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BUG: KASAN: use-after-free in l2cap_chan_close+0x46/0xae0 net/bluetooth/l2cap_core.c:790
Read of size 8 at addr ffff88809768a000 by task kworker/0:2/2547

CPU: 0 PID: 2547 Comm: kworker/0:2 Not tainted 5.8.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events do_enable_set
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1f0/0x31e lib/dump_stack.c:118
 print_address_description+0x66/0x5a0 mm/kasan/report.c:383
 __kasan_report mm/kasan/report.c:513 [inline]
 kasan_report+0x132/0x1d0 mm/kasan/report.c:530
 l2cap_chan_close+0x46/0xae0 net/bluetooth/l2cap_core.c:790
 do_enable_set+0x662/0x900 net/bluetooth/6lowpan.c:1082
 process_one_work+0x789/0xfc0 kernel/workqueue.c:2269
 worker_thread+0xaa4/0x1460 kernel/workqueue.c:2415
 kthread+0x37e/0x3a0 drivers/block/aoe/aoecmd.c:1234
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293

Allocated by task 23:
 save_stack mm/kasan/common.c:48 [inline]
 set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc+0x103/0x140 mm/kasan/common.c:494
 kmem_cache_alloc_trace+0x234/0x300 mm/slab.c:3551
 kmalloc include/linux/slab.h:555 [inline]
 kzalloc include/linux/slab.h:669 [inline]
 l2cap_chan_create+0x4c/0x320 net/bluetooth/l2cap_core.c:450
 chan_create net/bluetooth/6lowpan.c:648 [inline]
 bt_6lowpan_listen net/bluetooth/6lowpan.c:967 [inline]
 do_enable_set+0x6a7/0x900 net/bluetooth/6lowpan.c:1086
 process_one_work+0x789/0xfc0 kernel/workqueue.c:2269
 worker_thread+0xaa4/0x1460 kernel/workqueue.c:2415
 kthread+0x37e/0x3a0 drivers/block/aoe/aoecmd.c:1234
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293

Freed by task 23:
 save_stack mm/kasan/common.c:48 [inline]
 set_track mm/kasan/common.c:56 [inline]
 kasan_set_free_info mm/kasan/common.c:316 [inline]
 __kasan_slab_free+0x114/0x170 mm/kasan/common.c:455
 __cache_free mm/slab.c:3426 [inline]
 kfree+0x10a/0x220 mm/slab.c:3757
 do_enable_set+0x66e/0x900 net/bluetooth/6lowpan.c:1083
 process_one_work+0x789/0xfc0 kernel/workqueue.c:2269
 worker_thread+0xaa4/0x1460 kernel/workqueue.c:2415
 kthread+0x37e/0x3a0 drivers/block/aoe/aoecmd.c:1234
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293

The buggy address belongs to the object at ffff88809768a000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 0 bytes inside of
 2048-byte region [ffff88809768a000, ffff88809768a800)
The buggy address belongs to the page:
page:ffffea00025da280 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea00029e4648 ffffea00025c11c8 ffff8880aa400e00
raw: 0000000000000000 ffff88809768a000 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888097689f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888097689f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88809768a000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff88809768a080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88809768a100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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