linux-kernel - RE: "double" hpet clocksource && hard freeze [bisected]

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <617E1C2C70743745A92448908E030B2A023EB8C4@scsmsx411.amr.corp.intel.com>
Date:	Fri, 24 Aug 2007 09:04:22 -0700
From:	"Luck, Tony" <tony.luck@...el.com>
To:	"Paolo Ornati" <ornati@...twebnet.it>,
	"Bob Picco" <bob.picco@...com>
Cc:	"john stultz" <johnstul@...ibm.com>,
	"Linux Kernel Mailing List" <linux-kernel@...r.kernel.org>,
	"Bob Picco" <bob.picco@...com>
Subject: RE: "double" hpet clocksource && hard freeze [bisected]

> > Prevent duplicate names being registered with clocksource. This also
> > eliminates the duplication of hpet clock registration when the arch
> > uses the hpet timer and the hpet driver does too. The patch was
> > compile and link tested.
>
> This one works too.

It is good to avoid registering two clocksources with the same name, but
the fix might be a bit more fragile than the eariler one that temporarily
marked the drivers/char/hpet.c one as CONFIG_IA64 only.  Given that the
hang went away when you applied the earlier patch, I conclude that the
drivers/char/hpet.c code is the one that got selected when you had two
"hpet" entries ... and that there is something wrong with that code that
doesn't work right on x86_64.  The fix to prevent registering a duplicate
name is presumably working for you simply because arch/x86_64/kernel/hpet.c
happens to get there first with its "hpet", so the drivers/char/hpet.c one
is dropped.  If something changed that reversed the order of these registrations,
then you'd get the "hpet" clocksource that results in a hang.

-Tony
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/