KASAN: use-after-free Read in sco_chan_del

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: a804ab08 Add linux-next specific files for 20201006
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=1073270b900000
kernel config: https://syzkaller.appspot.com/x/.config?x=26c1b4cc4a62ccb
dashboard link: https://syzkaller.appspot.com/bug?extid=1df6a63e69a359c8b517
compiler: gcc (GCC) 10.1.0-syz 20200507

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

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+1df6a6...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: use-after-free in hci_conn_drop include/net/bluetooth/hci_core.h:1145 [inline]
BUG: KASAN: use-after-free in hci_conn_drop include/net/bluetooth/hci_core.h:1115 [inline]
BUG: KASAN: use-after-free in sco_chan_del+0x400/0x430 net/bluetooth/sco.c:149
Read of size 8 at addr ffff88804d29c918 by task syz-executor.2/27575

CPU: 0 PID: 27575 Comm: syz-executor.2 Not tainted 5.9.0-rc8-next-20201006-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+0x198/0x1fb lib/dump_stack.c:118
print_address_description.constprop.0.cold+0xae/0x497 mm/kasan/report.c:385
__kasan_report mm/kasan/report.c:545 [inline]
kasan_report.cold+0x1f/0x37 mm/kasan/report.c:562
hci_conn_drop include/net/bluetooth/hci_core.h:1145 [inline]
hci_conn_drop include/net/bluetooth/hci_core.h:1115 [inline]
sco_chan_del+0x400/0x430 net/bluetooth/sco.c:149
__sco_sock_close+0x16e/0x5b0 net/bluetooth/sco.c:434
sco_sock_close net/bluetooth/sco.c:448 [inline]
sco_sock_release+0x69/0x290 net/bluetooth/sco.c:1059
__sock_release+0xcd/0x280 net/socket.c:596
sock_close+0x18/0x20 net/socket.c:1277
__fput+0x285/0x920 fs/file_table.c:281
task_work_run+0xdd/0x190 kernel/task_work.c:141
get_signal+0xd89/0x1f00 kernel/signal.c:2561
arch_do_signal+0x82/0x2470 arch/x86/kernel/signal.c:811
exit_to_user_mode_loop kernel/entry/common.c:161 [inline]
exit_to_user_mode_prepare+0x194/0x1f0 kernel/entry/common.c:192
syscall_exit_to_user_mode+0x7a/0x2c0 kernel/entry/common.c:267
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45de29
Code: 0d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 db b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fabeda51c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: fffffffffffffffc RBX: 0000000000002200 RCX: 000000000045de29
RDX: 0000000000000008 RSI: 0000000020000080 RDI: 0000000000000006
RBP: 000000000118c158 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118c124
R13: 00007ffdb3c9529f R14: 00007fabeda529c0 R15: 000000000118c124

Allocated by task 27575:
kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48
kasan_set_track mm/kasan/common.c:56 [inline]
__kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:461
kmem_cache_alloc_trace+0x1a0/0x480 mm/slab.c:3552
kmalloc include/linux/slab.h:554 [inline]
kzalloc include/linux/slab.h:666 [inline]
hci_conn_add+0x53/0x1330 net/bluetooth/hci_conn.c:525
hci_connect_sco+0x356/0x860 net/bluetooth/hci_conn.c:1283
sco_connect net/bluetooth/sco.c:241 [inline]
sco_sock_connect+0x308/0x980 net/bluetooth/sco.c:588
__sys_connect_file+0x155/0x1a0 net/socket.c:1852
__sys_connect+0x161/0x190 net/socket.c:1869
__do_sys_connect net/socket.c:1879 [inline]
__se_sys_connect net/socket.c:1876 [inline]
__x64_sys_connect+0x6f/0xb0 net/socket.c:1876
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 26665:
kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48
kasan_set_track+0x1c/0x30 mm/kasan/common.c:56
kasan_set_free_info+0x1b/0x30 mm/kasan/generic.c:355
__kasan_slab_free+0xd8/0x120 mm/kasan/common.c:422
__cache_free mm/slab.c:3420 [inline]
kfree+0x10e/0x2a0 mm/slab.c:3758
device_release+0x9f/0x240 drivers/base/core.c:1808
kobject_cleanup lib/kobject.c:705 [inline]
kobject_release lib/kobject.c:736 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x171/0x270 lib/kobject.c:753
put_device+0x1b/0x30 drivers/base/core.c:3037
hci_conn_del+0x27e/0x6a0 net/bluetooth/hci_conn.c:645
hci_conn_hash_flush+0x189/0x220 net/bluetooth/hci_conn.c:1558
hci_dev_do_close+0x5c6/0x1080 net/bluetooth/hci_core.c:1770
hci_unregister_dev+0x214/0xe90 net/bluetooth/hci_core.c:3827
vhci_release+0x70/0xe0 drivers/bluetooth/hci_vhci.c:340
__fput+0x285/0x920 fs/file_table.c:281
task_work_run+0xdd/0x190 kernel/task_work.c:141
exit_task_work include/linux/task_work.h:25 [inline]
do_exit+0xb23/0x2930 kernel/exit.c:806
do_group_exit+0x125/0x310 kernel/exit.c:903
get_signal+0x428/0x1f00 kernel/signal.c:2757
arch_do_signal+0x82/0x2470 arch/x86/kernel/signal.c:811
exit_to_user_mode_loop kernel/entry/common.c:161 [inline]
exit_to_user_mode_prepare+0x194/0x1f0 kernel/entry/common.c:192
syscall_exit_to_user_mode+0x7a/0x2c0 kernel/entry/common.c:267
entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff88804d29c000
which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 2328 bytes inside of
4096-byte region [ffff88804d29c000, ffff88804d29d000)
The buggy address belongs to the page:
page:0000000084eedba7 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x4d29c
head:0000000084eedba7 order:1 compound_mapcount:0
flags: 0xfffe0000010200(slab|head)
raw: 00fffe0000010200 ffffea00012af708 ffffea0001001308 ffff8880aa040900
raw: 0000000000000000 ffff88804d29c000 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff88804d29c800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88804d29c880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88804d29c900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88804d29c980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88804d29ca00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.