[PATCH 5.15 856/917] PCI/MSI: Destroy sysfs before freeing entries

Greg Kroah-Hartman
2021-11-16T00:37:10Z

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 | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -368,6 +368,11 @@ static void free_msi_irqs(struct pci_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
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)