bisecting fixing commit since cbfa1702aaf69b2311ea1b35e04f113c48368c67
building syzkaller on 9602ddf403bdf3cfd87efef14becc76f9a38b81d
testing commit cbfa1702aaf69b2311ea1b35e04f113c48368c67 with gcc (GCC) 8.4.1 20210217
kernel signature: 0b9c3b989f246d689b7caee3ed49c53a7c5289a797b1929930fa912f542f933b
all runs: crashed: KASAN: use-after-free Read in ntfs_iget
testing current HEAD 29c52025152bab4c557d8174da58f1a4c8e70438
testing commit 29c52025152bab4c557d8174da58f1a4c8e70438 with gcc (GCC) 8.4.1 20210217
kernel signature: 0e4f8b2617e326297f639f93476a41607563b776bb46175cf38228b4c5f6704f
all runs: crashed: KASAN: use-after-free Read in ntfs_iget
revisions tested: 2, total time: 21m15.147883066s (build: 14m53.933228442s, test: 5m27.904127507s)
the crash still happens on HEAD
commit msg: Linux 4.14.221
crash: KASAN: use-after-free Read in ntfs_iget
ntfs: (device loop0): load_and_init_upcase(): Failed to load $UpCase from the volume. Using default.
IPv6: ADDRCONF(NETDEV_UP): batadv_slave_1: link is not ready
==================================================================
batman_adv: batadv0: Interface activated: batadv_slave_1
BUG: KASAN: use-after-free in ntfs_read_locked_inode+0x41ad/0x51f0 fs/ntfs/inode.c:677
Read of size 8 at addr ffff8881c9fed6cd by task syz-executor.0/7189

CPU: 1 PID: 7189 Comm: syz-executor.0 Not tainted 4.14.221-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+0x14b/0x1e7 lib/dump_stack.c:58
 print_address_description.cold.6+0x9/0x1ca mm/kasan/report.c:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report mm/kasan/report.c:409 [inline]
 kasan_report.cold.7+0x11a/0x2d3 mm/kasan/report.c:393
batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3d) already exists on: batadv_slave_0
 __asan_report_load_n_noabort+0xf/0x20 mm/kasan/report.c:440
batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems!
 ntfs_read_locked_inode+0x41ad/0x51f0 fs/ntfs/inode.c:677
 ntfs_iget+0xda/0x110 fs/ntfs/inode.c:190
 load_and_init_attrdef fs/ntfs/super.c:1603 [inline]
 load_system_files fs/ntfs/super.c:1831 [inline]
 ntfs_fill_super+0x1eb6/0x76c0 fs/ntfs/super.c:2908
batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3d) already exists on: batadv_slave_0
 mount_bdev+0x26f/0x330 fs/super.c:1134
batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems!
 ntfs_mount+0x10/0x20 fs/ntfs/super.c:3065
 mount_fs+0x7f/0x270 fs/super.c:1237
 vfs_kern_mount.part.9+0x58/0x3c0 fs/namespace.c:1046
 vfs_kern_mount fs/namespace.c:1036 [inline]
 do_new_mount fs/namespace.c:2549 [inline]
 do_mount+0x352/0x2af0 fs/namespace.c:2879
batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3d) already exists on: batadv_slave_0
 SYSC_mount fs/namespace.c:3095 [inline]
 SyS_mount+0xb1/0xd0 fs/namespace.c:3072
 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292
batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems!
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x466baa
RSP: 002b:00007fb47acdafa8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000020000200 RCX: 0000000000466baa
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007fb47acdb000
RBP: 00007fb47acdb040 R08: 00007fb47acdb040 R09: 0000000020000000
batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3d) already exists on: batadv_slave_0
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000020000000
R13: 0000000020000100 R14: 00007fb47acdb000 R15: 000000002007dd00

The buggy address belongs to the page:
page:ffffea000727fb40 count:0 mapcount:0 mapping:          (null) index:0x1
flags: 0x17ffe0000000000()
raw: 017ffe0000000000 0000000000000000 0000000000000001 00000000ffffffff
raw: dead000000000100 dead000000000200 0000000000000000 0000000000000000
page dumped because: kasan: bad access detected

batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems!
Memory state around the buggy address:
 ffff8881c9fed580: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8881c9fed600: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff8881c9fed680: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                              ^
 ffff8881c9fed700: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8881c9fed780: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================