F2FS-fs (loop0): Magic Mismatch, valid(0xf2f52010) - read(0x0)
F2FS-fs (loop0): Can't find valid F2FS filesystem in 1th superblock
F2FS-fs (loop0): invalid crc value
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BUG: KASAN: use-after-free in build_sit_entries fs/f2fs/segment.c:3653 [inline]
BUG: KASAN: use-after-free in build_segment_manager+0xb92d/0xbf70 fs/f2fs/segment.c:3852
Read of size 4 at addr ffff8801acc556c0 by task syzkaller118486/4540

CPU: 1 PID: 4540 Comm: syzkaller118486 Not tainted 4.17.0-rc1+ #9
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+0x1b9/0x294 lib/dump_stack.c:113
 print_address_description+0x6c/0x20b mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report.cold.7+0x242/0x2fe mm/kasan/report.c:412
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:432
 build_sit_entries fs/f2fs/segment.c:3653 [inline]
 build_segment_manager+0xb92d/0xbf70 fs/f2fs/segment.c:3852
 f2fs_fill_super+0x4095/0x7bf0 fs/f2fs/super.c:2803
 mount_bdev+0x30c/0x3e0 fs/super.c:1165
 f2fs_mount+0x34/0x40 fs/f2fs/super.c:3020
 mount_fs+0xae/0x328 fs/super.c:1268
 vfs_kern_mount.part.34+0xd4/0x4d0 fs/namespace.c:1037
 vfs_kern_mount fs/namespace.c:1027 [inline]
 do_new_mount fs/namespace.c:2517 [inline]
 do_mount+0x564/0x3070 fs/namespace.c:2847
 ksys_mount+0x12d/0x140 fs/namespace.c:3063
 __do_sys_mount fs/namespace.c:3077 [inline]
 __se_sys_mount fs/namespace.c:3074 [inline]
 __x64_sys_mount+0xbe/0x150 fs/namespace.c:3074
 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x443c9a
RSP: 002b:00007ffd1f003538 EFLAGS: 00000297 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000020000b70 RCX: 0000000000443c9a
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007ffd1f003540
RBP: 0000000000000003 R08: 0000000020016600 R09: 000000000000000a
R10: 0000000000000000 R11: 0000000000000297 R12: 0000000000000004
R13: 0000000000402b90 R14: 0000000000000000 R15: 0000000000000000

The buggy address belongs to the page:
page:ffffea0006b31540 count:0 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0x2fffc0000000000()
raw: 02fffc0000000000 0000000000000000 0000000000000000 00000000ffffffff
raw: 0000000000000000 ffffea0006b30101 0000000000000000 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801acc55580: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8801acc55600: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff8801acc55680: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                           ^
 ffff8801acc55700: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8801acc55780: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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