KASAN: invalid-free in disconnect_rio

KASAN: invalid-free in disconnect_rio

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    9a33b369 usb-fuzzer: main usb gadget fuzzer driver
git tree:       https://github.com/google/kasan/tree/usb-fuzzer
console output: https://syzkaller.appspot.com/x/log.txt?x=174ce2e3200000
kernel config:  https://syzkaller.appspot.com/x/.config?x=23e37f59d94ddd15
dashboard link: https://syzkaller.appspot.com/bug?extid=35f04d136fc975a70da4
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=138150f3200000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1290c22d200000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+35f04d136fc975a70da4@syzkaller.appspotmail.com

usb 6-1: USB disconnect, device number 2
rio500 3-1:0.110: USB Rio disconnected.
usb 4-1: USB disconnect, device number 2
==================================================================
usb 1-1: USB disconnect, device number 2
BUG: KASAN: double-free or invalid-free in slab_free mm/slub.c:3003 [inline]
BUG: KASAN: double-free or invalid-free in kfree+0xce/0x290 mm/slub.c:3958
usb 2-1: USB disconnect, device number 2

CPU: 0 PID: 5152 Comm: kworker/0:4 Not tainted 5.1.0-rc4-319354-g9a33b36 #3
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+0xe8/0x16e lib/dump_stack.c:113
  print_address_description+0x6c/0x236 mm/kasan/report.c:187
  kasan_report_invalid_free+0x66/0xa0 mm/kasan/report.c:278
usb 5-1: USB disconnect, device number 2
  __kasan_slab_free+0x162/0x180 mm/kasan/common.c:438
  slab_free_hook mm/slub.c:1429 [inline]
  slab_free_freelist_hook+0x5e/0x140 mm/slub.c:1456
  slab_free mm/slub.c:3003 [inline]
  kfree+0xce/0x290 mm/slub.c:3958
  disconnect_rio+0x13b/0x200 drivers/usb/misc/rio500.c:506
  usb_unbind_interface+0x1c9/0x980 drivers/usb/core/driver.c:423
  __device_release_driver drivers/base/dd.c:1082 [inline]
  device_release_driver_internal+0x436/0x4f0 drivers/base/dd.c:1113
  bus_remove_device+0x302/0x5c0 drivers/base/bus.c:556
  device_del+0x467/0xb90 drivers/base/core.c:2269
  usb_disable_device+0x242/0x790 drivers/usb/core/message.c:1235
  usb_disconnect+0x298/0x870 drivers/usb/core/hub.c:2197
  hub_port_connect drivers/usb/core/hub.c:4940 [inline]
  hub_port_connect_change drivers/usb/core/hub.c:5204 [inline]
  port_event drivers/usb/core/hub.c:5350 [inline]
  hub_event+0xcd2/0x3b00 drivers/usb/core/hub.c:5432
  process_one_work+0x90f/0x1580 kernel/workqueue.c:2269
  worker_thread+0x9b/0xe20 kernel/workqueue.c:2415
  kthread+0x313/0x420 kernel/kthread.c:253
  ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352

Allocated by task 5152:
  set_track mm/kasan/common.c:87 [inline]
  __kasan_kmalloc mm/kasan/common.c:497 [inline]
  __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:470
  kmalloc include/linux/slab.h:547 [inline]
  probe_rio+0x188/0x268 drivers/usb/misc/rio500.c:471
  usb_probe_interface+0x31d/0x820 drivers/usb/core/driver.c:361
  really_probe+0x2da/0xb10 drivers/base/dd.c:509
  driver_probe_device+0x21d/0x350 drivers/base/dd.c:671
  __device_attach_driver+0x1d8/0x290 drivers/base/dd.c:778
  bus_for_each_drv+0x163/0x1e0 drivers/base/bus.c:454
  __device_attach+0x223/0x3a0 drivers/base/dd.c:844
  bus_probe_device+0x1f1/0x2a0 drivers/base/bus.c:514
  device_add+0xad2/0x16e0 drivers/base/core.c:2106
  usb_set_configuration+0xdf7/0x1740 drivers/usb/core/message.c:2021
  generic_probe+0xa2/0xda drivers/usb/core/generic.c:210
  usb_probe_device+0xc0/0x150 drivers/usb/core/driver.c:266
  really_probe+0x2da/0xb10 drivers/base/dd.c:509
  driver_probe_device+0x21d/0x350 drivers/base/dd.c:671
  __device_attach_driver+0x1d8/0x290 drivers/base/dd.c:778
  bus_for_each_drv+0x163/0x1e0 drivers/base/bus.c:454
  __device_attach+0x223/0x3a0 drivers/base/dd.c:844
  bus_probe_device+0x1f1/0x2a0 drivers/base/bus.c:514
  device_add+0xad2/0x16e0 drivers/base/core.c:2106
  usb_new_device.cold+0x537/0xccf 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+0x138e/0x3b00 drivers/usb/core/hub.c:5432
  process_one_work+0x90f/0x1580 kernel/workqueue.c:2269
  worker_thread+0x9b/0xe20 kernel/workqueue.c:2415
  kthread+0x313/0x420 kernel/kthread.c:253
  ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352

Freed by task 585:
  set_track mm/kasan/common.c:87 [inline]
  __kasan_slab_free+0x130/0x180 mm/kasan/common.c:459
  slab_free_hook mm/slub.c:1429 [inline]
  slab_free_freelist_hook+0x5e/0x140 mm/slub.c:1456
  slab_free mm/slub.c:3003 [inline]
  kfree+0xce/0x290 mm/slub.c:3958
  disconnect_rio+0x13b/0x200 drivers/usb/misc/rio500.c:506
  usb_unbind_interface+0x1c9/0x980 drivers/usb/core/driver.c:423
  __device_release_driver drivers/base/dd.c:1082 [inline]
  device_release_driver_internal+0x436/0x4f0 drivers/base/dd.c:1113
  bus_remove_device+0x302/0x5c0 drivers/base/bus.c:556
  device_del+0x467/0xb90 drivers/base/core.c:2269
  usb_disable_device+0x242/0x790 drivers/usb/core/message.c:1235
  usb_disconnect+0x298/0x870 drivers/usb/core/hub.c:2197
  hub_port_connect drivers/usb/core/hub.c:4940 [inline]
  hub_port_connect_change drivers/usb/core/hub.c:5204 [inline]
  port_event drivers/usb/core/hub.c:5350 [inline]
  hub_event+0xcd2/0x3b00 drivers/usb/core/hub.c:5432
  process_one_work+0x90f/0x1580 kernel/workqueue.c:2269
  worker_thread+0x9b/0xe20 kernel/workqueue.c:2415
  kthread+0x313/0x420 kernel/kthread.c:253
  ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352

The buggy address belongs to the object at ffff88808863a200
  which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 0 bytes inside of
  4096-byte region [ffff88808863a200, ffff88808863b200)
usb 3-1: new high-speed USB device number 3 using dummy_hcd
The buggy address belongs to the page:
page:ffffea0002218e00 count:1 mapcount:0 mapping:ffff88812c3f4600 index:0x0  
compound_mapcount: 0
flags: 0xfff00000010200(slab|head)
raw: 00fff00000010200 0000000000000000 0000000600000001 ffff88812c3f4600
raw: 0000000000000000 0000000000070007 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
  ffff88808863a100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
  ffff88808863a180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> ffff88808863a200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                    ^
  ffff88808863a280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
  ffff88808863a300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


---
This bug is generated by a bot. It may contain errors.
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Re: KASAN: invalid-free in disconnect_rio

[Oliver Neukum]

On Fr, 2019-04-12 at 04:36 -0700, syzbot wrote:
> Hello,
> 
> syzbot found the following crash on:
> 
> HEAD commit:    9a33b369 usb-fuzzer: main usb gadget fuzzer driver
> git tree:       https://github.com/google/kasan/tree/usb-fuzzer
> console output: https://syzkaller.appspot.com/x/log.txt?x=174ce2e3200000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=23e37f59d94ddd15
> dashboard link: https://syzkaller.appspot.com/bug?extid=35f04d136fc975a70da4
> compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=138150f3200000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1290c22d200000
> 
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+35f04d136fc975a70da4@syzkaller.appspotmail.com
> 
> usb 6-1: USB disconnect, device number 2
> rio500 3-1:0.110: USB Rio disconnected.
> usb 4-1: USB disconnect, device number 2
> ==================================================================
> usb 1-1: USB disconnect, device number 2
> BUG: KASAN: double-free or invalid-free in slab_free mm/slub.c:3003 [inline]
> BUG: KASAN: double-free or invalid-free in kfree+0xce/0x290 mm/slub.c:3958
> usb 2-1: USB disconnect, device number 2
> 

Try as I might, I don't understand this. I can see a memory leak,
but not a double free.

	Regards
		Oliver

Re: KASAN: invalid-free in disconnect_rio

[Andrey Konovalov]

On Tue, Apr 30, 2019 at 2:58 PM Oliver Neukum <oneukum@suse.com> wrote:
>
> On Fr, 2019-04-12 at 04:36 -0700, syzbot wrote:
> > Hello,
> >
> > syzbot found the following crash on:
> >
> > HEAD commit:    9a33b369 usb-fuzzer: main usb gadget fuzzer driver
> > git tree:       https://github.com/google/kasan/tree/usb-fuzzer
> > console output: https://syzkaller.appspot.com/x/log.txt?x=174ce2e3200000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=23e37f59d94ddd15
> > dashboard link: https://syzkaller.appspot.com/bug?extid=35f04d136fc975a70da4
> > compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
> > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=138150f3200000
> > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1290c22d200000
> >
> > IMPORTANT: if you fix the bug, please add the following tag to the commit:
> > Reported-by: syzbot+35f04d136fc975a70da4@syzkaller.appspotmail.com
> >
> > usb 6-1: USB disconnect, device number 2
> > rio500 3-1:0.110: USB Rio disconnected.
> > usb 4-1: USB disconnect, device number 2
> > ==================================================================
> > usb 1-1: USB disconnect, device number 2
> > BUG: KASAN: double-free or invalid-free in slab_free mm/slub.c:3003 [inline]
> > BUG: KASAN: double-free or invalid-free in kfree+0xce/0x290 mm/slub.c:3958
> > usb 2-1: USB disconnect, device number 2
> >
>
> Try as I might, I don't understand this. I can see a memory leak,
> but not a double free.

I took a look at this some time ago, and I was under the impression
that this driver doesn't handle multiple devices being connected at
the same time well.

>
>         Regards
>                 Oliver
>

Re: KASAN: invalid-free in disconnect_rio

[Oliver Neukum]

On Di, 2019-04-30 at 15:02 +0200, Andrey Konovalov wrote:
> On Tue, Apr 30, 2019 at 2:58 PM Oliver Neukum <oneukum@suse.com> wrote:
> > 
> > On Fr, 2019-04-12 at 04:36 -0700, syzbot wrote:
> > > Hello,
> > > 
> > > syzbot found the following crash on:
> > > 
> > > HEAD commit:    9a33b369 usb-fuzzer: main usb gadget fuzzer driver
> > > git tree:       https://github.com/google/kasan/tree/usb-fuzzer
> > > console output: https://syzkaller.appspot.com/x/log.txt?x=174ce2e3200000
> > > kernel config:  https://syzkaller.appspot.com/x/.config?x=23e37f59d94ddd15
> > > dashboard link: https://syzkaller.appspot.com/bug?extid=35f04d136fc975a70da4
> > > compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
> > > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=138150f3200000
> > > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1290c22d200000
> > > 
> > > IMPORTANT: if you fix the bug, please add the following tag to the commit:
> > > Reported-by: syzbot+35f04d136fc975a70da4@syzkaller.appspotmail.com
> > > 
> > > usb 6-1: USB disconnect, device number 2
> > > rio500 3-1:0.110: USB Rio disconnected.
> > > usb 4-1: USB disconnect, device number 2
> > > ==================================================================
> > > usb 1-1: USB disconnect, device number 2
> > > BUG: KASAN: double-free or invalid-free in slab_free mm/slub.c:3003 [inline]
> > > BUG: KASAN: double-free or invalid-free in kfree+0xce/0x290 mm/slub.c:3958
> > > usb 2-1: USB disconnect, device number 2
> > > 
> > 
> > Try as I might, I don't understand this. I can see a memory leak,
> > but not a double free.
> 
> I took a look at this some time ago, and I was under the impression
> that this driver doesn't handle multiple devices being connected at
> the same time well.


You are right. A global variable is used. A fix is being worked on.

	Regards
		Oliver