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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 ffff8880172fec38 by task syz-executor.5/28938

CPU: 1 PID: 28938 Comm: syz-executor.5 Not tainted 5.10.0-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+0x107/0x163 lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xae/0x4c8 mm/kasan/report.c:385
 __kasan_report mm/kasan/report.c:545 [inline]
 kasan_report.cold+0x1f/0x37 mm/kasan/report.c:562
 squashfs_get_id+0x1ae/0x1d0 fs/squashfs/id.c:38
 squashfs_new_inode fs/squashfs/inode.c:55 [inline]
 squashfs_read_inode+0x1ee/0x1b40 fs/squashfs/inode.c:120
 squashfs_fill_super+0x1140/0x23b0 fs/squashfs/super.c:310
 get_tree_bdev+0x421/0x740 fs/super.c:1344
 vfs_get_tree+0x89/0x2f0 fs/super.c:1549
 do_new_mount fs/namespace.c:2875 [inline]
 path_mount+0x13ad/0x20c0 fs/namespace.c:3205
 do_mount fs/namespace.c:3218 [inline]
 __do_sys_mount fs/namespace.c:3426 [inline]
 __se_sys_mount fs/namespace.c:3403 [inline]
 __x64_sys_mount+0x27f/0x300 fs/namespace.c:3403
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x46090a
Code: b8 a6 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 ad 89 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 8a 89 fb ff c3 66 0f 1f 84 00 00 00 00 00
RSP: 002b:00007f88cd76ba88 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f88cd76bb20 RCX: 000000000046090a
RDX: 0000000020000000 RSI: 00000000200000c0 RDI: 00007f88cd76bae0
RBP: 00007f88cd76bae0 R08: 00007f88cd76bb20 R09: 0000000020000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000020000000
R13: 00000000200000c0 R14: 0000000020000200 R15: 0000000020010200

Allocated by task 8491:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48
 kasan_set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc.constprop.0+0xc2/0xd0 mm/kasan/common.c:461
 slab_post_alloc_hook mm/slab.h:526 [inline]
 slab_alloc_node mm/slub.c:2891 [inline]
 slab_alloc mm/slub.c:2899 [inline]
 __kmalloc_track_caller+0x1dc/0x3d0 mm/slub.c:4464
 kstrdup+0x36/0x70 mm/util.c:60
 kstrdup_const+0x53/0x80 mm/util.c:83
 alloc_vfsmnt+0xb5/0x680 fs/namespace.c:186
 clone_mnt+0x6c/0xfa0 fs/namespace.c:1039
 copy_tree+0x3ad/0xae0 fs/namespace.c:1850
 copy_mnt_ns+0x143/0xa60 fs/namespace.c:3315
 create_new_namespaces+0xd6/0xb10 kernel/nsproxy.c:78
 unshare_nsproxy_namespaces+0xbd/0x1f0 kernel/nsproxy.c:231
 ksys_unshare+0x445/0x8e0 kernel/fork.c:2949
 __do_sys_unshare kernel/fork.c:3017 [inline]
 __se_sys_unshare kernel/fork.c:3015 [inline]
 __x64_sys_unshare+0x2d/0x40 kernel/fork.c:3015
 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 ffff8880172fec30
 which belongs to the cache kmalloc-8 of size 8
The buggy address is located 0 bytes to the right of
 8-byte region [ffff8880172fec30, ffff8880172fec38)
The buggy address belongs to the page:
page:00000000d9e8d2b7 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x172fe
flags: 0xfff00000000200(slab)
raw: 00fff00000000200 dead000000000100 dead000000000122 ffff888010041c80
raw: 0000000000000000 0000000080660066 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880172feb00: fc fc fc 00 fc fc fc fc 00 fc fc fc fc 00 fc fc
 ffff8880172feb80: fc fc fa fc fc fc fc fb fc fc fc fc 00 fc fc fc
>ffff8880172fec00: fc 00 fc fc fc fc 00 fc fc fc fc 00 fc fc fc fc
                                        ^
 ffff8880172fec80: fa fc fc fc fc 00 fc fc fc fc 00 fc fc fc fc 00
 ffff8880172fed00: fc fc fc fc 00 fc fc fc fc 00 fc fc fc fc 00 fc
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