UBSAN: shift-out-of-bounds in erofs_fc_fill_super

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: b3a3cbde Add linux-next specific files for 20210115
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=1060b83b500000
kernel config: https://syzkaller.appspot.com/x/.config?x=6ea08dae6aab586f
dashboard link: https://syzkaller.appspot.com/bug?extid=c68f467cd7c45860e8d4
compiler: gcc (GCC) 10.1.0-syz 20200507
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15fd46af500000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16e2a858d00000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c68f46...@syzkaller.appspotmail.com

loop0: detected capacity change from 4 to 0
================================================================================
UBSAN: shift-out-of-bounds in fs/erofs/super.c:161:3
shift exponent 59 is too large for 32-bit type 'int'
CPU: 1 PID: 8462 Comm: syz-executor591 Not tainted 5.11.0-rc3-next-20210115-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:79 [inline]
dump_stack+0x107/0x163 lib/dump_stack.c:120
ubsan_epilogue+0xb/0x5a lib/ubsan.c:148
__ubsan_handle_shift_out_of_bounds.cold+0xb1/0x181 lib/ubsan.c:395
erofs_read_superblock fs/erofs/super.c:161 [inline]
erofs_fc_fill_super.cold+0x6c/0x35c fs/erofs/super.c:357
get_tree_bdev+0x440/0x760 fs/super.c:1291
vfs_get_tree+0x89/0x2f0 fs/super.c:1496
do_new_mount fs/namespace.c:2889 [inline]
path_mount+0x12ae/0x1e70 fs/namespace.c:3220
do_mount fs/namespace.c:3233 [inline]
__do_sys_mount fs/namespace.c:3441 [inline]
__se_sys_mount fs/namespace.c:3418 [inline]
__x64_sys_mount+0x27f/0x300 fs/namespace.c:3418
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x446d1a
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:00007fff68419868 EFLAGS: 00000297 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fff684198c0 RCX: 0000000000446d1a
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007fff68419880
RBP: 00007fff68419880 R08: 00007fff684198c0 R09: 00007fff00000015
R10: 0000000000000000 R11: 0000000000000297 R12: 0000000000000001
R13: 0000000000000004 R14: 0000000000000003 R15: 0000000000000003
================================================================================


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
syzbot can test patches for this issue, for details see:
https://goo.gl/tpsmEJ#testing-patches