error -5 occurred during torturing

[Andreas Eipeldauer]

Hello everyone,
 
I try to verify the proper functionality of a nand chip Cypress S34ML01G1 which should substitute the obsolete
Samsung K9F1G08U0E-SIB0000. Therefore I also use the mtd test tools. Within the mtdtests especially when running the mtd_torturetest an error -5 occurred during torturing.

insmod mtd_torturetest.ko dev=1 check=1 cycles_count=100 gran=10 ebcnt=761 eb=0

mtd_torturetest: Warning: this program is trying to wear out your flash, stop it if this is not wanted.
mtd_torturetest: MTD device: 1
mtd_torturetest: torture 761 eraseblocks (0-760) of mtd1
mtd_torturetest: write verify enabled
mtd_torturetest: error -5 while writing EB 731, written 102400 bytes
mtd_torturetest: finished after 0 erase cycles
mtd_torturetest: error -5 occurred during torturing
=================================================
insmod: error inserting 'mtd_torturetest.ko': -1 Input/output error

The mtd1 partition is not mounted and Linux is running with a initram fs. So there should not be any other access to this partition.

I ran these tests also with the old Samsung chip and the -5 errors also appear but not in that high rate.

Any clue what causes this error?  

Best regards, Andy