On Thu, Jul 12, 2007 at 04:16:24PM -0600, Andreas Dilger wrote: > On Jul 12, 2007 13:09 +0200, Andi Kleen wrote: > > > "dd if=/dev/urandom bs=1k ..." than to spin in a loop getting 16-bit > > > random numbers from bash. We would also be at the mercy of the shell > > > being identical on the user and debugger's systems. > > > > With /dev/urandom you have the guarantee you'll never ever reproduce > > it again. > > That is kind of the point of this testing - getting new test images for > each user that runs "make check" or "make rpm". I'm We also save the > generated image before e2fsck touches it so that it can be used for > debugging if needed. If you seed a good pseudo RNG with the time (or even a few bytes from /dev/urandom; although the time tends to work as well) you'll also effectively get a new image every time. But the advantage is if you print out the seed the image can be easily recreated just by re-running the fuzzer with the same seed. No need to ship potentially huge images around. You can essentially compress your whole image into a single number this way. -Andi - To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
