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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:2999 [inline]
BUG: KASAN: stack-out-of-bounds in l2cap_send_cmd+0x9a5/0xc80 net/bluetooth/l2cap_core.c:954
Read of size 26 at addr ffffc90004237a60 by task kworker/u9:5/5817

CPU: 0 UID: 0 PID: 5817 Comm: kworker/u9:5 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Workqueue: hci0 hci_rx_work
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0x156/0x4c9 mm/kasan/report.c:482
 kasan_report+0xdf/0x1e0 mm/kasan/report.c:595
 check_region_inline mm/kasan/generic.c:186 [inline]
 kasan_check_range+0x10f/0x1e0 mm/kasan/generic.c:200
 __asan_memcpy+0x23/0x60 mm/kasan/shadow.c:105
 skb_put_data include/linux/skbuff.h:2800 [inline]
 l2cap_build_cmd net/bluetooth/l2cap_core.c:2999 [inline]
 l2cap_send_cmd+0x9a5/0xc80 net/bluetooth/l2cap_core.c:954
 l2cap_ecred_conn_req net/bluetooth/l2cap_core.c:5214 [inline]
 l2cap_le_sig_cmd net/bluetooth/l2cap_core.c:5516 [inline]
 l2cap_le_sig_channel net/bluetooth/l2cap_core.c:5574 [inline]
 l2cap_recv_frame+0x6349/0x9f80 net/bluetooth/l2cap_core.c:6924
 l2cap_recv_acldata+0xe60/0x10a0 net/bluetooth/l2cap_core.c:7648
 hci_acldata_packet net/bluetooth/hci_core.c:3855 [inline]
 hci_rx_work+0x537/0xfc0 net/bluetooth/hci_core.c:4082
 process_one_work+0xa23/0x19a0 kernel/workqueue.c:3276
 process_scheduled_works kernel/workqueue.c:3359 [inline]
 worker_thread+0x5ef/0xe50 kernel/workqueue.c:3440
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x754/0xd80 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/u9:5/5817
 and is located at offset 160 in frame:
 l2cap_recv_frame+0x0/0x9f80 net/bluetooth/l2cap_core.c:1658

This frame has 10 objects:
 [48, 50) 'rsp'
 [64, 68) 'rsp'
 [80, 86) 'rej'
 [112, 122) 'rsp'
 [144, 148) 'rsp'
 [160, 178) 'pdu_u'
 [224, 264) 'chan'
 [304, 308) 'rx_func_to_event'
 [320, 328) 'buf'
 [352, 364) 'buf'

The buggy address belongs to a 8-page vmalloc region starting at 0xffffc90004230000 allocated at kernel_clone+0xfc/0x9a0 kernel/fork.c:2653
The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7b107
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 60643563301, free_ts 60626064950
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x153/0x170 mm/page_alloc.c:1889
 prep_new_page mm/page_alloc.c:1897 [inline]
 get_page_from_freelist+0x111d/0x3140 mm/page_alloc.c:3962
 __alloc_frozen_pages_noprof+0x27c/0x2ba0 mm/page_alloc.c:5250
 __alloc_pages_noprof+0xb/0x1b0 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+0xd29/0x1530 mm/vmalloc.c:4064
 __vmalloc_node_noprof+0xad/0xf0 mm/vmalloc.c:4124
 alloc_thread_stack_node kernel/fork.c:355 [inline]
 dup_task_struct kernel/fork.c:924 [inline]
 copy_process+0x5ec/0x7a40 kernel/fork.c:2050
 kernel_clone+0xfc/0x9a0 kernel/fork.c:2653
 kernel_thread+0xdb/0x120 kernel/fork.c:2714
 create_kthread kernel/kthread.c:459 [inline]
 kthreadd+0x498/0x7a0 kernel/kthread.c:817
 ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
page last free pid 5804 tgid 5804 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1433 [inline]
 __free_frozen_pages+0x7e1/0x10d0 mm/page_alloc.c:2978
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x47/0xe0 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x1a0/0x1f0 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:350
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4538 [inline]
 slab_alloc_node mm/slub.c:4866 [inline]
 __kmalloc_cache_noprof+0x243/0x6f0 mm/slub.c:5375
 kmalloc_noprof include/linux/slab.h:950 [inline]
 kzalloc_noprof include/linux/slab.h:1188 [inline]
 kset_create lib/kobject.c:965 [inline]
 kset_create_and_add+0x4d/0x190 lib/kobject.c:1008
 register_queue_kobjects net/core/net-sysfs.c:2106 [inline]
 netdev_register_kobject+0x1ef/0x3d0 net/core/net-sysfs.c:2362
 register_netdevice+0x12e0/0x2210 net/core/dev.c:11424
 register_netdev+0x34/0x50 net/core/dev.c:11540
 loopback_net_init+0x7a/0x170 drivers/net/loopback.c:218
 ops_init+0x1e2/0x5f0 net/core/net_namespace.c:137
 setup_net+0x118/0x3a0 net/core/net_namespace.c:446
 copy_net_ns+0x46f/0x7c0 net/core/net_namespace.c:581
 create_new_namespaces+0x3ea/0xac0 kernel/nsproxy.c:130
 unshare_nsproxy_namespaces+0xc3/0x1f0 kernel/nsproxy.c:226
 ksys_unshare+0x473/0xad0 kernel/fork.c:3173

Memory state around the buggy address:
 ffffc90004237900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc90004237980: 00 00 00 00 00 00 00 00 f1 f1 f1 f1 f1 f1 02 f2
>ffffc90004237a00: 04 f2 06 f2 f2 f2 00 02 f2 f2 04 f2 00 00 02 f2
                                                             ^
 ffffc90004237a80: f2 f2 f2 f2 00 00 00 00 00 f2 f2 f2 f2 f2 04 f2
 ffffc90004237b00: 00 f2 f2 f2 00 04 f3 f3 00 00 00 00 00 00 00 00
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