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    Subject[PATCH 4.19 254/323] PCI/MSI: Destroy sysfs before freeing entries
    Date
    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
    @@ -372,18 +372,6 @@ 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;
    @@ -399,6 +387,18 @@ 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)

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