i'm using gentoo kernel sources, root filesystem type ext3.

somtimes during untarring archives corrupted files are created. stat returns an io-error on these files.

this happens especially when a parallel process accesses the disc device (df is a good one to reproduce this behavior). 
i don't get any kernel error message so i figure my hardware is ok (and yes, i turned off log caching ;).

do you know this problem or even the cause of it ?

i had "preemtive kernel" enabled and i disabled it now (this was the only suspicious entry in the kernel config i could find, for now).
(of course i'll post if disabling kernel preemtion solved the problem and post a full bug report in case it happens again).