From dfef358bd1beb4e7b5c94eca944be9cd23dfc752 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Mon, 30 Jan 2017 13:15:41 +0100 Subject: [PATCH] PCI/MSI: Don't apply affinity if there aren't enough vectors left MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Bart reported a problem wіth an out of bounds access in the low-level IRQ affinity code, which we root caused to the qla2xxx driver assigning all its MSI-X vectors to the pre and post vectors, and not having any left for the actually spread IRQs. Fix this issue by not asking for affinity assignment when there are no vectors to assign left. Fixes: 402723ad5c62 ("PCI/MSI: Provide pci_alloc_irq_vectors_affinity()") Link: https://lkml.kernel.org/r/1485359225.3093.3.camel@sandisk.com Reported-by: Bart Van Assche Tested-by: Bart Van Assche Signed-off-by: Christoph Hellwig Signed-off-by: Bjorn Helgaas --- drivers/pci/msi.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c index 50c5003295ca..7f73bacf13ed 100644 --- a/drivers/pci/msi.c +++ b/drivers/pci/msi.c @@ -1206,6 +1206,16 @@ int pci_alloc_irq_vectors_affinity(struct pci_dev *dev, unsigned int min_vecs, if (flags & PCI_IRQ_AFFINITY) { if (!affd) affd = &msi_default_affd; + + if (affd->pre_vectors + affd->post_vectors > min_vecs) + return -EINVAL; + + /* + * If there aren't any vectors left after applying the pre/post + * vectors don't bother with assigning affinity. + */ + if (affd->pre_vectors + affd->post_vectors == min_vecs) + affd = NULL; } else { if (WARN_ON(affd)) affd = NULL; -- 2.20.1