tree 4470c1ccd9ade767d3c3928ebb2432e9c9d32546
parent d6d211db37e75de2ddc3a4f979038c40df7cc79c
author Theodore Ts'o <tytso@mit.edu> 1400290841 -0400
committer Theodore Ts'o <tytso@mit.edu> 1400293102 -0400

random: fix BUG_ON caused by accounting simplification

Commit ee1de406ba6eb1 ("random: simplify accounting logic") simplified
things too much, in that it allows the following to trigger an
overflow that results in a BUG_ON crash:

dd if=/dev/urandom of=/dev/zero bs=67108707 count=1

Thanks to Peter Zihlstra for discovering the crash, and Hannes
Frederic for analyizing the root cause.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reported-by: Peter Zijlstra <peterz@infradead.org>
Reported-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Cc: Greg Price <price@mit.edu>