[syzbot] [usb?] KMSAN: uninit-value in smsc95xx_eeprom_confirm_not_busy

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 257152fe29be string: use __builtin_memcpy() in strlcpy/str..
git tree: https://github.com/google/kmsan.git master
console+strace: https://syzkaller.appspot.com/x/log.txt?x=156aa484a80000
kernel config: https://syzkaller.appspot.com/x/.config?x=d16a560a6e6eb097
dashboard link: https://syzkaller.appspot.com/bug?extid=2c97a98a5ba9ea9c23bd
compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15433d14a80000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12528ac8a80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/8e2711366405/disk-257152fe.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/cec15df7e485/vmlinux-257152fe.xz
kernel image: https://storage.googleapis.com/syzbot-assets/f212903d5649/bzImage-257152fe.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+2c97a9...@syzkaller.appspotmail.com

=====================================================
BUG: KMSAN: uninit-value in smsc95xx_eeprom_confirm_not_busy+0x1eb/0x360 drivers/net/usb/smsc95xx.c:348
smsc95xx_eeprom_confirm_not_busy+0x1eb/0x360 drivers/net/usb/smsc95xx.c:348
smsc95xx_read_eeprom+0x59/0x670 drivers/net/usb/smsc95xx.c:367
smsc95xx_init_mac_address drivers/net/usb/smsc95xx.c:816 [inline]
smsc95xx_bind+0x6d8/0x22e0 drivers/net/usb/smsc95xx.c:1128
usbnet_probe+0x1011/0x3f20 drivers/net/usb/usbnet.c:1750
usb_probe_interface+0xc75/0x1210 drivers/usb/core/driver.c:396
really_probe+0x506/0xf40 drivers/base/dd.c:658
__driver_probe_device+0x2a7/0x5d0 drivers/base/dd.c:800
driver_probe_device+0x72/0x7b0 drivers/base/dd.c:830
__device_attach_driver+0x55a/0x8f0 drivers/base/dd.c:958
bus_for_each_drv+0x3ff/0x620 drivers/base/bus.c:457
__device_attach+0x3bd/0x640 drivers/base/dd.c:1030
device_initial_probe+0x32/0x40 drivers/base/dd.c:1079
bus_probe_device+0x3d8/0x5a0 drivers/base/bus.c:532
device_add+0x1b6a/0x24b0 drivers/base/core.c:3625
usb_set_configuration+0x31c9/0x38c0 drivers/usb/core/message.c:2211
usb_generic_driver_probe+0x109/0x2a0 drivers/usb/core/generic.c:238
usb_probe_device+0x290/0x4a0 drivers/usb/core/driver.c:293
really_probe+0x506/0xf40 drivers/base/dd.c:658
__driver_probe_device+0x2a7/0x5d0 drivers/base/dd.c:800
driver_probe_device+0x72/0x7b0 drivers/base/dd.c:830
__device_attach_driver+0x55a/0x8f0 drivers/base/dd.c:958
bus_for_each_drv+0x3ff/0x620 drivers/base/bus.c:457
__device_attach+0x3bd/0x640 drivers/base/dd.c:1030
device_initial_probe+0x32/0x40 drivers/base/dd.c:1079
bus_probe_device+0x3d8/0x5a0 drivers/base/bus.c:532
device_add+0x1b6a/0x24b0 drivers/base/core.c:3625
usb_new_device+0x15f6/0x22f0 drivers/usb/core/hub.c:2575
hub_port_connect drivers/usb/core/hub.c:5407 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5551 [inline]
port_event drivers/usb/core/hub.c:5711 [inline]
hub_event+0x577b/0x78a0 drivers/usb/core/hub.c:5793
process_one_work+0xb0d/0x1410 kernel/workqueue.c:2408
worker_thread+0x107e/0x1d60 kernel/workqueue.c:2555
kthread+0x3e8/0x540 kernel/kthread.c:379
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308

Local variable buf.i created at:
smsc95xx_read_reg drivers/net/usb/smsc95xx.c:90 [inline]
smsc95xx_eeprom_confirm_not_busy+0x92/0x360 drivers/net/usb/smsc95xx.c:342
smsc95xx_read_eeprom+0x59/0x670 drivers/net/usb/smsc95xx.c:367

CPU: 0 PID: 9 Comm: kworker/0:1 Not tainted 6.4.0-syzkaller-g257152fe29be #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
Workqueue: usb_hub_wq hub_event
=====================================================


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