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BUG: KASAN: slab-out-of-bounds in vsscanf+0x2666/0x2ef0 lib/vsprintf.c:3321
Read of size 1 at addr ffff888097990d18 by task syz-executor.0/6164

CPU: 1 PID: 6164 Comm: syz-executor.0 Not tainted 5.8.0-rc2-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+0x1f0/0x31e lib/dump_stack.c:118
 print_address_description+0x66/0x5a0 mm/kasan/report.c:383
 __kasan_report mm/kasan/report.c:513 [inline]
 kasan_report+0x132/0x1d0 mm/kasan/report.c:530
 vsscanf+0x2666/0x2ef0 lib/vsprintf.c:3321
 sscanf+0x6c/0x90 lib/vsprintf.c:3527
 smk_set_cipso+0x374/0x6c0 security/smack/smackfs.c:908
 __vfs_write+0x9c/0x6e0 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+0x73/0xe0 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45cb19
Code: Bad RIP value.
RSP: 002b:00007f0bb8b81c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000000000050e840 RCX: 000000000045cb19
RDX: 0000000000000017 RSI: 0000000020000140 RDI: 0000000000000003
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000d49 R14: 00000000004cfa53 R15: 00007f0bb8b826d4

Allocated by task 6164:
 save_stack mm/kasan/common.c:48 [inline]
 set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc+0x103/0x140 mm/kasan/common.c:494
 __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/0x6c0 security/smack/smackfs.c:859
 __vfs_write+0x9c/0x6e0 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+0x73/0xe0 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 3883:
 save_stack mm/kasan/common.c:48 [inline]
 set_track mm/kasan/common.c:56 [inline]
 kasan_set_free_info mm/kasan/common.c:316 [inline]
 __kasan_slab_free+0x114/0x170 mm/kasan/common.c:455
 __cache_free mm/slab.c:3426 [inline]
 kfree+0x10a/0x220 mm/slab.c:3757
 tomoyo_path_perm+0x59b/0x740 security/tomoyo/file.c:842
 security_inode_getattr+0xc0/0x140 security/security.c:1278
 vfs_getattr fs/stat.c:121 [inline]
 vfs_statx+0x118/0x380 fs/stat.c:206
 vfs_lstat include/linux/fs.h:3301 [inline]
 __do_sys_newlstat fs/stat.c:374 [inline]
 __se_sys_newlstat fs/stat.c:368 [inline]
 __x64_sys_newlstat+0x81/0xd0 fs/stat.c:368
 do_syscall_64+0x73/0xe0 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff888097990d00
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 24 bytes inside of
 32-byte region [ffff888097990d00, ffff888097990d20)
The buggy address belongs to the page:
page:ffffea00025e6400 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888097990fc1
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea00023ff508 ffffea000277c308 ffff8880aa4001c0
raw: ffff888097990fc1 ffff888097990000 0000000100000039 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888097990c00: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff888097990c80: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
>ffff888097990d00: 00 00 00 fc fc fc fc fc fb fb fb fb fc fc fc fc
                            ^
 ffff888097990d80: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff888097990e00: 00 00 01 fc fc fc fc fc fb fb fb fb fc fc fc fc
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