PCI/MSI: Destroy sysfs before freeing entries

BugLink: https://bugs.launchpad.net/bugs/1951822
commit 3735459037114d31e5acd9894fad9aed104231a0 upstream.

free_msi_irqs() frees the MSI entries before destroying the sysfs entries
which are exposing them. Nothing prevents a concurrent free while a sysfs
file is read and accesses the possibly freed entry.

Move the sysfs release ahead of freeing the entries.

Fixes: 1c51b50c2995 ("PCI/MSI: Export MSI mode using attributes, not kobjects")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Bjorn Helgaas <helgaas@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/87sfw5305m.ffs@tglx
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>

diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index bc64fa51de1dab8c26084455378ef9e98e2944a0..ea6371eb9b257959c3b0ad1d243cf28536caa6dc 100644 (file)
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -368,6 +368,11 @@ static void free_msi_irqs(struct pci_dev *dev)
                        for (i = 0; i < entry->nvec_used; i++)
                                BUG_ON(irq_has_action(entry->irq + i));
 
+       if (dev->msi_irq_groups) {
+               msi_destroy_sysfs(&dev->dev, dev->msi_irq_groups);
+               dev->msi_irq_groups = NULL;
+       }
+
        pci_msi_teardown_msi_irqs(dev);
 
        list_for_each_entry_safe(entry, tmp, msi_list, list) {
@@ -379,11 +384,6 @@ static void free_msi_irqs(struct pci_dev *dev)
                list_del(&entry->list);
                free_msi_entry(entry);
        }
-
-       if (dev->msi_irq_groups) {
-               msi_destroy_sysfs(&dev->dev, dev->msi_irq_groups);
-               dev->msi_irq_groups = NULL;
-       }
 }
 
 static void pci_intx_for_msi(struct pci_dev *dev, int enable)