audit: type=1804 audit(1605782270.383:25): pid=10849 uid=0 auid=0 ses=4 subj==unconfined op=invalid_pcr cause=ToMToU comm="syz-executor.2" name="/root/syzkaller-testdir955926456/syzkaller.tSoBsR/30/file0/file0/bus" dev="ramfs" ino=35922 res=1
EXT4-fs (loop2): orphan cleanup on readonly fs
==================================================================
EXT4-fs error (device loop2): ext4_quota_enable:5841: comm syz-executor.2: Bad quota inode # 3
BUG: KASAN: slab-out-of-bounds in squashfs_get_id+0x1ae/0x1d0 fs/squashfs/id.c:51
Read of size 8 at addr ffff8880a9aa07f0 by task syz-executor.1/10832

CPU: 1 PID: 10832 Comm: syz-executor.1 Not tainted 4.19.158-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+0x1fc/0x2fe lib/dump_stack.c:118
 print_address_description.cold+0x54/0x219 mm/kasan/report.c:256
 kasan_report_error.cold+0x8a/0x1c7 mm/kasan/report.c:354
 kasan_report mm/kasan/report.c:412 [inline]
 __asan_report_load8_noabort+0x88/0x90 mm/kasan/report.c:433
 squashfs_get_id+0x1ae/0x1d0 fs/squashfs/id.c:51
 squashfs_new_inode fs/squashfs/inode.c:64 [inline]
 squashfs_read_inode+0x1b4/0x1b40 fs/squashfs/inode.c:133
 squashfs_fill_super+0x1655/0x1c00 fs/squashfs/super.c:318
EXT4-fs warning (device loop2): ext4_enable_quotas:5878: Failed to enable quota tracking (type=0, err=-116). Please run e2fsck to fix.
 mount_bdev+0x2fc/0x3b0 fs/super.c:1158
audit: type=1804 audit(1605782270.383:26): pid=10835 uid=0 auid=0 ses=4 subj==unconfined op=invalid_pcr cause=ToMToU comm="syz-executor.2" name="/root/syzkaller-testdir955926456/syzkaller.tSoBsR/30/file0/file0/bus" dev="ramfs" ino=35922 res=1
audit: type=1804 audit(1605782271.003:27): pid=10871 uid=0 auid=0 ses=4 subj==unconfined op=invalid_pcr cause=ToMToU comm="syz-executor.0" name="/root/syzkaller-testdir227643330/syzkaller.gHjvQB/27/bus" dev="sda1" ino=15761 res=1
 mount_fs+0xa3/0x30c fs/super.c:1261
 vfs_kern_mount.part.0+0x68/0x470 fs/namespace.c:961
 vfs_kern_mount fs/namespace.c:951 [inline]
 do_new_mount fs/namespace.c:2469 [inline]
 do_mount+0x113c/0x2f10 fs/namespace.c:2799
 ksys_mount+0xcf/0x130 fs/namespace.c:3015
 __do_sys_mount fs/namespace.c:3029 [inline]
 __se_sys_mount fs/namespace.c:3026 [inline]
 __x64_sys_mount+0xba/0x150 fs/namespace.c:3026
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
EXT4-fs (loop2): Cannot turn on quotas: error -116
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:00007fd9e9163a88 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fd9e9163b20 RCX: 000000000046090a
RDX: 0000000020000040 RSI: 0000000020000100 RDI: 00007fd9e9163ae0
RBP: 00007fd9e9163ae0 R08: 00007fd9e9163b20 R09: 0000000020000040
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000020000040
R13: 0000000020000100 R14: 0000000020000200 R15: 0000000020000300

Allocated by task 10006:
 kmem_cache_alloc_trace+0x12f/0x380 mm/slab.c:3625
 kmalloc include/linux/slab.h:515 [inline]
 do_signalfd4+0x272/0x3d0 fs/signalfd.c:277
 __do_sys_signalfd4 fs/signalfd.c:320 [inline]
 __se_sys_signalfd4 fs/signalfd.c:311 [inline]
 __x64_sys_signalfd4+0x138/0x1c0 fs/signalfd.c:311
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 10006:
 __cache_free mm/slab.c:3503 [inline]
 kfree+0xcc/0x210 mm/slab.c:3822
 signalfd_release+0x33/0x40 fs/signalfd.c:57
 __fput+0x2ce/0x890 fs/file_table.c:278
 task_work_run+0x148/0x1c0 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0xbed/0x2be0 kernel/exit.c:890
 do_group_exit+0x125/0x310 kernel/exit.c:993
 __do_sys_exit_group kernel/exit.c:1004 [inline]
 __se_sys_exit_group kernel/exit.c:1002 [inline]
 __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:1002
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8880a9aa07c0
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 16 bytes to the right of
 32-byte region [ffff8880a9aa07c0, ffff8880a9aa07e0)
The buggy address belongs to the page:
page:ffffea0002a6a800 count:1 mapcount:0 mapping:ffff88813bff01c0 index:0xffff8880a9aa0fc1
flags: 0xfff00000000100(slab)
raw: 00fff00000000100 ffffea0002aea648 ffffea0002a58208 ffff88813bff01c0
raw: ffff8880a9aa0fc1 ffff8880a9aa0000 000000010000002d 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a9aa0680: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8880a9aa0700: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
>ffff8880a9aa0780: 00 fc fc fc fc fc fc fc fb fb fb fb fc fc fc fc
                                                             ^
 ffff8880a9aa0800: 00 04 fc fc fc fc fc fc 00 04 fc fc fc fc fc fc
 ffff8880a9aa0880: 00 04 fc fc fc fc fc fc 00 04 fc fc fc fc fc fc
==================================================================