public inbox for linux-m68k@lists.linux-m68k.org
 help / color / mirror / Atom feed
* Missing get_cycles() has effect on quality of entropy
@ 2013-09-09  9:27 Thorsten Glaser
  0 siblings, 0 replies; only message in thread
From: Thorsten Glaser @ 2013-09-09  9:27 UTC (permalink / raw)
  To: linux-m68k

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

^ permalink raw reply	[flat|nested] only message in thread

only message in thread, other threads:[~2013-09-09  9:28 UTC | newest]

Thread overview: (only message) (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2013-09-09  9:27 Missing get_cycles() has effect on quality of entropy Thorsten Glaser

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox