Loading the following module results in a warning on
4.4.0-rc4-1.g923c13b-vanilla but not on 4.4.0-rc4-1.g923c13b-default.

dmesg:
[   62.421172] init_module()
[   62.421187] ------------[ cut here ]------------
[   62.421202] WARNING: CPU: 0 PID: 1939 at ../kernel/module.c:1124
module_put+0xac/0xc0()
[   62.421205] Modules linked in: h(O) xfs libcrc32c dm_mod irda crc_ccitt
sr_mod cdrom ata_generic vmw_balloon ppdev joydev floppy e1000 pcspkr
8250_fintek fjes parport_pc parport ata_piix shpchp i2c_piix4 acpi_cpufreq
vmw_vmci battery mptctl ac tpm_tis tpm button sg vmwgfx mptspi mptscsih mptbase
scsi_transport_spi ttm drm_kms_helper drm fb_sys_fops sysimgblt sysfillrect
syscopyarea scsi_dh_alua scsi_dh_emc scsi_dh_rdac scsi_dh_hp_sw
[   62.421267] CPU: 0 PID: 1939 Comm: insmod Tainted: G           O   
4.4.0-rc4-1.g923c13b-vanilla #1
[   62.421272] Hardware name: VMware, Inc. VMware Virtual Platform/440BX
Desktop Reference Platform, BIOS 6.00 07/02/2012
[   62.421276]  ffffffff81a5cee9 ffff88003721fcc8 ffffffff8137ada9
0000000000000000
[   62.421283]  ffff88003721fd00 ffffffff8107c1f2 ffffffffa0289000
ffffffffa0289000
[   62.421288]  ffff880037219600 0000000000000001 ffffffffa0289000
ffff88003721fd10
[   62.421293] Call Trace:
[   62.421309]  [<ffffffff8137ada9>] dump_stack+0x4b/0x72
[   62.421320]  [<ffffffff8107c1f2>] warn_slowpath_common+0x82/0xc0
[   62.421328]  [<ffffffff8107c2ea>] warn_slowpath_null+0x1a/0x20
[   62.421334]  [<ffffffff810fd52c>] module_put+0xac/0xc0
[   62.421345]  [<ffffffff811810d7>] do_init_module+0xd5/0x1e5
[   62.421352]  [<ffffffff81101f99>] load_module+0x15d9/0x1b30
[   62.421359]  [<ffffffff810fe190>] ? __symbol_put+0x50/0x50
[   62.421369]  [<ffffffff81102615>] SyS_init_module+0x125/0x160
[   62.421380]  [<ffffffff816a4db6>] entry_SYSCALL_64_fastpath+0x16/0x75
[   62.421385] ---[ end trace 5e2217ea63923545 ]---

module:
#include <linux/module.h>
#include <linux/kernel.h>

int init_module(void)
{
        printk(KERN_INFO "init_module()\n");
        return 0;
}

void cleanup_module(void)
{
        printk(KERN_INFO "cleanup_module()\n");
}

MODULE_LICENSE("GPL");