================================================================== 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 ffff888078fdf821 by task syz.6.589/6861 CPU: 1 PID: 6861 Comm: syz.6.589 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Call Trace: 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: 0033:0x7f0659457159 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:00007f06576af028 EFLAGS: 00000246 ORIG_RAX: 0000000000000031 RAX: ffffffffffffffda RBX: 00007f06596defa0 RCX: 00007f0659457159 RDX: 0000000000000060 RSI: 0000200000000080 RDI: 0000000000000004 RBP: 00007f06594ee06b R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f06596df038 R14: 00007f06596defa0 R15: 00007ffd881dbaf8 Allocated by task 6861: 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 ffff888078fdf820 which belongs to the cache kmalloc-8 of size 8 The buggy address is located 1 bytes inside of 8-byte region [ffff888078fdf820, ffff888078fdf828) The buggy address belongs to the page: page:ffffea0001e3f7c0 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x78fdf flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000000200 ffffea00051fcd40 0000001600000016 ffff888016c41280 raw: 0000000000000000 0000000080660066 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 0x112cc0(GFP_USER|__GFP_NOWARN|__GFP_NORETRY), pid 6585, ts 147259307457, free_ts 147254814999 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] slab_alloc mm/slub.c:3233 [inline] __kmalloc+0x11d/0x340 mm/slub.c:4408 kmalloc include/linux/slab.h:612 [inline] kernfs_fop_write_iter+0x14f/0x500 fs/kernfs/file.c:273 call_write_iter include/linux/fs.h:2179 [inline] new_sync_write fs/read_write.c:507 [inline] vfs_write+0x748/0xd70 fs/read_write.c:594 ksys_write+0x153/0x260 fs/read_write.c:647 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 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1340 [inline] free_pcp_prepare mm/page_alloc.c:1391 [inline] free_unref_page_prepare+0x637/0x6c0 mm/page_alloc.c:3317 free_unref_page+0x8f/0x2a0 mm/page_alloc.c:3396 free_slab mm/slub.c:2020 [inline] discard_slab mm/slub.c:2026 [inline] __unfreeze_partials+0x188/0x1e0 mm/slub.c:2512 put_cpu_partial+0x12d/0x190 mm/slub.c:2592 qlist_free_all+0x35/0x90 mm/kasan/quarantine.c:176 kasan_quarantine_reduce+0x150/0x160 mm/kasan/quarantine.c:283 __kasan_slab_alloc+0x2f/0xc0 mm/kasan/common.c:444 kasan_slab_alloc include/linux/kasan.h:254 [inline] slab_post_alloc_hook+0x4c/0x380 mm/slab.h:519 slab_alloc_node mm/slub.c:3225 [inline] slab_alloc mm/slub.c:3233 [inline] kmem_cache_alloc+0x15d/0x280 mm/slub.c:3238 getname_flags+0xb7/0x4f0 fs/namei.c:138 do_sys_openat2+0xdd/0x500 fs/open.c:1249 do_sys_open fs/open.c:1271 [inline] __do_sys_openat fs/open.c:1287 [inline] __se_sys_openat fs/open.c:1282 [inline] __x64_sys_openat+0x135/0x160 fs/open.c:1282 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 Memory state around the buggy address: ffff888078fdf700: fc fb fc fc fc fc fb fc fc fc fc fb fc fc fc fc ffff888078fdf780: fb fc fc fc fc fb fc fc fc fc fb fc fc fc fc fb >ffff888078fdf800: fc fc fc fc 01 fc fc fc fc 00 fc fc fc fc 00 fc ^ ffff888078fdf880: fc fc fc fa fc fc fc fc fa fc fc fc fc fa fc fc ffff888078fdf900: fc fc fa fc fc fc fc fa fc fc fc fc fa fc fc fc ==================================================================