Message-ID: <000000000000de50d7059ba6acd5@google.com>
Date:   Wed, 08 Jan 2020 12:24:10 -0800
From:   syzbot <syzbot+75287f75e2fedd69d680@...kaller.appspotmail.com>
To:     andreyknvl@...gle.com, bnvandana@...il.com,
        hverkuil-cisco@...all.nl, laurent.pinchart@...asonboard.com,
        linux-kernel@...r.kernel.org, linux-media@...r.kernel.org,
        linux-usb@...r.kernel.org, mchehab@...nel.org,
        syzkaller-bugs@...glegroups.com
Subject: KASAN: use-after-free Read in v4l2_release (3)

Hello,

syzbot found the following crash on:

HEAD commit:    ae179410 usb: gadget: add raw-gadget interface
git tree:       https://github.com/google/kasan.git usb-fuzzer
console output: https://syzkaller.appspot.com/x/log.txt?x=132aa915e00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=57adcee0a60380e2
dashboard link: https://syzkaller.appspot.com/bug?extid=75287f75e2fedd69d680
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)

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+75287f75e2fedd69d680@...kaller.appspotmail.com

usbvision_radio_close: Final disconnect
==================================================================
BUG: KASAN: use-after-free in v4l2_release+0x2f1/0x390  
drivers/media/v4l2-core/v4l2-dev.c:459
Read of size 4 at addr ffff8881d13b5068 by task v4l_id/20136

CPU: 1 PID: 20136 Comm: v4l_id Not tainted 5.5.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Call Trace:
  __dump_stack lib/dump_stack.c:77 [inline]
  dump_stack+0xef/0x16e lib/dump_stack.c:118
  print_address_description.constprop.0+0x16/0x200 mm/kasan/report.c:374
  __kasan_report.cold+0x37/0x7f mm/kasan/report.c:506
  kasan_report+0xe/0x20 mm/kasan/common.c:639
  v4l2_release+0x2f1/0x390 drivers/media/v4l2-core/v4l2-dev.c:459
  __fput+0x2d7/0x840 fs/file_table.c:280
  task_work_run+0x13f/0x1c0 kernel/task_work.c:113
  tracehook_notify_resume include/linux/tracehook.h:188 [inline]
  exit_to_usermode_loop+0x1d2/0x200 arch/x86/entry/common.c:164
  prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline]
  syscall_return_slowpath arch/x86/entry/common.c:278 [inline]
  do_syscall_64+0x4e0/0x5c0 arch/x86/entry/common.c:304
  entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f70446a32b0
Code: 40 75 0b 31 c0 48 83 c4 08 e9 0c ff ff ff 48 8d 3d c5 32 08 00 e8 c0  
07 02 00 83 3d 45 a3 2b 00 00 75 10 b8 03 00 00 00 0f 05 <48> 3d 01 f0 ff  
ff 73 31 c3 48 83 ec 08 e8 ce 8a 01 00 48 89 04 24
RSP: 002b:00007ffee1722fd8 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000003 RCX: 00007f70446a32b0
RDX: 0000000000000013 RSI: 0000000080685600 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000400884
R13: 00007ffee1723130 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 14633:
  save_stack+0x1b/0x80 mm/kasan/common.c:72
  set_track mm/kasan/common.c:80 [inline]
  __kasan_kmalloc mm/kasan/common.c:513 [inline]
  __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:486
  kmalloc include/linux/slab.h:556 [inline]
  kzalloc include/linux/slab.h:670 [inline]
  usbvision_alloc drivers/media/usb/usbvision/usbvision-video.c:1315 [inline]
  usbvision_probe.cold+0x5c5/0x1f21  
drivers/media/usb/usbvision/usbvision-video.c:1469
  usb_probe_interface+0x305/0x7a0 drivers/usb/core/driver.c:361
  really_probe+0x281/0x6d0 drivers/base/dd.c:548
  driver_probe_device+0x104/0x210 drivers/base/dd.c:721
  __device_attach_driver+0x1c2/0x220 drivers/base/dd.c:828
  bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:430
  __device_attach+0x217/0x360 drivers/base/dd.c:894
  bus_probe_device+0x1e4/0x290 drivers/base/bus.c:490
  device_add+0x141f/0x1bc0 drivers/base/core.c:2487
  usb_set_configuration+0xe38/0x16c0 drivers/usb/core/message.c:2023
  generic_probe+0x9d/0xd5 drivers/usb/core/generic.c:210
  usb_probe_device+0x99/0x100 drivers/usb/core/driver.c:266
  really_probe+0x281/0x6d0 drivers/base/dd.c:548
  driver_probe_device+0x104/0x210 drivers/base/dd.c:721
  __device_attach_driver+0x1c2/0x220 drivers/base/dd.c:828
  bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:430
  __device_attach+0x217/0x360 drivers/base/dd.c:894
  bus_probe_device+0x1e4/0x290 drivers/base/bus.c:490
  device_add+0x141f/0x1bc0 drivers/base/core.c:2487
  usb_new_device.cold+0x6a4/0xe79 drivers/usb/core/hub.c:2537
  hub_port_connect drivers/usb/core/hub.c:5184 [inline]
  hub_port_connect_change drivers/usb/core/hub.c:5324 [inline]
  port_event drivers/usb/core/hub.c:5470 [inline]
  hub_event+0x1e59/0x3860 drivers/usb/core/hub.c:5552
  process_one_work+0x92b/0x1530 kernel/workqueue.c:2264
  process_scheduled_works kernel/workqueue.c:2326 [inline]
  worker_thread+0x7ab/0xe20 kernel/workqueue.c:2412
  kthread+0x318/0x420 kernel/kthread.c:255
  ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Freed by task 20136:
  save_stack+0x1b/0x80 mm/kasan/common.c:72
  set_track mm/kasan/common.c:80 [inline]
  kasan_set_free_info mm/kasan/common.c:335 [inline]
  __kasan_slab_free+0x129/0x170 mm/kasan/common.c:474
  slab_free_hook mm/slub.c:1425 [inline]
  slab_free_freelist_hook mm/slub.c:1458 [inline]
  slab_free mm/slub.c:3005 [inline]
  kfree+0xda/0x310 mm/slub.c:3957
  usbvision_release+0x181/0x1c0  
drivers/media/usb/usbvision/usbvision-video.c:1364
  usbvision_radio_close.cold+0x2b/0x74  
drivers/media/usb/usbvision/usbvision-video.c:1130
  v4l2_release+0x2e7/0x390 drivers/media/v4l2-core/v4l2-dev.c:455
  __fput+0x2d7/0x840 fs/file_table.c:280
  task_work_run+0x13f/0x1c0 kernel/task_work.c:113
  tracehook_notify_resume include/linux/tracehook.h:188 [inline]
  exit_to_usermode_loop+0x1d2/0x200 arch/x86/entry/common.c:164
  prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline]
  syscall_return_slowpath arch/x86/entry/common.c:278 [inline]
  do_syscall_64+0x4e0/0x5c0 arch/x86/entry/common.c:304
  entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8881d13b4000
  which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 4200 bytes inside of
  8192-byte region [ffff8881d13b4000, ffff8881d13b6000)
The buggy address belongs to the page:
page:ffffea000744ec00 refcount:1 mapcount:0 mapping:ffff8881da40c500  
index:0x0 compound_mapcount: 0
raw: 0200000000010200 ffffea0007392a00 0000000300000003 ffff8881da40c500
raw: 0000000000000000 0000000000020002 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
  ffff8881d13b4f00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
  ffff8881d13b4f80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ffff8881d13b5000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                           ^
  ffff8881d13b5080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
  ffff8881d13b5100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


---
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