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BUG: KASAN: slab-out-of-bounds in vsscanf+0x2666/0x2ef0 lib/vsprintf.c:3294
Read of size 1 at addr ffff88809dd467c2 by task syz-executor.5/22706

CPU: 1 PID: 22706 Comm: syz-executor.5 Not tainted 5.7.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1e9/0x30e lib/dump_stack.c:118
 print_address_description+0x74/0x5c0 mm/kasan/report.c:382
 __kasan_report+0x103/0x1a0 mm/kasan/report.c:511
 kasan_report+0x4d/0x80 mm/kasan/common.c:625

Allocated by task 22706:
 save_stack mm/kasan/common.c:49 [inline]
 set_track mm/kasan/common.c:57 [inline]
 __kasan_kmalloc+0x114/0x160 mm/kasan/common.c:495
 __do_kmalloc mm/slab.c:3656 [inline]
 __kmalloc_track_caller+0x249/0x320 mm/slab.c:3671
 memdup_user_nul+0x26/0xf0 mm/util.c:259
 smk_set_cipso+0xff/0x6a0 security/smack/smackfs.c:859
 __vfs_write+0xa7/0x710 fs/read_write.c:495
 vfs_write+0x274/0x580 fs/read_write.c:559
 ksys_write+0x11b/0x220 fs/read_write.c:612
 do_syscall_64+0xf3/0x1b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x49/0xb3

Freed by task 7142:
 save_stack mm/kasan/common.c:49 [inline]
 set_track mm/kasan/common.c:57 [inline]
 kasan_set_free_info mm/kasan/common.c:317 [inline]
 __kasan_slab_free+0x125/0x190 mm/kasan/common.c:456
 __cache_free mm/slab.c:3426 [inline]
 kfree+0x10a/0x220 mm/slab.c:3757
 security_sk_free+0x4d/0x90 security/security.c:2137
 sk_prot_free net/core/sock.c:1637 [inline]
 __sk_destruct+0x5f9/0x740 net/core/sock.c:1725
 inet_release+0x135/0x180 net/ipv4/af_inet.c:427
 __sock_release net/socket.c:605 [inline]
 sock_close+0xd8/0x260 net/socket.c:1283
 __fput+0x2ed/0x750 fs/file_table.c:280
 task_work_run+0x147/0x1d0 kernel/task_work.c:123
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop arch/x86/entry/common.c:165 [inline]
 prepare_exit_to_usermode+0x48e/0x600 arch/x86/entry/common.c:196
 entry_SYSCALL_64_after_hwframe+0x49/0xb3

The buggy address belongs to the object at ffff88809dd467c0
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 2 bytes inside of
 32-byte region [ffff88809dd467c0, ffff88809dd467e0)
The buggy address belongs to the page:
page:ffffea0002775180 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88809dd46fc1
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea00027bb308 ffffea0002799988 ffff8880aa4001c0
raw: ffff88809dd46fc1 ffff88809dd46000 0000000100000037 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88809dd46680: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff88809dd46700: fb fb fb fb fc fc fc fc 00 00 00 fc fc fc fc fc
>ffff88809dd46780: fb fb fb fb fc fc fc fc 02 fc fc fc fc fc fc fc
                                           ^
 ffff88809dd46800: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff88809dd46880: fb fb fb fb fc fc fc fc 00 00 01 fc fc fc fc fc
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