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BUG: KASAN: slab-out-of-bounds in squashfs_get_id+0x1ae/0x1d0 fs/squashfs/id.c:38
Read of size 8 at addr ffff88809796ced8 by task syz-executor.2/3697

CPU: 1 PID: 3697 Comm: syz-executor.2 Not tainted 5.9.0-rc6-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+0x198/0x1fd lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xae/0x497 mm/kasan/report.c:383
 __kasan_report mm/kasan/report.c:513 [inline]
 kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530
 squashfs_get_id+0x1ae/0x1d0 fs/squashfs/id.c:38
 squashfs_new_inode fs/squashfs/inode.c:51 [inline]
 squashfs_read_inode+0x197/0x1940 fs/squashfs/inode.c:120
 squashfs_fill_super+0x1079/0x1ecf fs/squashfs/super.c:310
 get_tree_bdev+0x421/0x740 fs/super.c:1342
 vfs_get_tree+0x89/0x2f0 fs/super.c:1547
 do_new_mount fs/namespace.c:2875 [inline]
 path_mount+0x1387/0x20a0 fs/namespace.c:3192
 do_mount fs/namespace.c:3205 [inline]
 __do_sys_mount fs/namespace.c:3413 [inline]
 __se_sys_mount fs/namespace.c:3390 [inline]
 __x64_sys_mount+0x27f/0x300 fs/namespace.c:3390
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x460bca
Code: b8 a6 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 dd 87 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 ba 87 fb ff c3 66 0f 1f 84 00 00 00 00 00
RSP: 002b:00007f0a8ac30a88 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f0a8ac30b20 RCX: 0000000000460bca
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007f0a8ac30ae0
RBP: 00007f0a8ac30ae0 R08: 00007f0a8ac30b20 R09: 0000000020000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000020000000
R13: 0000000020000100 R14: 0000000020000200 R15: 0000000020000740

Allocated by task 1:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48
 kasan_set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:461
 __do_kmalloc mm/slab.c:3655 [inline]
 __kmalloc_track_caller+0x1ae/0x360 mm/slab.c:3670
 kstrdup+0x36/0x70 mm/util.c:60
 kstrdup_const+0x53/0x80 mm/util.c:82
 __kernfs_new_node+0x9d/0x8b0 fs/kernfs/dir.c:623
 kernfs_new_node+0x93/0x120 fs/kernfs/dir.c:689
 __kernfs_create_file+0x51/0x350 fs/kernfs/file.c:1002
 cgroup_add_file kernel/cgroup/cgroup.c:3821 [inline]
 cgroup_addrm_files+0x3d6/0x9c0 kernel/cgroup/cgroup.c:3881
 css_populate_dir+0x2f6/0x450 kernel/cgroup/cgroup.c:1684
 cgroup_mkdir+0x886/0x1190 kernel/cgroup/cgroup.c:5354
 kernfs_iop_mkdir+0x146/0x1d0 fs/kernfs/dir.c:1127
 vfs_mkdir+0x507/0x770 fs/namei.c:3649
 do_mkdirat+0x262/0x2d0 fs/namei.c:3672
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff88809796cec0
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 24 bytes inside of
 32-byte region [ffff88809796cec0, ffff88809796cee0)
The buggy address belongs to the page:
page:0000000018936bf9 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88809796cfc1 pfn:0x9796c
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea0002a4b888 ffffea0002870288 ffff8880aa040100
raw: ffff88809796cfc1 ffff88809796c000 000000010000002f 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88809796cd80: fa fb fb fb fc fc fc fc 00 00 01 fc fc fc fc fc
 ffff88809796ce00: fa fb fb fb fc fc fc fc 00 fc fc fc fc fc fc fc
>ffff88809796ce80: 00 00 06 fc fc fc fc fc 00 05 fc fc fc fc fc fc
                                                    ^
 ffff88809796cf00: fb fb fb fb fc fc fc fc 00 00 fc fc fc fc fc fc
 ffff88809796cf80: 00 00 01 fc fc fc fc fc fc fc fc fc fc fc fc fc
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