KASAN: slab-out-of-bounds Read in f2fs_build_segment_manager

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: a1b977b4 Linux 4.19.150
git tree: linux-4.19.y
console output: https://syzkaller.appspot.com/x/log.txt?x=14ee35d7900000
kernel config: https://syzkaller.appspot.com/x/.config?x=c14008c8da1ca4d4
dashboard link: https://syzkaller.appspot.com/bug?extid=c4113d7fde34d9da20de
compiler: gcc (GCC) 10.1.0-syz 20200507
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1116766f900000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16f9e5d7900000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c4113d...@syzkaller.appspotmail.com

F2FS-fs (loop0): Magic Mismatch, valid(0xf2f52010) - read(0x0)
F2FS-fs (loop0): Can't find valid F2FS filesystem in 1th superblock
F2FS-fs (loop0): Fix alignment : done, start(4096) end(147456) block(12288)
F2FS-fs (loop0): invalid crc value
==================================================================
BUG: KASAN: slab-out-of-bounds in init_min_max_mtime fs/f2fs/segment.c:4161 [inline]
BUG: KASAN: slab-out-of-bounds in f2fs_build_segment_manager+0x8ed7/0xa980 fs/f2fs/segment.c:4243
Read of size 8 at addr ffff8880975e5628 by task syz-executor063/6506

CPU: 1 PID: 6506 Comm: syz-executor063 Not tainted 4.19.150-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+0x22c/0x33e lib/dump_stack.c:118
print_address_description.cold+0x56/0x25c mm/kasan/report.c:256
kasan_report_error.cold+0x66/0xb9 mm/kasan/report.c:354
kasan_report mm/kasan/report.c:412 [inline]
__asan_report_load8_noabort+0x88/0x90 mm/kasan/report.c:433
init_min_max_mtime fs/f2fs/segment.c:4161 [inline]
f2fs_build_segment_manager+0x8ed7/0xa980 fs/f2fs/segment.c:4243
f2fs_fill_super+0x2173/0x7920 fs/f2fs/super.c:3016
mount_bdev+0x2fc/0x3b0 fs/super.c:1158
mount_fs+0xa3/0x318 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+0x51c/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+0xf9/0x670 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x446ffa
Code: b8 08 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 fd ad 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 da ad fb ff c3 66 0f 1f 84 00 00 00 00 00
RSP: 002b:00007ffc88417ad8 EFLAGS: 00000297 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffc88417b30 RCX: 0000000000446ffa
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007ffc88417af0
RBP: 00007ffc88417af0 R08: 00007ffc88417b30 R09: 00007ffc00000015
R10: 0000000000000000 R11: 0000000000000297 R12: 0000000000000008
R13: 0000000000000004 R14: 0000000000000003 R15: 0000000000000003

Allocated by task 6506:
__do_kmalloc_node mm/slab.c:3689 [inline]
__kmalloc_node+0x4c/0x70 mm/slab.c:3696
kmalloc_node include/linux/slab.h:557 [inline]
kvmalloc_node+0x61/0xf0 mm/util.c:423
kvmalloc include/linux/mm.h:577 [inline]
f2fs_kvmalloc fs/f2fs/f2fs.h:2687 [inline]
f2fs_kvzalloc fs/f2fs/f2fs.h:2693 [inline]
build_sit_info fs/f2fs/segment.c:3768 [inline]
f2fs_build_segment_manager+0xd2e/0xa980 fs/f2fs/segment.c:4219
f2fs_fill_super+0x2173/0x7920 fs/f2fs/super.c:3016
mount_bdev+0x2fc/0x3b0 fs/super.c:1158
mount_fs+0xa3/0x318 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+0x51c/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+0xf9/0x670 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 0:
(stack is not available)

The buggy address belongs to the object at ffff8880975e5180
which belongs to the cache kmalloc-2048 of size 2048
The buggy address is located 1192 bytes inside of
2048-byte region [ffff8880975e5180, ffff8880975e5980)
The buggy address belongs to the page:
page:ffffea00025d7900 count:1 mapcount:0 mapping:ffff88812c3f6c40 index:0x0 compound_mapcount: 0
flags: 0xfffe0000008100(slab|head)
raw: 00fffe0000008100 ffffea00025b2388 ffff88812c3f4948 ffff88812c3f6c40
raw: 0000000000000000 ffff8880975e4080 0000000100000003 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff8880975e5500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff8880975e5580: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8880975e5600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
^
ffff8880975e5680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8880975e5700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


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