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BUG: KASAN: slab-out-of-bounds in vsscanf+0x2666/0x2ef0 lib/vsprintf.c:3287
Read of size 1 at addr ffff88808da48bc5 by task syz-executor.0/11227

CPU: 0 PID: 11227 Comm: syz-executor.0 Not tainted 5.7.0-rc5-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 11227:
 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 10855:
 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_task_free+0xa3/0xc0 security/security.c:1571
 __put_task_struct+0xbe/0x280 kernel/fork.c:748
 rcu_do_batch kernel/rcu/tree.c:2206 [inline]
 rcu_core+0x816/0x1120 kernel/rcu/tree.c:2433
 __do_softirq+0x268/0x80c kernel/softirq.c:292

The buggy address belongs to the object at ffff88808da48bc0
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 5 bytes inside of
 32-byte region [ffff88808da48bc0, ffff88808da48be0)
The buggy address belongs to the page:
page:ffffea0002369200 refcount:1 mapcount:0 mapping:00000000056108a2 index:0xffff88808da48fc1
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea0002531a88 ffffea00027ce248 ffff8880aa4001c0
raw: ffff88808da48fc1 ffff88808da48000 000000010000003f 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88808da48a80: fb fb fb fb fc fc fc fc 00 00 fc fc fc fc fc fc
 ffff88808da48b00: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
>ffff88808da48b80: fb fb fb fb fc fc fc fc 05 fc fc fc fc fc fc fc
                                           ^
 ffff88808da48c00: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff88808da48c80: fb fb fb fb fc fc fc fc 00 00 01 fc fc fc fc fc
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