738 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 739 {
[...]
1066     ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY);
1067     return 0;

 576 static int ext2_setup_super (struct super_block * sb,
 577                   struct ext2_super_block * es,
 578                   int read_only)
 579 {
 580     int res = 0;
 581     struct ext2_sb_info *sbi = EXT2_SB(sb);
 582      
 583     if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
 584         printk ("EXT2-fs warning: revision level too high, "
 585             "forcing read-only mode\n");
 586         res = MS_RDONLY;
 587     }
[...]
 618     return res;
 619 }

It doesn't look like this piece of code is tested at all. The status returned from ext2_setup_super is not checked at all, so what it did was to print a warning message. I believe this should be done in the early part of ext2_fill_super().

Updating PM score.

I don't think this is a critical fix for RHEL at this point.