KASAN: use-after-free Write in hci_sock_bind

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: cb1f9a16 Linux 4.19.94
git tree: linux-4.19.y
console output: https://syzkaller.appspot.com/x/log.txt?x=14134d15e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=9d03b07719ed036e
dashboard link: https://syzkaller.appspot.com/bug?extid=bdbdd849903b8659f6ea
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12e42515e00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16739d49e00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+bdbdd8...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: use-after-free in atomic_inc
include/asm-generic/atomic-instrumented.h:109 [inline]
BUG: KASAN: use-after-free in hci_sock_bind+0x5b4/0x1120
net/bluetooth/hci_sock.c:1223
Write of size 4 at addr ffff888080ac2e60 by task syz-executor107/9041

CPU: 1 PID: 9041 Comm: syz-executor107 Not tainted 4.19.94-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+0x197/0x210 lib/dump_stack.c:118
print_address_description.cold+0x7c/0x20d mm/kasan/report.c:256
kasan_report_error mm/kasan/report.c:354 [inline]
kasan_report mm/kasan/report.c:412 [inline]
kasan_report.cold+0x8c/0x2ba mm/kasan/report.c:396
check_memory_region_inline mm/kasan/kasan.c:260 [inline]
check_memory_region+0x123/0x190 mm/kasan/kasan.c:267
kasan_check_write+0x14/0x20 mm/kasan/kasan.c:278
atomic_inc include/asm-generic/atomic-instrumented.h:109 [inline]
hci_sock_bind+0x5b4/0x1120 net/bluetooth/hci_sock.c:1223
__sys_bind+0x239/0x290 net/socket.c:1482
__do_sys_bind net/socket.c:1493 [inline]
__se_sys_bind net/socket.c:1491 [inline]
__x64_sys_bind+0x73/0xb0 net/socket.c:1491
do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x449299
Code: e8 ac e7 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7
48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff
ff 0f 83 4b 06 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f4a80986d88 EFLAGS: 00000246 ORIG_RAX: 0000000000000031
RAX: ffffffffffffffda RBX: 00000000006e4a08 RCX: 0000000000449299
RDX: 0000000000000006 RSI: 00000000200007c0 RDI: 0000000000000004
RBP: 00000000006e4a00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006e4a0c
R13: 0000000000000005 R14: 0000000000000004 R15: 00007f4a809876d0

Allocated by task 9039:
save_stack+0x45/0xd0 mm/kasan/kasan.c:448
set_track mm/kasan/kasan.c:460 [inline]
kasan_kmalloc mm/kasan/kasan.c:553 [inline]
kasan_kmalloc+0xce/0xf0 mm/kasan/kasan.c:531
kmem_cache_alloc_trace+0x152/0x760 mm/slab.c:3625
kmalloc include/linux/slab.h:515 [inline]
kzalloc include/linux/slab.h:709 [inline]
hci_alloc_dev+0x43/0x1d00 net/bluetooth/hci_core.c:3053
__vhci_create_device+0x101/0x5a0 drivers/bluetooth/hci_vhci.c:114
vhci_create_device drivers/bluetooth/hci_vhci.c:163 [inline]
vhci_get_user drivers/bluetooth/hci_vhci.c:219 [inline]
vhci_write+0x2d6/0x470 drivers/bluetooth/hci_vhci.c:299
call_write_iter include/linux/fs.h:1820 [inline]
new_sync_write fs/read_write.c:474 [inline]
__vfs_write+0x587/0x810 fs/read_write.c:487
vfs_write+0x20c/0x560 fs/read_write.c:549
ksys_write+0x14f/0x2d0 fs/read_write.c:599
__do_sys_write fs/read_write.c:611 [inline]
__se_sys_write fs/read_write.c:608 [inline]
__x64_sys_write+0x73/0xb0 fs/read_write.c:608
do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 9035:
save_stack+0x45/0xd0 mm/kasan/kasan.c:448
set_track mm/kasan/kasan.c:460 [inline]
__kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521
kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528
__cache_free mm/slab.c:3503 [inline]
kfree+0xcf/0x220 mm/slab.c:3822
bt_host_release+0x19/0x30 net/bluetooth/hci_sysfs.c:86
device_release+0x7b/0x210 drivers/base/core.c:892
kobject_cleanup lib/kobject.c:662 [inline]
kobject_release lib/kobject.c:691 [inline]
kref_put include/linux/kref.h:70 [inline]
kobject_put+0x193/0x290 lib/kobject.c:708
put_device+0x20/0x30 drivers/base/core.c:2082
hci_free_dev+0x19/0x20 net/bluetooth/hci_core.c:3145
vhci_release+0x7e/0xf0 drivers/bluetooth/hci_vhci.c:355
__fput+0x2dd/0x8b0 fs/file_table.c:278
____fput+0x16/0x20 fs/file_table.c:309
task_work_run+0x145/0x1c0 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:193 [inline]
exit_to_usermode_loop+0x273/0x2c0 arch/x86/entry/common.c:167
prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline]
syscall_return_slowpath arch/x86/entry/common.c:271 [inline]
do_syscall_64+0x53d/0x620 arch/x86/entry/common.c:296
entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff888080ac1e00
which belongs to the cache kmalloc-8192 of size 8192
The buggy address is located 4192 bytes inside of
8192-byte region [ffff888080ac1e00, ffff888080ac3e00)
The buggy address belongs to the page:
page:ffffea000202b000 count:1 mapcount:0 mapping:ffff88812c315080 index:0x0
compound_mapcount: 0
flags: 0xfffe0000008100(slab|head)
raw: 00fffe0000008100 ffffea000248ec08 ffffea00025d7908 ffff88812c315080
raw: 0000000000000000 ffff888080ac1e00 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff888080ac2d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888080ac2d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ffff888080ac2e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888080ac2e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888080ac2f00: 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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[syzbot]

syzbot suspects this issue was fixed by commit:

commit 3719acc161d5c1ce09912cc1c9eddc2c5faa3c66
Author: Tetsuo Handa <penguin...@i-love.sakura.ne.jp>
Date: Wed Aug 4 10:26:56 2021 +0000

Bluetooth: defer cleanup of resources in hci_unregister_dev()

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=14471399300000
start commit: 54b4fa6d3955 Linux 4.19.113
git tree: linux-4.19.y
kernel config: https://syzkaller.appspot.com/x/.config?x=7b1a0bc5526ebc49
dashboard link: https://syzkaller.appspot.com/bug?extid=bdbdd849903b8659f6ea
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14349a9de00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11ab06f3e00000

If the result looks correct, please mark the issue as fixed by replying with:

#syz fix: Bluetooth: defer cleanup of resources in hci_unregister_dev()

For information about bisection process see: https://goo.gl/tpsmEJ#bisection