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From: Daniel Walker <dwalker@mvista.com>
To: "Moore, Robert" <robert.moore@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>,
	"Zhao, Yakui" <yakui.zhao@intel.com>,
	linux-acpi@vger.kernel.org, Ingo Molnar <mingo@elte.hu>,
	Peter Zijlstra <peterz@infradead.org>,
	"Brown, Len" <len.brown@intel.com>
Subject: RE: [PATCH 1/3] acpi: add real mutex function calls
Date: Thu, 24 Jul 2008 08:44:21 -0400	[thread overview]
Message-ID: <1216903461.29701.11.camel@localhost.localdomain> (raw)
In-Reply-To: <9D39833986E69849A2A8E74C1078B6B3B6925F@orsmsx415.amr.corp.intel.com>

(Added back the CC list.)

I don't think the problem is in the machine specific ACPI info .. As far
as I can tell the problem is related to how the interpreter lock is
interleaved with the AML mutexes . For example, a series of AML locks
can be A->B->C and at any point the interpreter lock can be released,
and reacquired. So you have a possible lock sequence of I->A->B->C ,
then in another path you have A->I->B->C. That creates a circular lock
scenario and with multiple threads in those different paths you could
end up with a deadlock (or a lockdep warning).

I was also reading the ACPI spec on how the ASL compiler does checking
on mutex usage similar to what lockdep is doing. I would hope there are
no lockdep warning coming from that code.

Daniel


      reply	other threads:[~2008-07-24 12:45 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-07-19 18:16 [PATCH 0/3] acpi: acpi: sem out, mutex/completion in Daniel Walker
2008-07-19 18:16 ` [PATCH 1/3] acpi: add real mutex function calls Daniel Walker
2008-07-19 18:16   ` [PATCH 2/3] acpi: semaphore removal Daniel Walker
2008-07-19 18:16     ` [PATCH 3/3] Add lockdep integration for the ACPI mutex usage Daniel Walker
2008-07-20  8:15     ` [PATCH 2/3] acpi: semaphore removal Dave Chinner
2008-07-20 14:49       ` Daniel Walker
2008-07-21  1:51   ` [PATCH 1/3] acpi: add real mutex function calls Zhao Yakui
2008-07-21  9:14     ` Peter Zijlstra
2008-07-21  9:17       ` Andi Kleen
2008-07-21  9:24         ` Peter Zijlstra
2008-07-21 19:15           ` Andi Kleen
2008-07-21 19:33             ` Peter Zijlstra
2008-07-21 19:55               ` Matthew Wilcox
2008-07-21 20:22                 ` Daniel Walker
2008-07-21 20:00               ` Andi Kleen
2008-07-21 20:38                 ` Daniel Walker
2008-07-21 13:59         ` Daniel Walker
2008-07-21 13:56     ` Daniel Walker
2008-07-21 19:20       ` Andi Kleen
2008-07-21 19:39         ` Daniel Walker
2008-07-23 22:14           ` Moore, Robert
2008-07-24 12:44             ` Daniel Walker [this message]

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