KMSAN: uninit-value in smsc75xx_read

KMSAN: uninit-value in smsc75xx_read_eeprom (2)
Status: upstream: reported on 2020/12/09 09:03
Reported-by: syzbot+341170ccba949fac01a2@syzkaller.appspotmail.com
First crash: 128d, last: 99d

similar bugs (1):
Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KMSAN: uninit-value in smsc75xx_read_eeprom				10	576d	629d	0/22	auto-closed as invalid on 2019/12/15 14:14

Sample crash report:

=====================================================
BUG: KMSAN: uninit-value in smsc75xx_eeprom_confirm_not_busy drivers/net/usb/smsc75xx.c:333 [inline]
BUG: KMSAN: uninit-value in smsc75xx_read_eeprom+0x266/0xa10 drivers/net/usb/smsc75xx.c:352
CPU: 0 PID: 8477 Comm: kworker/0:3 Not tainted 5.10.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: usb_hub_wq hub_event
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x21c/0x280 lib/dump_stack.c:118
 kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:118
 __msan_warning+0x5f/0xa0 mm/kmsan/kmsan_instr.c:197
 smsc75xx_eeprom_confirm_not_busy drivers/net/usb/smsc75xx.c:333 [inline]
 smsc75xx_read_eeprom+0x266/0xa10 drivers/net/usb/smsc75xx.c:352
 smsc75xx_init_mac_address drivers/net/usb/smsc75xx.c:771 [inline]
 smsc75xx_bind+0xc71/0x13f0 drivers/net/usb/smsc75xx.c:1489
 usbnet_probe+0x1169/0x3e90 drivers/net/usb/usbnet.c:1712
 usb_probe_interface+0xfcc/0x1520 drivers/usb/core/driver.c:396
 really_probe+0xebd/0x2420 drivers/base/dd.c:558
 driver_probe_device+0x293/0x390 drivers/base/dd.c:738
 __device_attach_driver+0x63f/0x830 drivers/base/dd.c:844
 bus_for_each_drv+0x2ca/0x3f0 drivers/base/bus.c:431
 __device_attach+0x538/0x860 drivers/base/dd.c:912
 device_initial_probe+0x4a/0x60 drivers/base/dd.c:959
 bus_probe_device+0x177/0x3d0 drivers/base/bus.c:491
 device_add+0x399e/0x3f20 drivers/base/core.c:2936
 usb_set_configuration+0x39cf/0x4010 drivers/usb/core/message.c:2159
 usb_generic_driver_probe+0x138/0x300 drivers/usb/core/generic.c:238
 usb_probe_device+0x317/0x570 drivers/usb/core/driver.c:293
 really_probe+0xebd/0x2420 drivers/base/dd.c:558
 driver_probe_device+0x293/0x390 drivers/base/dd.c:738
 __device_attach_driver+0x63f/0x830 drivers/base/dd.c:844
 bus_for_each_drv+0x2ca/0x3f0 drivers/base/bus.c:431
 __device_attach+0x538/0x860 drivers/base/dd.c:912
 device_initial_probe+0x4a/0x60 drivers/base/dd.c:959
 bus_probe_device+0x177/0x3d0 drivers/base/bus.c:491
 device_add+0x399e/0x3f20 drivers/base/core.c:2936
 usb_new_device+0x1bd6/0x2a30 drivers/usb/core/hub.c:2554
 hub_port_connect drivers/usb/core/hub.c:5222 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5362 [inline]
 port_event drivers/usb/core/hub.c:5508 [inline]
 hub_event+0x5bc9/0x8890 drivers/usb/core/hub.c:5590
 process_one_work+0x121c/0x1fc0 kernel/workqueue.c:2272
 worker_thread+0x10cc/0x2740 kernel/workqueue.c:2418
 kthread+0x51c/0x560 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

Local variable ----buf.i.i92@smsc75xx_read_eeprom created at:
 __smsc75xx_read_reg drivers/net/usb/smsc75xx.c:322 [inline]
 smsc75xx_read_reg drivers/net/usb/smsc75xx.c:147 [inline]
 smsc75xx_eeprom_confirm_not_busy drivers/net/usb/smsc75xx.c:327 [inline]
 smsc75xx_read_eeprom+0x124/0xa10 drivers/net/usb/smsc75xx.c:352
 __smsc75xx_read_reg drivers/net/usb/smsc75xx.c:322 [inline]
 smsc75xx_read_reg drivers/net/usb/smsc75xx.c:147 [inline]
 smsc75xx_eeprom_confirm_not_busy drivers/net/usb/smsc75xx.c:327 [inline]
 smsc75xx_read_eeprom+0x124/0xa10 drivers/net/usb/smsc75xx.c:352
=====================================================

Crashes (4):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	VM info
ci-upstream-kmsan-gce	2021/01/05 20:49	https://github.com/google/kmsan.git master	73d62e81	a0234d98	.config	log	report	info
ci-upstream-kmsan-gce	2020/12/08 06:05	https://github.com/google/kmsan.git master	73d62e81	51a9082e	.config	log	report	info
ci-upstream-kmsan-gce	2020/12/08 02:37	https://github.com/google/kmsan.git master	73d62e81	51a9082e	.config	log	report	info
ci-upstream-kmsan-gce	2020/12/08 02:23	https://github.com/google/kmsan.git master	73d62e81	51a9082e	.config	log	report	info