From: James Sewart jamessewart@arista.com
[ Upstream commit f8bf2aeb651b3460a4b36fd7ba1ba1d31777d35c ]
The number of possible devfns is 256, but pci_add_dma_alias() allocated a bitmap of size 255. Fix this off-by-one error.
This fixes commits 338c3149a221 ("PCI: Add support for multiple DMA aliases") and c6635792737b ("PCI: Allocate dma_alias_mask with bitmap_zalloc()"), but I doubt it was possible to see a problem because it takes 4 64-bit longs (or 8 32-bit longs) to hold 255 bits, and bitmap_zalloc() doesn't save the 255-bit size anywhere.
[bhelgaas: commit log, move #define to drivers/pci/pci.h, include loop limit fix from Qian Cai: https://lore.kernel.org/r/20191218170004.5297-1-cai@lca.pw] Signed-off-by: James Sewart jamessewart@arista.com Signed-off-by: Bjorn Helgaas bhelgaas@google.com Reviewed-by: Logan Gunthorpe logang@deltatee.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/pci/pci.c | 2 +- drivers/pci/pci.h | 3 +++ drivers/pci/search.c | 4 ++-- 3 files changed, 6 insertions(+), 3 deletions(-)
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index fcfaadc774eef..cbf3d3889874c 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -5894,7 +5894,7 @@ EXPORT_SYMBOL_GPL(pci_pr3_present); void pci_add_dma_alias(struct pci_dev *dev, u8 devfn) { if (!dev->dma_alias_mask) - dev->dma_alias_mask = bitmap_zalloc(U8_MAX, GFP_KERNEL); + dev->dma_alias_mask = bitmap_zalloc(MAX_NR_DEVFNS, GFP_KERNEL); if (!dev->dma_alias_mask) { pci_warn(dev, "Unable to allocate DMA alias mask\n"); return; diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index 3f6947ee3324a..273d60cb0762d 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -4,6 +4,9 @@
#include <linux/pci.h>
+/* Number of possible devfns: 0.0 to 1f.7 inclusive */ +#define MAX_NR_DEVFNS 256 + #define PCI_FIND_CAP_TTL 48
#define PCI_VSEC_ID_INTEL_TBT 0x1234 /* Thunderbolt */ diff --git a/drivers/pci/search.c b/drivers/pci/search.c index bade14002fd8a..e4dbdef5aef05 100644 --- a/drivers/pci/search.c +++ b/drivers/pci/search.c @@ -41,9 +41,9 @@ int pci_for_each_dma_alias(struct pci_dev *pdev, * DMA, iterate over that too. */ if (unlikely(pdev->dma_alias_mask)) { - u8 devfn; + unsigned int devfn;
- for_each_set_bit(devfn, pdev->dma_alias_mask, U8_MAX) { + for_each_set_bit(devfn, pdev->dma_alias_mask, MAX_NR_DEVFNS) { ret = fn(pdev, PCI_DEVID(pdev->bus->number, devfn), data); if (ret)