audit: type=1400 audit(1589773311.990:8): avc:  denied  { execmem } for  pid=6466 comm="syz-executor638" scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:system_r:kernel_t:s0 tclass=process permissive=1
==================================================================
BUG: KASAN: use-after-free in l2cap_chan_close+0x586/0x810 net/bluetooth/l2cap_core.c:727
Read of size 1 at addr ffff88808e5ad320 by task kworker/0:1/14

CPU: 0 PID: 14 Comm: kworker/0:1 Not tainted 4.19.123-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+0x188/0x20d lib/dump_stack.c:118
 print_address_description.cold+0x7c/0x212 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+0x88/0x2b9 mm/kasan/report.c:396
 l2cap_chan_close+0x586/0x810 net/bluetooth/l2cap_core.c:727
 do_enable_set+0x4c5/0x8d0 net/bluetooth/6lowpan.c:1086
 process_one_work+0x91f/0x1640 kernel/workqueue.c:2155
 worker_thread+0x96/0xe20 kernel/workqueue.c:2298
 kthread+0x34a/0x420 kernel/kthread.c:246
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415

Allocated by task 14:
 set_track mm/kasan/kasan.c:460 [inline]
 kasan_kmalloc mm/kasan/kasan.c:553 [inline]
 kasan_kmalloc+0xbf/0xe0 mm/kasan/kasan.c:531
 kmem_cache_alloc_trace+0x14d/0x7a0 mm/slab.c:3625
 kmalloc include/linux/slab.h:515 [inline]
 kzalloc include/linux/slab.h:709 [inline]
 l2cap_chan_create+0x40/0x380 net/bluetooth/l2cap_core.c:441
 chan_create+0xc/0xd0 net/bluetooth/6lowpan.c:652
 bt_6lowpan_listen net/bluetooth/6lowpan.c:971 [inline]
 do_enable_set+0x507/0x8d0 net/bluetooth/6lowpan.c:1090
 process_one_work+0x91f/0x1640 kernel/workqueue.c:2155
 worker_thread+0x96/0xe20 kernel/workqueue.c:2298
 kthread+0x34a/0x420 kernel/kthread.c:246
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415

Freed by task 24:
 set_track mm/kasan/kasan.c:460 [inline]
 __kasan_slab_free+0xf7/0x140 mm/kasan/kasan.c:521
 __cache_free mm/slab.c:3503 [inline]
 kfree+0xce/0x220 mm/slab.c:3822
 kref_put include/linux/kref.h:70 [inline]
 l2cap_chan_put+0x35/0x40 net/bluetooth/l2cap_core.c:493
 do_enable_set+0x4d1/0x8d0 net/bluetooth/6lowpan.c:1087
 process_one_work+0x91f/0x1640 kernel/workqueue.c:2155
 worker_thread+0x96/0xe20 kernel/workqueue.c:2298
 kthread+0x34a/0x420 kernel/kthread.c:246
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415

The buggy address belongs to the object at ffff88808e5ad300
 which belongs to the cache kmalloc-2048 of size 2048
The buggy address is located 32 bytes inside of
 2048-byte region [ffff88808e5ad300, ffff88808e5adb00)
The buggy address belongs to the page:
page:ffffea0002396b00 count:1 mapcount:0 mapping:ffff88812c39cc40 index:0x0 compound_mapcount: 0
flags: 0xfffe0000008100(slab|head)
raw: 00fffe0000008100 ffffea0002396c08 ffffea0002998188 ffff88812c39cc40
raw: 0000000000000000 ffff88808e5ac200 0000000100000003 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88808e5ad200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88808e5ad280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88808e5ad300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                               ^
 ffff88808e5ad380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88808e5ad400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================