From: "Rafael J. Wysocki" <rjw@sisk.pl>
To: "Moore, Robert" <robert.moore@intel.com>
Cc: Toshi Kani <toshi.kani@hp.com>,
ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Bjorn Helgaas <bhelgaas@google.com>, Jiang Liu <liuj97@gmail.com>,
Yinghai Lu <yinghai@kernel.org>,
Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>,
Myron Stowe <mstowe@redhat.com>,
"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>
Subject: Re: [Update][PATCH] ACPI / hotplug: Fix concurrency issues and memory leaks
Date: Thu, 14 Feb 2013 13:03:57 +0100 [thread overview]
Message-ID: <7010893.9OBeMt5Fzh@vostro.rjw.lan> (raw)
In-Reply-To: <94F2FBAB4432B54E8AACC7DFDE6C92E368CB39A9@ORSMSX101.amr.corp.intel.com>
On Thursday, February 14, 2013 02:31:22 AM Moore, Robert wrote:
> > > > I thought about that, but actually there's no guarantee that the
> > > > handle will be valid after _EJ0 as far as I can say. So the race
> > > > condition is going to be there anyway and using struct acpi_device
> > > > just makes it easier to avoid it.
> > >
> > > In theory, yes, a stale handle could be a problem, if _EJ0 performs
> > > unload table and if ACPICA frees up its internal data structure
> > > pointed by the handle as a result. But we should not see such issue
> > > now since we do not support dynamic ACPI namespace yet.
> >
> > I'm waiting for information from Bob about that. If we can assume ACPI
> > handles to be always valid, that will simplify things quite a bit.
>
> If a table is unloaded, all the namespace nodes for that table are removed
> from the namespace, and thus any ACPI_HANDLE pointers go stale and invalid.
OK, thanks!
To me this means that we cannot assume a handle to stay valid between
a notify handler and acpi_bus_hot_remove_device() run from a workqueue.
Is there a mechanism in ACPICA to ensure that a handle won't become stale while
a notify handler is running for it or is the OS responsible for ensuring that
_EJ0 won't be run in parallel with notify handlers for device objects being
ejected?
Rafael
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
next prev parent reply other threads:[~2013-02-14 11:57 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-13 0:19 [PATCH] ACPI / hotplug: Fix concurrency issues and memory leaks Rafael J. Wysocki
2013-02-13 1:55 ` Yinghai Lu
2013-02-13 13:08 ` Rafael J. Wysocki
2013-02-13 3:08 ` Yasuaki Ishimatsu
2013-02-13 3:31 ` Yasuaki Ishimatsu
2013-02-13 13:12 ` Rafael J. Wysocki
2013-02-13 13:16 ` [Update][PATCH] " Rafael J. Wysocki
2013-02-13 17:43 ` Toshi Kani
2013-02-13 20:52 ` Rafael J. Wysocki
2013-02-13 23:09 ` Toshi Kani
2013-02-13 23:42 ` Rafael J. Wysocki
2013-02-14 0:16 ` Toshi Kani
2013-02-14 2:31 ` Moore, Robert
2013-02-14 12:03 ` Rafael J. Wysocki [this message]
2013-02-14 20:45 ` Moore, Robert
2013-02-14 20:59 ` Rafael J. Wysocki
2013-02-14 23:45 ` Moore, Robert
2013-02-15 0:23 ` Rafael J. Wysocki
2013-02-15 0:28 ` Toshi Kani
2013-02-15 12:49 ` Rafael J. Wysocki
2013-02-15 15:18 ` Toshi Kani
2013-02-15 16:33 ` Moore, Robert
2013-02-15 17:22 ` Toshi Kani
2013-02-14 20:05 ` Yinghai Lu
2013-02-14 20:17 ` Rafael J. Wysocki
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