Comment 44 for bug 1215513

And some explanation (I use another bugreports)
Just comment here, #25 : https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1215513/comments/25

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[ 1.659040] Adding 1025396k swap on /dev/zram0. Priority:100 extents:1 across:1025396k SS
[ 20.719906] Buffer I/O error on device zram0, logical block 256349
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Lets try to calculate:

(what a pity, I can not see bites, only kilobites! but...)

(block ) 256349 * 4 (four kilobites per page) = 1025396k (place of "bad" sector); as you can see, it is the last sector : ""[1.659040] Adding 1025396k swap on /dev/zram0"

Time of this error can be random.... When OS try to use this "last zram sector", it freezes or somethind else...