KMSAN: uninit-value in smsc75xx_read_eeprom (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 73d62e81 kmsan: random: prevent boot-time reports in _mix_..
git tree: https://github.com/google/kmsan.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=1256cc13500000
kernel config: https://syzkaller.appspot.com/x/.config?x=eef728deea880383
dashboard link: https://syzkaller.appspot.com/bug?extid=341170ccba949fac01a2
compiler: clang version 11.0.0 (https://github.com/llvm/llvm-project.git ca2dcbd030eadbf0aa9b660efe864ff08af6e18b)

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+341170...@syzkaller.appspotmail.com

cdc_ether: probe of 5-1:1.0 failed with error -22
smsc75xx v1.0.0
=====================================================
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: 1 PID: 8502 Comm: kworker/1:0 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
=====================================================


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.