KASAN: use-after-free Read in h5_reset_rx

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    7a92eb7cc1dc Add linux-next specific files for 20190215
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=10b2f400c00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=b16fd68f18a50133
dashboard link: https://syzkaller.appspot.com/bug?extid=899a33dc0fa0dbaf06a6
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+899a33dc0fa0dbaf06a6@xxxxxxxxxxxxxxxxxxxxxxxxx

Bluetooth: Invalid header checksum
==================================================================
BUG: KASAN: use-after-free in h5_reset_rx+0xe0/0x100  
drivers/bluetooth/hci_h5.c:544
Read of size 8 at addr ffff88809117be18 by task kworker/u4:4/880

CPU: 1 PID: 880 Comm: kworker/u4:4 Not tainted 5.0.0-rc6-next-20190215 #36
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Workqueue: events_unbound flush_to_ldisc
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x172/0x1f0 lib/dump_stack.c:113
 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:187
 kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:132
 h5_reset_rx+0xe0/0x100 drivers/bluetooth/hci_h5.c:544
 h5_rx_3wire_hdr+0x2f5/0x3c0 drivers/bluetooth/hci_h5.c:455
 h5_recv+0x30a/0x4c0 drivers/bluetooth/hci_h5.c:578
 hci_uart_tty_receive+0x22b/0x530 drivers/bluetooth/hci_ldisc.c:607
 tty_ldisc_receive_buf+0x164/0x1c0 drivers/tty/tty_buffer.c:465
 tty_port_default_receive_buf+0x7d/0xb0 drivers/tty/tty_port.c:38
 receive_buf drivers/tty/tty_buffer.c:481 [inline]
 flush_to_ldisc+0x228/0x390 drivers/tty/tty_buffer.c:533
 process_one_work+0x98e/0x1790 kernel/workqueue.c:2267
 worker_thread+0x98/0xe40 kernel/workqueue.c:2413
 kthread+0x357/0x430 kernel/kthread.c:253
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352

Allocated by task 6242:
 save_stack+0x45/0xd0 mm/kasan/common.c:75
 set_track mm/kasan/common.c:87 [inline]
 __kasan_kmalloc mm/kasan/common.c:497 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:470
 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:511
 kmem_cache_alloc_trace+0x151/0x760 mm/slab.c:3615
 kmalloc include/linux/slab.h:548 [inline]
 kzalloc include/linux/slab.h:743 [inline]
 h5_open+0x4e4/0x5f0 drivers/bluetooth/hci_h5.c:222
 hci_uart_set_proto drivers/bluetooth/hci_ldisc.c:686 [inline]
 hci_uart_tty_ioctl+0x2d4/0xa70 drivers/bluetooth/hci_ldisc.c:748
 tty_ioctl+0xac9/0x14d0 drivers/tty/tty_io.c:2664
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:509 [inline]
 do_vfs_ioctl+0xd6e/0x1390 fs/ioctl.c:696
 ksys_ioctl+0xab/0xd0 fs/ioctl.c:713
 __do_sys_ioctl fs/ioctl.c:720 [inline]
 __se_sys_ioctl fs/ioctl.c:718 [inline]
 __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718
 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 6242:
 save_stack+0x45/0xd0 mm/kasan/common.c:75
 set_track mm/kasan/common.c:87 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:459
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:467
 __cache_free mm/slab.c:3491 [inline]
 kfree+0xcf/0x230 mm/slab.c:3816
 h5_close+0x11a/0x150 drivers/bluetooth/hci_h5.c:266
 hci_uart_set_proto drivers/bluetooth/hci_ldisc.c:696 [inline]
 hci_uart_tty_ioctl+0x839/0xa70 drivers/bluetooth/hci_ldisc.c:748
 tty_ioctl+0xac9/0x14d0 drivers/tty/tty_io.c:2664
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:509 [inline]
 do_vfs_ioctl+0xd6e/0x1390 fs/ioctl.c:696
 ksys_ioctl+0xab/0xd0 fs/ioctl.c:713
 __do_sys_ioctl fs/ioctl.c:720 [inline]
 __se_sys_ioctl fs/ioctl.c:718 [inline]
 __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718
 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff88809117bb40
 which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 728 bytes inside of
 1024-byte region [ffff88809117bb40, ffff88809117bf40)
The buggy address belongs to the page:
page:ffffea0002445e80 count:1 mapcount:0 mapping:ffff88812c3f0ac0 index:0x0  
compound_mapcount: 0
flags: 0x1fffc0000010200(slab|head)
raw: 01fffc0000010200 ffffea000226a888 ffffea000097a788 ffff88812c3f0ac0
raw: 0000000000000000 ffff88809117a040 0000000100000007 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88809117bd00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88809117bd80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ffff88809117be00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff88809117be80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88809117bf00: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
==================================================================


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