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: stable@vger.kernel.org Link: https://lore.kernel.org/r/87sfw5305m.ffs@tglx --- Backport v4.4.y and v4.9.y --- drivers/pci/msi.c | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-)
--- a/drivers/pci/msi.c +++ b/drivers/pci/msi.c @@ -390,18 +390,6 @@ 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); - kfree(entry); - } - if (dev->msi_irq_groups) { sysfs_remove_groups(&dev->dev.kobj, dev->msi_irq_groups); msi_attrs = dev->msi_irq_groups[0]->attrs; @@ -417,6 +405,18 @@ 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)