From: Mika Westerberg <mika.westerberg@linux.intel.com>
To: Lukas Wunner <lukas@wunner.de>
Cc: Bjorn Helgaas <bhelgaas@google.com>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
Keith Busch <keith.busch@intel.com>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Frederick Lawler <fred@fredlawl.com>,
"Gustavo A . R . Silva" <gustavo@embeddedor.com>,
Sinan Kaya <okaya@kernel.org>,
Kai-Heng Feng <kai.heng.feng@canonical.com>,
linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 2/2] PCI: pciehp: Prevent deadlock on disconnect
Date: Mon, 23 Sep 2019 11:28:32 +0300 [thread overview]
Message-ID: <20190923082832.GD2773@lahna.fi.intel.com> (raw)
In-Reply-To: <20190923081237.GB2773@lahna.fi.intel.com>
On Mon, Sep 23, 2019 at 11:12:42AM +0300, Mika Westerberg wrote:
> Regarding suggestion of unbinding PCI drivers without
> pci_lock_rescan_remove() hold, I haven't looked it too closely but I
> think we need to take that lock anyway because when we are unbinding a
> hotplug driver it is supposed to remove the hierarchy below touching the
> shared structures, possibly concurrently. Unfortunately there is no
> documentation what data pci_lock_rescan_remove() actually protects so
> first one needs to understand that. I think one way to clean up this is
> to use finer grained locking (with documented lock ordering) for PCI bus
> structures that can be accessed simultaneusly by different threads. But
> that is not a simple task.
Now that I looked more closely, I realized it actually is not supposed
to remove the hierarchy below so indeed it might be possible to do that
without taking pci_lock_rescan_remove().
next prev parent reply other threads:[~2019-09-23 8:28 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-12 14:31 [PATCH v2 1/2] PCI: pciehp: Do not disable interrupt twice on suspend Mika Westerberg
2019-08-12 14:31 ` [PATCH v2 2/2] PCI: pciehp: Prevent deadlock on disconnect Mika Westerberg
2019-08-19 2:28 ` Sinan Kaya
2019-08-19 8:56 ` Mika Westerberg
2019-08-19 12:28 ` Sinan Kaya
2019-09-23 5:34 ` Lukas Wunner
2019-09-23 8:12 ` Mika Westerberg
2019-09-23 8:28 ` Lukas Wunner
2019-09-23 8:28 ` Mika Westerberg [this message]
2019-10-18 7:10 ` Kai-Heng Feng
2019-10-22 23:00 ` Bjorn Helgaas
2019-10-23 7:52 ` Mika Westerberg
2019-10-24 9:38 ` Mika Westerberg
2019-10-24 17:11 ` Bjorn Helgaas
2019-09-19 6:42 ` [PATCH v2 1/2] PCI: pciehp: Do not disable interrupt twice on suspend Mika Westerberg
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