Subject: KMSAN: uninit-value in ax88172a_bind

From: syzbot <[email-masked]>
Date: Mon, 14 Oct 2019 22:10:06 -0700

Hello,

syzbot found the following crash on:

HEAD commit:    fa169025 kmsan: get rid of unused static functions in kmsa..
git tree:       https://github.com/google/kmsan.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=1432a653600000
kernel config:  https://syzkaller.appspot.com/x/.config?x=49548798e87d32d7
dashboard link: https://syzkaller.appspot.com/bug?extid=a8d4acdad35e6bbca308
compiler:       clang version 9.0.0 (/home/glider/llvm/clang  
80fee25776c2fb61e74c1ecb1a523375c2500b69)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14743a6f600000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=125bdbc7600000

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=0b95, idProduct=172a,  
bcdDevice=9b.e9
usb 1-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
usb 1-1: config 0 descriptor??
=====================================================
BUG: KMSAN: uninit-value in ax88172a_bind+0x76d/0xf80  
drivers/net/usb/ax88172a.c:217
CPU: 1 PID: 3632 Comm: kworker/1:2 Not tainted 5.4.0-rc2+ #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+0x191/0x1f0 lib/dump_stack.c:113
  kmsan_report+0x14e/0x2c0 mm/kmsan/kmsan_report.c:110
  __msan_warning+0x73/0xe0 mm/kmsan/kmsan_instr.c:245
  ax88172a_bind+0x76d/0xf80 drivers/net/usb/ax88172a.c:217
  usbnet_probe+0x10d3/0x39d0 drivers/net/usb/usbnet.c:1730
  usb_probe_interface+0xd19/0x1310 drivers/usb/core/driver.c:361
  really_probe+0xd91/0x1f90 drivers/base/dd.c:552
  driver_probe_device+0x1ba/0x510 drivers/base/dd.c:721
  __device_attach_driver+0x5b8/0x790 drivers/base/dd.c:828
  bus_for_each_drv+0x28e/0x3b0 drivers/base/bus.c:430
  __device_attach+0x489/0x750 drivers/base/dd.c:894
  device_initial_probe+0x4a/0x60 drivers/base/dd.c:941
  bus_probe_device+0x131/0x390 drivers/base/bus.c:490
  device_add+0x25b5/0x2df0 drivers/base/core.c:2201
  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+0xd91/0x1f90 drivers/base/dd.c:552
  driver_probe_device+0x1ba/0x510 drivers/base/dd.c:721
  __device_attach_driver+0x5b8/0x790 drivers/base/dd.c:828
  bus_for_each_drv+0x28e/0x3b0 drivers/base/bus.c:430
  __device_attach+0x489/0x750 drivers/base/dd.c:894
  device_initial_probe+0x4a/0x60 drivers/base/dd.c:941
  bus_probe_device+0x131/0x390 drivers/base/bus.c:490
  device_add+0x25b5/0x2df0 drivers/base/core.c:2201
  usb_new_device+0x23e5/0x2fb0 drivers/usb/core/hub.c:2536
  hub_port_connect drivers/usb/core/hub.c:5098 [inline]
  hub_port_connect_change drivers/usb/core/hub.c:5213 [inline]
  port_event drivers/usb/core/hub.c:5359 [inline]
  hub_event+0x581d/0x72f0 drivers/usb/core/hub.c:5441
  process_one_work+0x1572/0x1ef0 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@ax88172a_bind
Variable was created at:
  ax88172a_bind+0x66/0xf80 drivers/net/usb/ax88172a.c:186
  ax88172a_bind+0x66/0xf80 drivers/net/usb/ax88172a.c:186
=====================================================

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