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BUG: KASAN: stack-out-of-bounds in l2cap_send_cmd+0x28d/0xb80
Read of size 20 at addr ffffc90000be7520 by task kworker/u11:0/54

CPU: 1 UID: 0 PID: 54 Comm: kworker/u11:0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Workqueue: hci0 hci_rx_work
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150
 print_report+0xba/0x230
 kasan_report+0x117/0x150
 kasan_check_range+0x264/0x2c0
 __asan_memcpy+0x29/0x70
 l2cap_send_cmd+0x28d/0xb80
 l2cap_recv_frame+0xbf84/0x10150
 l2cap_recv_acldata+0x7d3/0x13b0
 hci_rx_work+0x4f9/0x1010
 process_scheduled_works+0xa2f/0x1470
 worker_thread+0xa44/0xfb0
 kthread+0x388/0x470
 ret_from_fork+0x51e/0xb90
 ret_from_fork_asm+0x1a/0x30
 </TASK>

The buggy address belongs to stack of task kworker/u11:0/54
 and is located at offset 128 in frame:
 l2cap_recv_frame+0x0/0x10150

This frame has 26 objects:
 [32, 34) 'rsp.i241.i.i'
 [48, 88) 'chan.i.i.i'
 [128, 146) 'pdu_u.i.i.i'
 [192, 202) 'rsp.i94.i.i'
 [224, 226) 'rsp.i.i.i111'
 [240, 242) 'rej.i'
 [256, 258) 'rej.i145.i'
 [272, 274) 'rej.i143.i'
 [288, 290) 'req.i230.i.i'
 [304, 312) 'buf.i223.i.i'
 [336, 348) 'buf29.i.i.i'
 [368, 372) 'rsp49.i.i.i'
 [384, 393) 'rfc.i.i118.i.i'
 [416, 480) 'buf.i119.i.i'
 [512, 576) 'req.i120.i.i'
 [608, 617) 'rfc.i.i.i.i'
 [640, 656) 'efs.i.i.i.i'
 [672, 678) 'rej.i371.i.i.i'
 [704, 710) 'rej.i.i.i.i'
 [736, 800) 'rsp.i.i.i'
 [832, 896) 'buf.i.i.i'
 [928, 1056) 'req.i.i.i'
 [1088, 1096) 'rsp.i.i.i.i'
 [1120, 1122) 'info.i.i.i.i'
 [1136, 1264) 'buf.i.i.i.i'
 [1296, 1298) 'rej.i.i'

The buggy address belongs to a 8-page vmalloc region starting at 0xffffc90000be0000 allocated at copy_process+0x50f/0x3d00
The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1072df
flags: 0x17ff00000000000(node=0|zone=2|lastcpupid=0x7ff)
raw: 017ff00000000000 ffffea00041cb7c8 ffffea00041cb7c8 0000000000000000
raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x29c2(GFP_NOWAIT|__GFP_HIGHMEM|__GFP_IO|__GFP_FS|__GFP_ZERO), pid 2, tgid 2 (kthreadd), ts 3852803570, free_ts 0
 post_alloc_hook+0x231/0x280
 get_page_from_freelist+0x2503/0x25a0
 __alloc_frozen_pages_noprof+0x18d/0x380
 alloc_pages_mpol+0x22b/0x390
 alloc_pages_noprof+0xa8/0x190
 __vmalloc_node_range_noprof+0x7ac/0x1830
 __vmalloc_node_noprof+0xc2/0x100
 dup_task_struct+0x289/0x9c0
 copy_process+0x50f/0x3d00
 kernel_clone+0x248/0x8e0
 kernel_thread+0x13f/0x1b0
 kthreadd+0x4ec/0x6e0
 ret_from_fork+0x51e/0xb90
 ret_from_fork_asm+0x1a/0x30
page_owner free stack trace missing

Memory state around the buggy address:
 ffffc90000be7400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc90000be7480: 00 00 00 00 f1 f1 f1 f1 f8 f2 f8 f8 f8 f8 f8 f2
>ffffc90000be7500: f2 f2 f2 f2 00 00 02 f2 f2 f2 f2 f2 f8 f8 f2 f2
                                     ^
 ffffc90000be7580: f8 f2 f8 f2 f8 f2 f8 f2 f8 f2 f8 f2 f2 f2 f8 f8
 ffffc90000be7600: f2 f2 f8 f2 f8 f8 f2 f2 f8 f8 f8 f8 f8 f8 f8 f8
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