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BUG: KASAN: use-after-free in hci_cmd_timeout+0x203/0x210 net/bluetooth/hci_core.c:2756
Read of size 2 at addr ffff888026399c08 by task kworker/0:11/11901

CPU: 0 PID: 11901 Comm: kworker/0:11 Not tainted 5.11.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events hci_cmd_timeout
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x107/0x163 lib/dump_stack.c:120
 print_address_description.constprop.0.cold+0x5b/0x2f8 mm/kasan/report.c:230
 __kasan_report mm/kasan/report.c:396 [inline]
 kasan_report.cold+0x79/0xd5 mm/kasan/report.c:413
 hci_cmd_timeout+0x203/0x210 net/bluetooth/hci_core.c:2756
 process_one_work+0x98d/0x15f0 kernel/workqueue.c:2275
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2421
 kthread+0x3b1/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

Allocated by task 8489:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:401 [inline]
 ____kasan_kmalloc.constprop.0+0x82/0xa0 mm/kasan/common.c:429
 kasan_slab_alloc include/linux/kasan.h:205 [inline]
 slab_post_alloc_hook mm/slab.h:512 [inline]
 slab_alloc_node mm/slub.c:2891 [inline]
 __kmalloc_node_track_caller+0x1e0/0x3f0 mm/slub.c:4495
 __kmalloc_reserve net/core/skbuff.c:142 [inline]
 __alloc_skb+0xae/0x5a0 net/core/skbuff.c:210
 alloc_skb include/linux/skbuff.h:1099 [inline]
 bt_skb_alloc include/net/bluetooth/bluetooth.h:389 [inline]
 hci_prepare_cmd+0x2f/0x290 net/bluetooth/hci_request.c:292
 hci_req_add_ev+0xdc/0x220 net/bluetooth/hci_request.c:326
 __hci_cmd_sync_ev+0x121/0x670 net/bluetooth/hci_request.c:138
 btintel_enter_mfg+0x2a/0x90 drivers/bluetooth/btintel.c:71
 ag6xx_setup+0xfc/0x790 drivers/bluetooth/hci_ag6xx.c:165
 hci_uart_setup+0x1b1/0x480 drivers/bluetooth/hci_ldisc.c:424
 hci_dev_do_open+0x3e1/0x1a00 net/bluetooth/hci_core.c:1497
 hci_power_on+0x133/0x650 net/bluetooth/hci_core.c:2245
 process_one_work+0x98d/0x15f0 kernel/workqueue.c:2275
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2421
 kthread+0x3b1/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

Freed by task 8489:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
 kasan_set_track+0x1c/0x30 mm/kasan/common.c:46
 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:356
 ____kasan_slab_free+0xe1/0x110 mm/kasan/common.c:362
 kasan_slab_free include/linux/kasan.h:188 [inline]
 slab_free_hook mm/slub.c:1547 [inline]
 slab_free_freelist_hook+0x5d/0x150 mm/slub.c:1580
 slab_free mm/slub.c:3142 [inline]
 kfree+0xdb/0x3b0 mm/slub.c:4124
 skb_free_head net/core/skbuff.c:595 [inline]
 skb_release_data+0x6d9/0x910 net/core/skbuff.c:615
 skb_release_all net/core/skbuff.c:669 [inline]
 __kfree_skb net/core/skbuff.c:683 [inline]
 kfree_skb net/core/skbuff.c:701 [inline]
 kfree_skb+0x133/0x3f0 net/core/skbuff.c:695
 hci_dev_do_open+0xa4a/0x1a00 net/bluetooth/hci_core.c:1619
 hci_power_on+0x133/0x650 net/bluetooth/hci_core.c:2245
 process_one_work+0x98d/0x15f0 kernel/workqueue.c:2275
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2421
 kthread+0x3b1/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

The buggy address belongs to the object at ffff888026399c00
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 8 bytes inside of
 512-byte region [ffff888026399c00, ffff888026399e00)
The buggy address belongs to the page:
page:0000000028af3d5e refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x26398
head:0000000028af3d5e order:1 compound_mapcount:0
flags: 0xfff00000010200(slab|head)
raw: 00fff00000010200 0000000000000000 0000000500000001 ffff888010041280
raw: 0000000000000000 0000000000080008 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888026399b00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888026399b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888026399c00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                      ^
 ffff888026399c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888026399d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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