I had removed it from my kernel because I didn't know what it did
Which is why you should start with a known-good config, especially if you don't understand what the options in the kernel mean. Hell in this case the help text for the option states that it will populate the /proc/sys tree if you have procfs support enabled and to only disable it if you have a very good reason.
Read the hibernate.log file or possibly dmesg, one of them should mention which process refused to freeze. I had it freeze at that point one time myself, attempting to hibernate a second time worked fine. I assume that the sync took too long and caused suspend2 to abort, since there was less work to do the second time it completed just fine.