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BUG: KASAN: use-after-free in __lock_acquire+0x40d0/0x5570 kernel/locking/lockdep.c:4296
Read of size 8 at addr ffff888092dc90a0 by task kworker/1:4/8260

CPU: 1 PID: 8260 Comm: kworker/1:4 Not tainted 5.9.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events l2cap_chan_timeout
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x198/0x1fd lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xae/0x497 mm/kasan/report.c:383
 __kasan_report mm/kasan/report.c:513 [inline]
 kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530
 __lock_acquire+0x40d0/0x5570 kernel/locking/lockdep.c:4296
 lock_acquire+0x1f3/0xae0 kernel/locking/lockdep.c:5006
 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline]
 _raw_spin_lock_bh+0x2f/0x40 kernel/locking/spinlock.c:175
 spin_lock_bh include/linux/spinlock.h:359 [inline]
 lock_sock_nested+0x3b/0x110 net/core/sock.c:3048
 l2cap_sock_teardown_cb+0x88/0x400 net/bluetooth/l2cap_sock.c:1520
 l2cap_chan_del+0xad/0x1300 net/bluetooth/l2cap_core.c:618
 l2cap_chan_close+0x118/0xb10 net/bluetooth/l2cap_core.c:823
 l2cap_chan_timeout+0x173/0x450 net/bluetooth/l2cap_core.c:436
 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415
 kthread+0x3b5/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

Allocated by task 10361:
 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
 __do_kmalloc mm/slab.c:3655 [inline]
 __kmalloc+0x1b0/0x310 mm/slab.c:3664
 kmalloc include/linux/slab.h:559 [inline]
 sk_prot_alloc+0x17a/0x300 net/core/sock.c:1685
 sk_alloc+0x32/0xbd0 net/core/sock.c:1739
 l2cap_sock_alloc.constprop.0+0x31/0x230 net/bluetooth/l2cap_sock.c:1790
 l2cap_sock_create+0x110/0x1b0 net/bluetooth/l2cap_sock.c:1836
 bt_sock_create+0x154/0x2a0 net/bluetooth/af_bluetooth.c:130
 __sock_create+0x3ca/0x740 net/socket.c:1427
 sock_create net/socket.c:1478 [inline]
 __sys_socket+0xef/0x200 net/socket.c:1520
 __do_sys_socket net/socket.c:1529 [inline]
 __se_sys_socket net/socket.c:1527 [inline]
 __x64_sys_socket+0x6f/0xb0 net/socket.c:1527
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 10361:
 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:3418 [inline]
 kfree+0x10e/0x2b0 mm/slab.c:3756
 sk_prot_free net/core/sock.c:1722 [inline]
 __sk_destruct+0x63b/0x860 net/core/sock.c:1807
 sk_destruct+0xbd/0xe0 net/core/sock.c:1822
 __sk_free+0xef/0x3d0 net/core/sock.c:1833
 sk_free+0x78/0xa0 net/core/sock.c:1844
 sock_put include/net/sock.h:1781 [inline]
 l2cap_sock_kill+0x14e/0x180 net/bluetooth/l2cap_sock.c:1219
 l2cap_sock_release+0x171/0x1d0 net/bluetooth/l2cap_sock.c:1389
 __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+0x82/0x2520 arch/x86/kernel/signal.c:811
 exit_to_user_mode_loop kernel/entry/common.c:136 [inline]
 exit_to_user_mode_prepare+0x1ae/0x200 kernel/entry/common.c:167
 syscall_exit_to_user_mode+0x7e/0x2e0 kernel/entry/common.c:242
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff888092dc9000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 160 bytes inside of
 2048-byte region [ffff888092dc9000, ffff888092dc9800)
The buggy address belongs to the page:
page:0000000047ef5f8d refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x92dc9
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea00027c0648 ffffea00029feb48 ffff8880aa040800
raw: 0000000000000000 ffff888092dc9000 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888092dc8f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888092dc9000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888092dc9080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                               ^
 ffff888092dc9100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888092dc9180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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