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BUG: KASAN: slab-out-of-bounds in string_nocheck lib/vsprintf.c:642 [inline]
BUG: KASAN: slab-out-of-bounds in string+0x204/0x290 lib/vsprintf.c:724
Read of size 1 at addr ffff88802acb40a1 by task syz.3.221/4997

CPU: 0 PID: 4997 Comm: syz.3.221 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 print_address_description+0x60/0x2d0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:434 [inline]
 kasan_report+0xdf/0x130 mm/kasan/report.c:451
 string_nocheck lib/vsprintf.c:642 [inline]
 string+0x204/0x290 lib/vsprintf.c:724
 vsnprintf+0x10db/0x1c20 lib/vsprintf.c:2811
 va_format lib/vsprintf.c:1713 [inline]
 pointer+0x7b2/0xc60 lib/vsprintf.c:2448
 vsnprintf+0xd7c/0x1c20 lib/vsprintf.c:2815
 vprintk_store+0x378/0x11b0 kernel/printk/printk.c:2164
 vprintk_emit+0x85/0x150 kernel/printk/printk.c:2258
 _printk+0xda/0x130 kernel/printk/printk.c:2299
 __dynamic_pr_debug+0x196/0x240 lib/dynamic_debug.c:619
 nfc_llcp_wks_sap net/nfc/llcp_core.c:344 [inline]
 nfc_llcp_get_sdp_ssap+0x3c1/0x3f0 net/nfc/llcp_core.c:420
 llcp_sock_bind+0x3a2/0x770 net/nfc/llcp_sock.c:117
 __sys_bind+0x2e9/0x3e0 net/socket.c:1730
 __do_sys_bind net/socket.c:1741 [inline]
 __se_sys_bind net/socket.c:1739 [inline]
 __x64_sys_bind+0x76/0x80 net/socket.c:1739
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f8660ce2159
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f865ef19028 EFLAGS: 00000246 ORIG_RAX: 0000000000000031
RAX: ffffffffffffffda RBX: 00007f8660f6a090 RCX: 00007f8660ce2159
RDX: 0000000000000060 RSI: 0000200000000280 RDI: 0000000000000004
RBP: 00007f8660d7906b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8660f6a128 R14: 00007f8660f6a090 R15: 00007ffea0c1fe18
 </TASK>

Allocated by task 4997:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:434 [inline]
 ____kasan_kmalloc mm/kasan/common.c:513 [inline]
 __kasan_kmalloc+0xaf/0xe0 mm/kasan/common.c:522
 kmemdup+0x22/0x50 mm/util.c:128
 llcp_sock_bind+0x360/0x770 net/nfc/llcp_sock.c:107
 __sys_bind+0x2e9/0x3e0 net/socket.c:1730
 __do_sys_bind net/socket.c:1741 [inline]
 __se_sys_bind net/socket.c:1739 [inline]
 __x64_sys_bind+0x76/0x80 net/socket.c:1739
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

The buggy address belongs to the object at ffff88802acb4080
 which belongs to the cache kmalloc-64 of size 64
The buggy address is located 33 bytes inside of
 64-byte region [ffff88802acb4080, ffff88802acb40c0)
The buggy address belongs to the page:
page:ffffea0000ab2d00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2acb4
flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000200 ffffea0000925d40 0000001600000005 ffff888016c41640
raw: 0000000000000000 0000000080200020 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 0x12cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY), pid 1183, ts 18404716018, free_ts 0
 prep_new_page mm/page_alloc.c:2426 [inline]
 get_page_from_freelist+0x24f6/0x2670 mm/page_alloc.c:4192
 __alloc_pages+0x1ee/0x480 mm/page_alloc.c:5501
 alloc_slab_page mm/slub.c:1780 [inline]
 allocate_slab mm/slub.c:1917 [inline]
 new_slab+0xc0/0x4b0 mm/slub.c:1980
 ___slab_alloc+0x807/0xdd0 mm/slub.c:3013
 __slab_alloc mm/slub.c:3100 [inline]
 slab_alloc_node mm/slub.c:3191 [inline]
 __kmalloc_node+0x142/0x3a0 mm/slub.c:4456
 kmalloc_node include/linux/slab.h:630 [inline]
 __vmalloc_area_node mm/vmalloc.c:2918 [inline]
 __vmalloc_node_range+0x2dd/0x8b0 mm/vmalloc.c:3037
 alloc_thread_stack_node kernel/fork.c:247 [inline]
 dup_task_struct+0x41a/0xbc0 kernel/fork.c:900
 copy_process+0x61f/0x3e70 kernel/fork.c:2127
 kernel_clone+0x23f/0x990 kernel/fork.c:2682
 kernel_thread+0xfa/0x160 kernel/fork.c:2734
 call_usermodehelper_exec_work+0x58/0x220 kernel/umh.c:174
 process_one_work+0x867/0xff0 kernel/workqueue.c:2310
 worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
page_owner free stack trace missing

Memory state around the buggy address:
 ffff88802acb3f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88802acb4000: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
>ffff88802acb4080: 00 00 00 00 01 fc fc fc fc fc fc fc fc fc fc fc
                               ^
 ffff88802acb4100: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
 ffff88802acb4180: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc
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