Subject: KMSAN: uninit-value in smsc95xx_wait_eeprom (2)

From: syzbot <[email-masked]>
Date: Tue, 08 Dec 2020 04:13:11 -0800

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=178d246b500000
kernel config:  https://syzkaller.appspot.com/x/.config?x=eef728deea880383
dashboard link: https://syzkaller.appspot.com/bug?extid=94b1393490c2c70b781b
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: [email-masked]

=====================================================
BUG: KMSAN: uninit-value in smsc95xx_wait_eeprom+0x223/0x3e0 drivers/net/usb/smsc95xx.c:303
CPU: 1 PID: 28836 Comm: kworker/1:1 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
 smsc95xx_wait_eeprom+0x223/0x3e0 drivers/net/usb/smsc95xx.c:303
 smsc95xx_read_eeprom+0x46d/0xa10 drivers/net/usb/smsc95xx.c:360
 smsc95xx_init_mac_address drivers/net/usb/smsc95xx.c:769 [inline]
 smsc95xx_bind+0x811/0x1d30 drivers/net/usb/smsc95xx.c:1090
 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.i@smsc95xx_wait_eeprom created at:
 __smsc95xx_read_reg drivers/net/usb/smsc95xx.c:77 [inline]
 smsc95xx_read_reg drivers/net/usb/smsc95xx.c:141 [inline]
 smsc95xx_wait_eeprom+0x9d/0x3e0 drivers/net/usb/smsc95xx.c:297
 __smsc95xx_read_reg drivers/net/usb/smsc95xx.c:77 [inline]
 smsc95xx_read_reg drivers/net/usb/smsc95xx.c:141 [inline]
 smsc95xx_wait_eeprom+0x9d/0x3e0 drivers/net/usb/smsc95xx.c:297
=====================================================

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