KMSAN: uninit-value in friio_power_ctrl

From: syzbot <syzbot+9e6bf7282557bd1fc80d@syzkaller.appspotmail.com>
To: crope@iki.fi, glider@google.com, linux-kernel@vger.kernel.org,
	linux-media@vger.kernel.org, mchehab@kernel.org,
	syzkaller-bugs@googlegroups.com
Subject: KMSAN: uninit-value in friio_power_ctrl
Date: Wed, 10 Jul 2019 06:48:05 -0700	[thread overview]
Message-ID: <00000000000041eeb7058d53ed4c@google.com> (raw)

Hello,

syzbot found the following crash on:

HEAD commit:    4009f3cf kmsan: slub: fix a compilation warning by moving ..
git tree:       kmsan
console output: https://syzkaller.appspot.com/x/log.txt?x=10b58730600000
kernel config:  https://syzkaller.appspot.com/x/.config?x=40511ad0c5945201
dashboard link: https://syzkaller.appspot.com/bug?extid=9e6bf7282557bd1fc80d
compiler:       clang version 9.0.0 (/home/glider/llvm/clang  
80fee25776c2fb61e74c1ecb1a523375c2500b69)

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+9e6bf7282557bd1fc80d@syzkaller.appspotmail.com

usb 6-1: New USB device found, idVendor=7a69, idProduct=0001,  
bcdDevice=19.36
usb 6-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
usb 6-1: config 0 descriptor??
usb 6-1: dvb_usb_v2: found a '774 Friio White ISDB-T USB2.0' in warm state
==================================================================
BUG: KMSAN: uninit-value in friio_reset  
drivers/media/usb/dvb-usb-v2/gl861.c:433 [inline]
BUG: KMSAN: uninit-value in friio_power_ctrl+0xb3e/0x1a70  
drivers/media/usb/dvb-usb-v2/gl861.c:482
CPU: 1 PID: 17 Comm: kworker/1:0 Not tainted 5.2.0-rc4+ #12
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_report.c:109
  __msan_warning+0x75/0xe0 mm/kmsan/kmsan_instr.c:294
  friio_reset drivers/media/usb/dvb-usb-v2/gl861.c:433 [inline]
  friio_power_ctrl+0xb3e/0x1a70 drivers/media/usb/dvb-usb-v2/gl861.c:482
  dvb_usbv2_device_power_ctrl  
drivers/media/usb/dvb-usb-v2/dvb_usb_core.c:540 [inline]
  dvb_usbv2_init drivers/media/usb/dvb-usb-v2/dvb_usb_core.c:853 [inline]
  dvb_usbv2_probe+0xd3d/0x5dd0  
drivers/media/usb/dvb-usb-v2/dvb_usb_core.c:980
  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: ----rbuf.i@friio_power_ctrl
Variable was created at:
  friio_reset drivers/media/usb/dvb-usb-v2/gl861.c:400 [inline]
  friio_power_ctrl+0x92/0x1a70 drivers/media/usb/dvb-usb-v2/gl861.c:482
  dvb_usbv2_device_power_ctrl  
drivers/media/usb/dvb-usb-v2/dvb_usb_core.c:540 [inline]
  dvb_usbv2_init drivers/media/usb/dvb-usb-v2/dvb_usb_core.c:853 [inline]
  dvb_usbv2_probe+0xd3d/0x5dd0  
drivers/media/usb/dvb-usb-v2/dvb_usb_core.c:980
==================================================================

---
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