Subject: [syzbot] KMSAN: uninit-value in asix_mdio_write_nopm

From: syzbot <[email-masked]>
Date: Tue, 15 Mar 2022 08:26:23 -0700

Hello,

syzbot found the following issue on:

HEAD commit:    724946410067 x86: kmsan: enable KMSAN builds for x86
git tree:       https://github.com/google/kmsan.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=151d8ea9700000
kernel config:  https://syzkaller.appspot.com/x/.config?x=28718f555f258365
dashboard link: https://syzkaller.appspot.com/bug?extid=737f7d251877e50f3dce
compiler:       clang version 14.0.0 (/usr/local/google/src/llvm-git-monorepo 2b554920f11c8b763cd9ed9003f4e19b919b8e1f), GNU ld (GNU Binutils for Debian) 2.35.2

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]

usb 6-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
usb 6-1: Product: syz
usb 6-1: Manufacturer: syz
usb 6-1: SerialNumber: syz
usb 6-1: config 0 descriptor??
asix 6-1:0.0 (unnamed net_device) (uninitialized): Failed to read reg index 0x0000: -71
=====================================================
BUG: KMSAN: uninit-value in asix_check_host_enable drivers/net/usb/asix_common.c:84 [inline]
BUG: KMSAN: uninit-value in asix_mdio_write_nopm+0x556/0x9d0 drivers/net/usb/asix_common.c:605
 asix_check_host_enable drivers/net/usb/asix_common.c:84 [inline]
 asix_mdio_write_nopm+0x556/0x9d0 drivers/net/usb/asix_common.c:605
 ax88772a_hw_reset+0xa67/0x12e0 drivers/net/usb/asix_devices.c:524
 ax88772_bind+0x750/0x1770 drivers/net/usb/asix_devices.c:762
 usbnet_probe+0x1251/0x4160 drivers/net/usb/usbnet.c:1747
 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 smsr.i created at:
 asix_mdio_write_nopm+0xe7/0x9d0 drivers/net/usb/asix_common.c:605
 ax88772a_hw_reset+0xa67/0x12e0 drivers/net/usb/asix_devices.c:524

CPU: 1 PID: 3515 Comm: kworker/1:3 Not tainted 5.17.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: usb_hub_wq hub_event
=====================================================

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