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BUG: KASAN: stack-out-of-bounds in skb_put_data include/linux/skbuff.h:2800 [inline]
BUG: KASAN: stack-out-of-bounds in l2cap_build_cmd net/bluetooth/l2cap_core.c:3003 [inline]
BUG: KASAN: stack-out-of-bounds in l2cap_send_cmd+0x2a3/0xb90 net/bluetooth/l2cap_core.c:954
Read of size 26 at addr ffffc90003a67500 by task kworker/u9:4/5826

CPU: 0 UID: 0 PID: 5826 Comm: kworker/u9:4 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Workqueue: hci0 hci_rx_work
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xba/0x230 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x264/0x2c0 mm/kasan/generic.c:200
 __asan_memcpy+0x29/0x70 mm/kasan/shadow.c:105
 skb_put_data include/linux/skbuff.h:2800 [inline]
 l2cap_build_cmd net/bluetooth/l2cap_core.c:3003 [inline]
 l2cap_send_cmd+0x2a3/0xb90 net/bluetooth/l2cap_core.c:954
 l2cap_ecred_conn_req net/bluetooth/l2cap_core.c:5208 [inline]
 l2cap_le_sig_cmd net/bluetooth/l2cap_core.c:5510 [inline]
 l2cap_le_sig_channel net/bluetooth/l2cap_core.c:5568 [inline]
 l2cap_recv_frame+0xc032/0x10240 net/bluetooth/l2cap_core.c:6913
 l2cap_recv_acldata+0x7e9/0x13e0 net/bluetooth/l2cap_core.c:7637
 hci_acldata_packet net/bluetooth/hci_core.c:3855 [inline]
 hci_rx_work+0x4f9/0x1030 net/bluetooth/hci_core.c:4082
 process_one_work kernel/workqueue.c:3275 [inline]
 process_scheduled_works+0xb02/0x1830 kernel/workqueue.c:3358
 worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

The buggy address belongs to stack of task kworker/u9:4/5826
 and is located at offset 128 in frame:
 l2cap_recv_frame+0x0/0x10240 include/linux/skbuff.h:-1

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.i229.i.i'
 [304, 312) 'buf.i222.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 0xffffc90003a60000 allocated at copy_process+0x508/0x3cf0 kernel/fork.c:2050
The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x679af
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 0000000000000000 dead000000000122 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 67023525297, free_ts 66975418192
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x231/0x280 mm/page_alloc.c:1889
 prep_new_page mm/page_alloc.c:1897 [inline]
 get_page_from_freelist+0x24dc/0x2580 mm/page_alloc.c:3962
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5250
 __alloc_pages_noprof+0xa/0x30 mm/page_alloc.c:5284
 __alloc_pages_node_noprof include/linux/gfp.h:289 [inline]
 alloc_pages_node_noprof include/linux/gfp.h:316 [inline]
 vm_area_alloc_pages mm/vmalloc.c:3664 [inline]
 __vmalloc_area_node mm/vmalloc.c:3876 [inline]
 __vmalloc_node_range_noprof+0x7be/0x1730 mm/vmalloc.c:4064
 __vmalloc_node_noprof+0xc2/0x100 mm/vmalloc.c:4124
 alloc_thread_stack_node kernel/fork.c:355 [inline]
 dup_task_struct+0x228/0x9a0 kernel/fork.c:924
 copy_process+0x508/0x3cf0 kernel/fork.c:2050
 kernel_clone+0x248/0x8e0 kernel/fork.c:2654
 kernel_thread+0x13f/0x1b0 kernel/fork.c:2715
 create_kthread kernel/kthread.c:459 [inline]
 kthreadd+0x4ec/0x6e0 kernel/kthread.c:817
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
page last free pid 5819 tgid 5819 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1433 [inline]
 __free_frozen_pages+0xc2b/0xdb0 mm/page_alloc.c:2978
 __slab_free+0x263/0x2b0 mm/slub.c:5576
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x97/0x100 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4542 [inline]
 slab_alloc_node mm/slub.c:4869 [inline]
 __kmalloc_cache_noprof+0x2ba/0x660 mm/slub.c:5378
 kmalloc_noprof include/linux/slab.h:950 [inline]
 kzalloc_noprof include/linux/slab.h:1188 [inline]
 kcov_open+0x25/0x90 kernel/kcov.c:530
 open_proxy_open+0x346/0x4a0 fs/debugfs/file.c:317
 do_dentry_open+0x785/0x14e0 fs/open.c:949
 vfs_open+0x3b/0x340 fs/open.c:1081
 do_open fs/namei.c:4671 [inline]
 path_openat+0x2e08/0x3860 fs/namei.c:4830
 do_file_open+0x23e/0x4a0 fs/namei.c:4859
 do_sys_openat2+0x113/0x200 fs/open.c:1366
 do_sys_open fs/open.c:1372 [inline]
 __do_sys_openat fs/open.c:1388 [inline]
 __se_sys_openat fs/open.c:1383 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1383
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffffc90003a67400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc90003a67480: f1 f1 f1 f1 f8 f2 f8 f8 f8 f8 f8 f2 f2 f2 f2 f2
>ffffc90003a67500: 00 00 02 f2 f2 f2 f2 f2 f8 f8 f2 f2 f8 f2 f8 f2
                         ^
 ffffc90003a67580: f8 f2 f8 f2 f8 f2 f8 f2 f2 f2 f8 f8 f2 f2 f8 f2
 ffffc90003a67600: f8 f8 f2 f2 f8 f8 f8 f8 f8 f8 f8 f8 f2 f2 f2 f2
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