bisecting fixing commit since a1b977b49b66c75e6c51a515f6700371ae720217
building syzkaller on fc7735a27949755327024847e12dcc1b868bcb99
testing commit a1b977b49b66c75e6c51a515f6700371ae720217 with gcc (GCC) 8.4.1 20210217
kernel signature: bf5d022b3c3766934fde03f99ec55565e6f94fccd31c0637411678771f8d8682
all runs: crashed: KASAN: use-after-free Read in ntfs_iget
testing current HEAD 255b58a2b3af0baa0ee11507390349217b8b73b0
testing commit 255b58a2b3af0baa0ee11507390349217b8b73b0 with gcc (GCC) 8.4.1 20210217
kernel signature: 7ead67d00d4fb6721451bfea289d1bcc6f009a8ce5a6d517003c00ce929f4840
all runs: crashed: KASAN: use-after-free Read in ntfs_iget
revisions tested: 2, total time: 23m10.181684849s (build: 15m45.767977844s, test: 6m30.440609534s)
the crash still happens on HEAD
commit msg: Linux 4.19.176
crash: KASAN: use-after-free Read in ntfs_iget
ntfs: (device loop3): load_and_init_upcase(): Failed to load $UpCase from the volume. Using default.
ntfs: (device loop3): ntfs_is_extended_system_file(): Inode hard link count doesn't match number of name attributes. You should run chkdsk.
==================================================================
BUG: KASAN: use-after-free in ntfs_read_locked_inode+0x413c/0x5200 fs/ntfs/inode.c:670
Read of size 8 at addr ffff8881c989a6cd by task syz-executor.0/7453

CPU: 1 PID: 7453 Comm: syz-executor.0 Not tainted 4.19.176-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+0x17c/0x226 lib/dump_stack.c:118
 print_address_description.cold.6+0x9/0x211 mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report mm/kasan/report.c:412 [inline]
 kasan_report.cold.7+0x242/0x2fe mm/kasan/report.c:396
 __asan_report_load_n_noabort+0xf/0x20 mm/kasan/report.c:443
 ntfs_read_locked_inode+0x413c/0x5200 fs/ntfs/inode.c:670
 ntfs_iget+0xe6/0x120 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+0x1ece/0x79c0 fs/ntfs/super.c:2908
 mount_bdev+0x26f/0x330 fs/super.c:1158
 ntfs_mount+0x10/0x20 fs/ntfs/super.c:3065
 mount_fs+0x7f/0x2b0 fs/super.c:1261
 vfs_kern_mount.part.11+0x58/0x3d0 fs/namespace.c:961
 vfs_kern_mount fs/namespace.c:951 [inline]
 do_new_mount fs/namespace.c:2469 [inline]
 do_mount+0x376/0x2710 fs/namespace.c:2799
 ksys_mount+0xb1/0xd0 fs/namespace.c:3015
 __do_sys_mount fs/namespace.c:3029 [inline]
 __se_sys_mount fs/namespace.c:3026 [inline]
 __x64_sys_mount+0xb9/0x150 fs/namespace.c:3026
 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x466d6a
Code: 48 c7 c2 bc ff ff ff f7 d8 64 89 02 b8 ff ff ff ff eb d2 e8 b8 04 00 00 0f 1f 84 00 00 00 00 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f6296c81fa8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000020000200 RCX: 0000000000466d6a
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007f6296c82000
RBP: 00007f6296c82040 R08: 00007f6296c82040 R09: 0000000020000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000020000000
R13: 0000000020000100 R14: 00007f6296c82000 R15: 000000002007dd00

The buggy address belongs to the page:
page:ffffea0007262680 count:0 mapcount:0 mapping:0000000000000000 index:0x1
flags: 0x17ffe0000000000()
raw: 017ffe0000000000 ffffea00072626c8 ffffea0007262648 0000000000000000
raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8881c989a580: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8881c989a600: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff8881c989a680: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                              ^
 ffff8881c989a700: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8881c989a780: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================