From: Corey Minyard <minyard@acm.org>
To: "Maciej W. Rozycki" <macro@linux-mips.org>
Cc: Andi Kleen <ak@suse.de>, linux-kernel@vger.kernel.org
Subject: Re: Race betwen the NMI handler and the RTC clock in practially all kernels II
Date: Mon, 25 Oct 2004 21:50:02 -0500 [thread overview]
Message-ID: <417DBB5A.6020207@acm.org> (raw)
In-Reply-To: <Pine.LNX.4.58L.0410260031050.10974@blysk.ds.pg.gda.pl>
Maciej W. Rozycki wrote:
>>And you need a mutex for SMP systems. If one processor is handling an
>>NMI, another processor may still be accessing the device.
>>
>>
> Actually this path is meant to be ever accessed by one CPU only (one that
>has its LINT1 line enabled), but it may be reached by other ones due to
>the NMI watchdog as code does not check if its run by the right processor.
>This probably qualifies as a bug. Only the watchdog code of the NMI
>handler is expected to run everywhere.
>
>
Yes, only one processor will run through the NMI code, but another
processor may be accessing the RTC or something else in CMOS. The mutex
will prevent the NMI and the RTC access from conflicting.
-Corey
next prev parent reply other threads:[~2004-10-26 2:57 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <417D2305.3020209@acm.org.suse.lists.linux.kernel>
2004-10-25 19:44 ` Race betwen the NMI handler and the RTC clock in practially all kernels Andi Kleen
2004-10-25 19:50 ` Corey Minyard
2004-10-25 20:14 ` Andi Kleen
2004-10-25 20:15 ` linux-os
2004-10-25 20:07 ` Maciej W. Rozycki
2004-10-25 20:17 ` Andi Kleen
2004-10-25 20:41 ` Race betwen the NMI handler and the RTC clock in practially all kernels II Andi Kleen
2004-10-25 21:00 ` Maciej W. Rozycki
2004-10-25 22:04 ` Corey Minyard
2004-10-25 23:40 ` Maciej W. Rozycki
2004-10-26 2:50 ` Corey Minyard [this message]
2004-10-26 12:01 ` linux-os
2004-10-25 20:47 ` Race betwen the NMI handler and the RTC clock in practially all kernels Maciej W. Rozycki
2004-10-25 20:11 ` linux-os
2004-10-25 20:23 ` Andi Kleen
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