KMSAN: uninit-value in read_sensor_register (2)

KMSAN: uninit-value in read_sensor_register (2)

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    c2453450 kmsan: kcov: prettify the code unpoisoning area->..
git tree:       https://github.com/google/kmsan.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=14c95fe7600000
kernel config:  https://syzkaller.appspot.com/x/.config?x=3684f3c73f43899a
dashboard link: https://syzkaller.appspot.com/bug?extid=64437af5c781a7f0e08e
compiler:       clang version 9.0.0 (/home/glider/llvm/clang  
80fee25776c2fb61e74c1ecb1a523375c2500b69)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15e1a3a0e00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=119f406b600000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+64437af5c781a7f0e08e@syzkaller.appspotmail.com

usb 1-1: New USB device found, idVendor=0ac8, idProduct=c301,  
bcdDevice=8b.4c
usb 1-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
usb 1-1: config 0 descriptor??
gspca_main: vc032x-2.14.0 probing 0ac8:c301
gspca_vc032x: reg_w err -71
=====================================================
BUG: KMSAN: uninit-value in read_sensor_register+0x4b7/0xd30  
drivers/media/usb/gspca/vc032x.c:2971
CPU: 1 PID: 3904 Comm: kworker/1:2 Not tainted 5.4.0-rc3+ #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+0x14a/0x2f0 mm/kmsan/kmsan_report.c:109
  __msan_warning+0x73/0xf0 mm/kmsan/kmsan_instr.c:245
  read_sensor_register+0x4b7/0xd30 drivers/media/usb/gspca/vc032x.c:2971
  vc032x_probe_sensor drivers/media/usb/gspca/vc032x.c:3032 [inline]
  sd_init+0x2cf3/0x4530 drivers/media/usb/gspca/vc032x.c:3163
  gspca_dev_probe2+0xe93/0x2230 drivers/media/usb/gspca/gspca.c:1532
  gspca_dev_probe+0x346/0x3b0 drivers/media/usb/gspca/gspca.c:1605
  sd_probe+0x8d/0xa0 drivers/media/usb/gspca/gl860/gl860.c:511
  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

Uninit was created at:
  kmsan_save_stack_with_flags mm/kmsan/kmsan.c:150 [inline]
  kmsan_internal_poison_shadow+0x60/0x110 mm/kmsan/kmsan.c:133
  kmsan_slab_alloc+0xaa/0x130 mm/kmsan/kmsan_hooks.c:101
  slab_alloc_node mm/slub.c:2792 [inline]
  slab_alloc mm/slub.c:2801 [inline]
  kmem_cache_alloc_trace+0x8c5/0xd20 mm/slub.c:2818
  kmalloc include/linux/slab.h:556 [inline]
  gspca_dev_probe2+0x30d/0x2230 drivers/media/usb/gspca/gspca.c:1464
  gspca_dev_probe+0x346/0x3b0 drivers/media/usb/gspca/gspca.c:1605
  sd_probe+0x8d/0xa0 drivers/media/usb/gspca/gl860/gl860.c:511
  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
=====================================================


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