbf148,ffffffff834b1125) at refcnt_finalize+0x1e7 sys/kern/kern_synch.c:960
pppx_if_destroy(ffff800037fa4000,ffff80003bbbf140) at pppx_if_destroy+0x3d sys/net/if_pppx.c:794
pppxclose(205b9a,81,2000,ffff80003abb8a80) at pppxclose+0xa0 sys/net/if_pppx.c:541
spec_close(ffff80002a282440) at spec_close+0x417 sys/kern/spec_vnops.c:-1
VOP_CLOSE(fffff10077e70b38,81,fffff100097fd548,ffff80003abb8a80) at VOP_CLOSE+0x132 sys/kern/vfs_vops.c:156
vn_closefile(fffff1006fda7148,ffff80003abb8a80) at vn_closefile+0x12b vn_close sys/kern/vfs_vnops.c:298 [inline]
vn_closefile(fffff1006fda7148,ffff80003abb8a80) at vn_closefile+0x12b sys/kern/vfs_vnops.c:621
fdrop(fffff1006fda7148,ffff80003abb8a80) at fdrop+0x121 sys/kern/kern_descrip.c:1281
closef(fffff1006fda7148,ffff80003abb8a80) at closef+0x192 sys/kern/kern_descrip.c:1265
sys_closefrom(ffff80003abb8a80,ffff80002a282710,ffff80002a282660) at sys_closefrom+0x13c sys/kern/kern_descrip.c:1471
syscall(ffff80002a282710) at syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline]
syscall(ffff80002a282710) at syscall+0xbd4 sys/arch/amd64/amd64/trap.c:783
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x69ca3f11fc0, count: 244
End of stack trace.
syncing disks...