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[V3,1/2] PCI: Try to clean up resources via remove if shutdown doesn't exist

Message ID 1527542471-10316-1-git-send-email-okaya@codeaurora.org (mailing list archive)
State New, archived
Delegated to: Bjorn Helgaas
Headers show

Commit Message

Sinan Kaya May 28, 2018, 9:21 p.m. UTC
It is up to a driver to implement shutdown() callback. If shutdown()
callback is not implemented, PCI device can have pending interrupt and
even do DMA transactions while the system is going down.

If kexec is in use, this can damage the newly booting kexec kernel
or even prevent it from booting altogether. Fallback to calling the
remove() callback if shutdown() isn't implemented for a given driver.

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=199779
Fixes: cc27b735ad3a ("PCI/portdrv: Turn off PCIe services during shutdown")
Cc: stable@vger.kernel.org
Reported-by: Ryan Finnie <ryan@finnie.org>
---
 drivers/pci/pci-driver.c | 9 +++++++++
 1 file changed, 9 insertions(+)

Comments

Ryan Finnie May 30, 2018, 1:49 a.m. UTC | #1
On 05/28/2018 02:21 PM, Sinan Kaya wrote:
> It is up to a driver to implement shutdown() callback. If shutdown()
> callback is not implemented, PCI device can have pending interrupt and
> even do DMA transactions while the system is going down.
> 
> If kexec is in use, this can damage the newly booting kexec kernel
> or even prevent it from booting altogether. Fallback to calling the
> remove() callback if shutdown() isn't implemented for a given driver.
> 
> Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=199779
> Fixes: cc27b735ad3a ("PCI/portdrv: Turn off PCIe services during shutdown")
> Cc: stable@vger.kernel.org
> Reported-by: Ryan Finnie <ryan@finnie.org>

Tested successfully on DL360 Gen9 and DL380 Gen9.

Tested-by: Ryan Finnie <ryan@finnie.org>
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Patch

diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index cbda0e6..75a00fe 100644
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -477,8 +477,17 @@  static void pci_device_shutdown(struct device *dev)
 
 	pm_runtime_resume(dev);
 
+	/*
+	 * Try shutdown callback if it exists, otherwise fallback to remove
+	 * callback. PCI drivers can do DMA and have pending interrupts.
+	 * Leaving the DMA and interrupts pending could damage the newly
+	 * booting kexec kernel as well as prevent it from booting altogether
+	 * if the pending interrupt is level.
+	 */
 	if (drv && drv->shutdown)
 		drv->shutdown(pci_dev);
+	else if (drv && drv->remove)
+		drv->remove(pci_dev);
 
 	/*
 	 * If this is a kexec reboot, turn off Bus Master bit on the