[PATCH 5.14 10/15] PCI/MSI: Destroy sysfs before freeing entries

Greg Kroah-Hartman
2021-11-19T17:39:12Z

From: Thomas Gleixner <tglx@linutronix.de>

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>

---
drivers/pci/msi.c | 24 ++++++++++++------------
1 file changed, 12 insertions(+), 12 deletions(-)

--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -368,18 +368,6 @@ static void free_msi_irqs(struct pci_dev
for (i = 0; i < entry->nvec_used; i++)
BUG_ON(irq_has_action(entry->irq + i));

- pci_msi_teardown_msi_irqs(dev);
-
- list_for_each_entry_safe(entry, tmp, msi_list, list) {
- if (entry->msi_attrib.is_msix) {
- if (list_is_last(&entry->list, msi_list))
- iounmap(entry->mask_base);
- }
-
- list_del(&entry->list);
- free_msi_entry(entry);
- }
-
if (dev->msi_irq_groups) {
sysfs_remove_groups(&dev->dev.kobj, dev->msi_irq_groups);
msi_attrs = dev->msi_irq_groups[0]->attrs;
@@ -395,6 +383,18 @@ static void free_msi_irqs(struct pci_dev
kfree(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) {
+ if (entry->msi_attrib.is_msix) {
+ if (list_is_last(&entry->list, msi_list))
+ iounmap(entry->mask_base);
+ }
+
+ list_del(&entry->list);
+ free_msi_entry(entry);
+ }
}

static void pci_intx_for_msi(struct pci_dev *dev, int enable)