Subject: Re: KMSAN: uninit-value in ax88178_bind

From: syzbot <[email-masked]>
Date: Mon, 01 Jul 2019 04:38:05 -0700

syzbot has found a reproducer for the following crash on:

HEAD commit:    41550654 [UPSTREAM] KVM: x86: degrade WARN to pr_warn_rate..
git tree:       kmsan
console output: https://syzkaller.appspot.com/x/log.txt?x=1577f4d5a00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=40511ad0c5945201
dashboard link: https://syzkaller.appspot.com/bug?extid=abd25d675d47f23f188c
compiler:       clang version 9.0.0 (/home/glider/llvm/clang  
80fee25776c2fb61e74c1ecb1a523375c2500b69)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=17ea8283a00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=11a1f57ba00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: [email-masked]

usb 1-1: config 0 has no interface number 0
usb 1-1: New USB device found, idVendor=04bb, idProduct=0930,  
bcdDevice=d2.4a
usb 1-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
usb 1-1: config 0 descriptor??
==================================================================
BUG: KMSAN: uninit-value in is_valid_ether_addr  
include/linux/etherdevice.h:195 [inline]
BUG: KMSAN: uninit-value in asix_set_netdev_dev_addr  
drivers/net/usb/asix_devices.c:61 [inline]
BUG: KMSAN: uninit-value in ax88178_bind+0x635/0xad0  
drivers/net/usb/asix_devices.c:1075
CPU: 1 PID: 30 Comm: kworker/1:1 Not tainted 5.2.0-rc4+ #7
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+0x191/0x1f0 lib/dump_stack.c:113
  kmsan_report+0x162/0x2d0 mm/kmsan/kmsan.c:611
  __msan_warning+0x75/0xe0 mm/kmsan/kmsan_instr.c:304
  is_valid_ether_addr include/linux/etherdevice.h:195 [inline]
  asix_set_netdev_dev_addr drivers/net/usb/asix_devices.c:61 [inline]
  ax88178_bind+0x635/0xad0 drivers/net/usb/asix_devices.c:1075
  usbnet_probe+0x10d3/0x3950 drivers/net/usb/usbnet.c:1722
  usb_probe_interface+0xd19/0x1310 drivers/usb/core/driver.c:361
  really_probe+0x1344/0x1d90 drivers/base/dd.c:513
  driver_probe_device+0x1ba/0x510 drivers/base/dd.c:670
  __device_attach_driver+0x5b8/0x790 drivers/base/dd.c:777
  bus_for_each_drv+0x28e/0x3b0 drivers/base/bus.c:454
  __device_attach+0x489/0x750 drivers/base/dd.c:843
  device_initial_probe+0x4a/0x60 drivers/base/dd.c:890
  bus_probe_device+0x131/0x390 drivers/base/bus.c:514
  device_add+0x25b5/0x2df0 drivers/base/core.c:2111
  usb_set_configuration+0x309f/0x3710 drivers/usb/core/message.c:2027
  generic_probe+0xe7/0x280 drivers/usb/core/generic.c:210
  usb_probe_device+0x146/0x200 drivers/usb/core/driver.c:266
  really_probe+0x1344/0x1d90 drivers/base/dd.c:513
  driver_probe_device+0x1ba/0x510 drivers/base/dd.c:670
  __device_attach_driver+0x5b8/0x790 drivers/base/dd.c:777
  bus_for_each_drv+0x28e/0x3b0 drivers/base/bus.c:454
  __device_attach+0x489/0x750 drivers/base/dd.c:843
  device_initial_probe+0x4a/0x60 drivers/base/dd.c:890
  bus_probe_device+0x131/0x390 drivers/base/bus.c:514
  device_add+0x25b5/0x2df0 drivers/base/core.c:2111
  usb_new_device+0x23e5/0x2fb0 drivers/usb/core/hub.c:2534
  hub_port_connect drivers/usb/core/hub.c:5089 [inline]
  hub_port_connect_change drivers/usb/core/hub.c:5204 [inline]
  port_event drivers/usb/core/hub.c:5350 [inline]
  hub_event+0x5853/0x7320 drivers/usb/core/hub.c:5432
  process_one_work+0x1572/0x1f00 kernel/workqueue.c:2269
  worker_thread+0x111b/0x2460 kernel/workqueue.c:2415
  kthread+0x4b5/0x4f0 kernel/kthread.c:256
  ret_from_fork+0x35/0x40 arch/x86/entry/entry_64.S:355

Local variable description: ----buf@ax88178_bind
Variable was created at:
  ax88178_bind+0x60/0xad0 drivers/net/usb/asix_devices.c:1064
  usbnet_probe+0x10d3/0x3950 drivers/net/usb/usbnet.c:1722
==================================================================