Patch "powerpc/msi: Fix deassociation of MSI descriptors" has been added to the 4.9-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    powerpc/msi: Fix deassociation of MSI descriptors

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     powerpc-msi-fix-deassociation-of-msi-descriptors.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 760aa3717faf046c8d5bdc27c226179d192b7ddf
Author: Marc Zyngier <maz@xxxxxxxxxx>
Date:   Sat Dec 17 10:46:44 2022 +0000

    powerpc/msi: Fix deassociation of MSI descriptors
    
    [ Upstream commit 4545c6a3d6ba71747eaa984c338ddd745e56e23f ]
    
    Since 2f2940d16823 ("genirq/msi: Remove filter from
    msi_free_descs_free_range()"), the core MSI code relies on the
    msi_desc->irq field to have been cleared before the descriptor
    can be freed, as it indicates that there is no association with
    a device anymore.
    
    The irq domain code provides this guarantee, and so does s390,
    which is one of the two architectures not using irq domains for
    MSIs.
    
    Powerpc, however, is missing this particular requirements,
    leading in a splat and leaked MSI descriptors.
    
    Adding the now required irq reset to the handful of powerpc backends
    that implement MSIs fixes that particular problem.
    
    Reported-by: Guenter Roeck <linux@xxxxxxxxxxxx>
    Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
    Link: https://lore.kernel.org/r/70dab88e-6119-0c12-7c6a-61bcbe239f66@xxxxxxxxxxxx
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/arch/powerpc/platforms/cell/axon_msi.c b/arch/powerpc/platforms/cell/axon_msi.c
index 8b55c5f19d4c..f78dc043f370 100644
--- a/arch/powerpc/platforms/cell/axon_msi.c
+++ b/arch/powerpc/platforms/cell/axon_msi.c
@@ -298,6 +298,7 @@ static void axon_msi_teardown_msi_irqs(struct pci_dev *dev)
 
 		irq_set_msi_desc(entry->irq, NULL);
 		irq_dispose_mapping(entry->irq);
+		entry->irq = 0;
 	}
 }
 
diff --git a/arch/powerpc/platforms/pasemi/msi.c b/arch/powerpc/platforms/pasemi/msi.c
index d9cd510c8865..6e54377663db 100644
--- a/arch/powerpc/platforms/pasemi/msi.c
+++ b/arch/powerpc/platforms/pasemi/msi.c
@@ -74,6 +74,7 @@ static void pasemi_msi_teardown_msi_irqs(struct pci_dev *pdev)
 		hwirq = virq_to_hw(entry->irq);
 		irq_set_msi_desc(entry->irq, NULL);
 		irq_dispose_mapping(entry->irq);
+		entry->irq = 0;
 		msi_bitmap_free_hwirqs(&msi_mpic->msi_bitmap, hwirq, ALLOC_CHUNK);
 	}
 
diff --git a/arch/powerpc/sysdev/fsl_msi.c b/arch/powerpc/sysdev/fsl_msi.c
index 8a244828782e..aa9dd3a92f2a 100644
--- a/arch/powerpc/sysdev/fsl_msi.c
+++ b/arch/powerpc/sysdev/fsl_msi.c
@@ -137,6 +137,7 @@ static void fsl_teardown_msi_irqs(struct pci_dev *pdev)
 		msi_data = irq_get_chip_data(entry->irq);
 		irq_set_msi_desc(entry->irq, NULL);
 		irq_dispose_mapping(entry->irq);
+		entry->irq = 0;
 		msi_bitmap_free_hwirqs(&msi_data->bitmap, hwirq, 1);
 	}
 
diff --git a/arch/powerpc/sysdev/mpic_u3msi.c b/arch/powerpc/sysdev/mpic_u3msi.c
index cfc1c57d760f..26db91c8feff 100644
--- a/arch/powerpc/sysdev/mpic_u3msi.c
+++ b/arch/powerpc/sysdev/mpic_u3msi.c
@@ -116,6 +116,7 @@ static void u3msi_teardown_msi_irqs(struct pci_dev *pdev)
 		hwirq = virq_to_hw(entry->irq);
 		irq_set_msi_desc(entry->irq, NULL);
 		irq_dispose_mapping(entry->irq);
+		entry->irq = 0;
 		msi_bitmap_free_hwirqs(&msi_mpic->msi_bitmap, hwirq, 1);
 	}
 
diff --git a/arch/powerpc/sysdev/ppc4xx_hsta_msi.c b/arch/powerpc/sysdev/ppc4xx_hsta_msi.c
index 9926ad67af76..ac5fbb2492aa 100644
--- a/arch/powerpc/sysdev/ppc4xx_hsta_msi.c
+++ b/arch/powerpc/sysdev/ppc4xx_hsta_msi.c
@@ -121,6 +121,7 @@ static void hsta_teardown_msi_irqs(struct pci_dev *dev)
 		msi_bitmap_free_hwirqs(&ppc4xx_hsta_msi.bmp, irq, 1);
 		pr_debug("%s: Teardown IRQ %u (index %u)\n", __func__,
 			 entry->irq, irq);
+		entry->irq = 0;
 	}
 }