==================================================================
BUG: KASAN: slab-out-of-bounds in squashfs_get_id+0x181/0x1a0 fs/squashfs/id.c:51
Read of size 8 at addr ffff8880b50f0c78 by task syz-executor848/7975

CPU: 1 PID: 7975 Comm: syz-executor848 Not tainted 4.14.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x1b2/0x283 lib/dump_stack.c:58
 print_address_description.cold+0x54/0x1d3 mm/kasan/report.c:252
 kasan_report_error.cold+0x8a/0x194 mm/kasan/report.c:351
 kasan_report mm/kasan/report.c:409 [inline]
 __asan_report_load8_noabort+0x68/0x70 mm/kasan/report.c:430
 squashfs_get_id+0x181/0x1a0 fs/squashfs/id.c:51
 squashfs_new_inode fs/squashfs/inode.c:68 [inline]
 squashfs_read_inode+0x1b6/0x19e0 fs/squashfs/inode.c:133
 squashfs_fill_super+0x1501/0x1aa0 fs/squashfs/super.c:318
 mount_bdev+0x2b3/0x360 fs/super.c:1134
 mount_fs+0x92/0x2a0 fs/super.c:1237
 vfs_kern_mount.part.0+0x5b/0x470 fs/namespace.c:1046
 vfs_kern_mount fs/namespace.c:1036 [inline]
 do_new_mount fs/namespace.c:2549 [inline]
 do_mount+0xe53/0x2a00 fs/namespace.c:2879
 SYSC_mount fs/namespace.c:3095 [inline]
 SyS_mount+0xa8/0x120 fs/namespace.c:3072
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x446d2a
RSP: 002b:00007ffd1c766eb8 EFLAGS: 00000293 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffd1c766f10 RCX: 0000000000446d2a
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007ffd1c766ed0
RBP: 00007ffd1c766ed0 R08: 00007ffd1c766f10 R09: 00007ffd00000015
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000005
R13: 0000000000000004 R14: 0000000000000003 R15: 0000000000000003

Allocated by task 328:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc+0xeb/0x160 mm/kasan/kasan.c:551
 kmem_cache_alloc_trace+0x131/0x3d0 mm/slab.c:3618
 kmalloc include/linux/slab.h:488 [inline]
 kzalloc include/linux/slab.h:661 [inline]
 aa_alloc_task_context+0x4d/0x90 security/apparmor/context.c:40
 apparmor_cred_prepare+0x1a/0xb0 security/apparmor/lsm.c:84
 security_prepare_creds+0x76/0xb0 security/security.c:1008
 prepare_creds+0x2ef/0x490 kernel/cred.c:282
 prepare_exec_creds+0xd/0xf0 kernel/cred.c:301
 prepare_bprm_creds fs/exec.c:1407 [inline]
 do_execveat_common+0x32b/0x1f30 fs/exec.c:1748
 do_execve+0x33/0x50 fs/exec.c:1860
 call_usermodehelper_exec_async+0x2ed/0x510 kernel/umh.c:109
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404

Freed by task 418:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0xc3/0x1a0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3496 [inline]
 kfree+0xc9/0x250 mm/slab.c:3815
 aa_free_task_context+0xda/0x130 security/apparmor/context.c:54
 apparmor_cred_free+0x34/0x70 security/apparmor/lsm.c:58
 security_cred_free+0x71/0xb0 security/security.c:1003
 put_cred_rcu+0xe3/0x300 kernel/cred.c:117
 __rcu_reclaim kernel/rcu/rcu.h:195 [inline]
 rcu_do_batch kernel/rcu/tree.c:2699 [inline]
 invoke_rcu_callbacks kernel/rcu/tree.c:2962 [inline]
 __rcu_process_callbacks kernel/rcu/tree.c:2929 [inline]
 rcu_process_callbacks+0x780/0x1180 kernel/rcu/tree.c:2946
 __do_softirq+0x254/0xa1d kernel/softirq.c:288

The buggy address belongs to the object at ffff8880b50f0c40
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 24 bytes to the right of
 32-byte region [ffff8880b50f0c40, ffff8880b50f0c60)
The buggy address belongs to the page:
page:ffffea0002d43c00 count:1 mapcount:0 mapping:ffff8880b50f0000 index:0xffff8880b50f0fc1
flags: 0xfff00000000100(slab)
raw: 00fff00000000100 ffff8880b50f0000 ffff8880b50f0fc1 000000010000003f
raw: ffffea0002c3a7e0 ffff88813fe81248 ffff88813fe801c0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880b50f0b00: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8880b50f0b80: 00 fc fc fc fc fc fc fc fb fb fb fb fc fc fc fc
>ffff8880b50f0c00: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
                                                                ^
 ffff8880b50f0c80: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8880b50f0d00: 00 fc fc fc fc fc fc fc fb fb fb fb fc fc fc fc
==================================================================