staging: rtl8712: fix uninit-value in r871xu_drv_init()

[ Upstream commit 0458e542 ]

When 'tmpU1b' returns from r8712_read8(padapter, EE_9346CR) is 0,
'mac[6]' will not be initialized.

BUG: KMSAN: uninit-value in r871xu_drv_init+0x2d54/0x3070 drivers/staging/rtl8712/usb_intf.c:541
 r871xu_drv_init+0x2d54/0x3070 drivers/staging/rtl8712/usb_intf.c:541
 usb_probe_interface+0xf19/0x1600 drivers/usb/core/driver.c:396
 really_probe+0x653/0x14b0 drivers/base/dd.c:596
 __driver_probe_device+0x3e9/0x530 drivers/base/dd.c:752
 driver_probe_device drivers/base/dd.c:782 [inline]
 __device_attach_driver+0x79f/0x1120 drivers/base/dd.c:899
 bus_for_each_drv+0x2d6/0x3f0 drivers/base/bus.c:427
 __device_attach+0x593/0x8e0 drivers/base/dd.c:970
 device_initial_probe+0x4a/0x60 drivers/base/dd.c:1017
 bus_probe_device+0x17b/0x3e0 drivers/base/bus.c:487
 device_add+0x1fff/0x26e0 drivers/base/core.c:3405
 usb_set_configuration+0x37e9/0x3ed0 drivers/usb/core/message.c:2170
 usb_generic_driver_probe+0x13c/0x300 drivers/usb/core/generic.c:238
 usb_probe_device+0x309/0x570 drivers/usb/core/driver.c:293
 really_probe+0x653/0x14b0 drivers/base/dd.c:596
 __driver_probe_device+0x3e9/0x530 drivers/base/dd.c:752
 driver_probe_device drivers/base/dd.c:782 [inline]
 __device_attach_driver+0x79f/0x1120 drivers/base/dd.c:899
 bus_for_each_drv+0x2d6/0x3f0 drivers/base/bus.c:427
 __device_attach+0x593/0x8e0 drivers/base/dd.c:970
 device_initial_probe+0x4a/0x60 drivers/base/dd.c:1017
 bus_probe_device+0x17b/0x3e0 drivers/base/bus.c:487
 device_add+0x1fff/0x26e0 drivers/base/core.c:3405
 usb_new_device+0x1b8e/0x2950 drivers/usb/core/hub.c:2566
 hub_port_connect drivers/usb/core/hub.c:5358 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5502 [inline]
 port_event drivers/usb/core/hub.c:5660 [inline]
 hub_event+0x58e3/0x89e0 drivers/usb/core/hub.c:5742
 process_one_work+0xdb6/0x1820 kernel/workqueue.c:2307
 worker_thread+0x10b3/0x21e0 kernel/workqueue.c:2454
 kthread+0x3c7/0x500 kernel/kthread.c:377
 ret_from_fork+0x1f/0x30

Local variable mac created at:
 r871xu_drv_init+0x1771/0x3070 drivers/staging/rtl8712/usb_intf.c:394
 usb_probe_interface+0xf19/0x1600 drivers/usb/core/driver.c:396

KMSAN: uninit-value in r871xu_drv_init
https://syzkaller.appspot.com/bug?id=3cd92b1d85428b128503bfa7a250294c9ae00bd8



Reported-by:  <syzbot+6f5ecd144854c0d8580b@syzkaller.appspotmail.com>
Tested-by:  <syzbot+6f5ecd144854c0d8580b@syzkaller.appspotmail.com>
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Wang Cheng <wanngchenng@gmail.com>
Link: https://lore.kernel.org/r/14c3886173dfa4597f0704547c414cfdbcd11d16.1652618244.git.wanngchenng@gmail.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>