From: Thorsten Glaser <tg@mirbsd.de>
To: linux-m68k@vger.kernel.org
Subject: Missing get_cycles() has effect on quality of entropy
Date: Mon, 9 Sep 2013 09:27:52 +0000 (UTC) [thread overview]
Message-ID: <loom.20130909T112514-903@post.gmane.org> (raw)
Hi!
https://lists.openwrt.org/pipermail/openwrt-devel/2013-September/021318.html
affects several architectures – m68k among them.
Some arches have comments like “only used by the scheduler”. This may
have been once true, but a quick “git grep -w get_cycles” shows much
more use throughout the Linux kernel.
The random thing is scary already, but…
mm/slub.c: p += 64 + (get_cycles() & 0xff) * sizeof(void *);
… there are several cases like this, where an always-zero get_cycles()
result severely impacts operation of the code.
So I ask whether it’s possible to fill this code with life, for at
least a subset of all architectures?
bye,
//mirabilos
reply other threads:[~2013-09-09 9:28 UTC|newest]
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