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| author | Stephen Warren <swarren@nvidia.com> | 2013-05-07 16:53:52 -0600 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-05-16 17:30:52 -0700 |
| commit | 3b9561e9d9b88eca9d4ed6aab025dec2eeeed501 (patch) | |
| tree | 6ac9d662f3b7c4ee4411d4fc5103f1226430740a /drivers/usb/host/ehci-atmel.c | |
| parent | 8ff10bdb14a52e3f25d4ce09e0582a8684c1a6db (diff) | |
| download | linux-3b9561e9d9b88eca9d4ed6aab025dec2eeeed501.tar.gz linux-3b9561e9d9b88eca9d4ed6aab025dec2eeeed501.tar.bz2 linux-3b9561e9d9b88eca9d4ed6aab025dec2eeeed501.zip | |
USB: set device dma_mask without reference to global data
Many USB host drivers contain code such as:
if (!pdev->dev.dma_mask)
pdev->dev.dma_mask = &tegra_ehci_dma_mask;
... where tegra_ehci_dma_mask is a global. I suspect this code originated
in commit 4a53f4e "USB: ehci-tegra: add probing through device tree" and
was simply copied everywhere else.
This works fine when the code is built-in, but can cause a crash when the
code is in a module. The first module load sets up the dma_mask pointer,
but if the module is removed and re-inserted, the value is now non-NULL,
and hence is not updated to point at the new location, and hence points
at a stale location within the previous module load address, which in
turn causes a crash if the pointer is de-referenced.
The simplest way of solving this seems to be to copy the code from
ehci-platform.c, which uses the coherent_dma_mask as the target for the
dma_mask pointer.
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Tony Prisk <linux@prisktech.co.nz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/host/ehci-atmel.c')
| -rw-r--r-- | drivers/usb/host/ehci-atmel.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/drivers/usb/host/ehci-atmel.c b/drivers/usb/host/ehci-atmel.c index 66420097c242..02f4611faa62 100644 --- a/drivers/usb/host/ehci-atmel.c +++ b/drivers/usb/host/ehci-atmel.c @@ -63,8 +63,6 @@ static void atmel_stop_ehci(struct platform_device *pdev) /*-------------------------------------------------------------------------*/ -static u64 at91_ehci_dma_mask = DMA_BIT_MASK(32); - static int ehci_atmel_drv_probe(struct platform_device *pdev) { struct usb_hcd *hcd; @@ -93,7 +91,9 @@ static int ehci_atmel_drv_probe(struct platform_device *pdev) * Once we have dma capability bindings this can go away. */ if (!pdev->dev.dma_mask) - pdev->dev.dma_mask = &at91_ehci_dma_mask; + pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask; + if (!pdev->dev.coherent_dma_mask) + pdev->dev.coherent_dma_mask = DMA_BIT_MASK(32); hcd = usb_create_hcd(driver, &pdev->dev, dev_name(&pdev->dev)); if (!hcd) { |