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Message-Id: <1523972123-5700-1-git-send-email-jacopo+renesas@jmondi.org>
Date: Tue, 17 Apr 2018 15:35:23 +0200
From: Jacopo Mondi <jacopo+renesas@...ndi.org>
To: ysato@...rs.sourceforge.jp, dalias@...c.org,
thomas.petazzoni@...e-electrons.com, robin.murphy@....com
Cc: Jacopo Mondi <jacopo+renesas@...ndi.org>, geert@...ux-m68k.org,
linux-renesas-soc@...r.kernel.org, linux-sh@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: [PATCH] sh: mm: Fix unprotected access to struct device
With commit ce88313069c36eef80f21fd7 ("arch/sh: make the DMA mapping
operations observe dev->dma_pfn_offset") the generic DMA allocation
function on which the SH 'dma_alloc_coherent()' function relies on,
access the 'dma_pfn_offset' field of struct device.
Unfortunately the 'dma_generic_alloc_coherent()' function is called from
several places with a NULL struct device argument, halting the CPU
during the boot process.
This patch fixes the issue protecting access to dev->dma_pfn_offset,
with a trivial check for validity. It also passes a valid 'struct device'
in the 'platform_resource_setup_memory' function which is the main user
of 'dma_alloc_coherent()', and inserting a WARN_ON() check to make future
(and existing) bogus users of this function they're should provide a valid
'struct device' whenever possible.
Fixes: ce88313069c36eef80f21fd7 ("arch/sh: make the DMA mapping operations observe dev->dma_pfn_offset")
Signed-off-by: Jacopo Mondi <jacopo+renesas@...ndi.org>
---
arch/sh/mm/consistent.c | 15 ++++++++++++---
1 file changed, 12 insertions(+), 3 deletions(-)
diff --git a/arch/sh/mm/consistent.c b/arch/sh/mm/consistent.c
index 8ce9869..b257155 100644
--- a/arch/sh/mm/consistent.c
+++ b/arch/sh/mm/consistent.c
@@ -39,6 +39,8 @@ void *dma_generic_alloc_coherent(struct device *dev, size_t size,
void *ret, *ret_nocache;
int order = get_order(size);
+ WARN_ON(!dev);
+
gfp |= __GFP_ZERO;
ret = (void *)__get_free_pages(gfp, order);
@@ -59,7 +61,9 @@ void *dma_generic_alloc_coherent(struct device *dev, size_t size,
split_page(pfn_to_page(virt_to_phys(ret) >> PAGE_SHIFT), order);
- *dma_handle = virt_to_phys(ret) - PFN_PHYS(dev->dma_pfn_offset);
+ *dma_handle = virt_to_phys(ret);
+ if (dev)
+ *dma_handle -= PFN_PHYS(dev->dma_pfn_offset);
return ret_nocache;
}
@@ -69,9 +73,14 @@ void dma_generic_free_coherent(struct device *dev, size_t size,
unsigned long attrs)
{
int order = get_order(size);
- unsigned long pfn = (dma_handle >> PAGE_SHIFT) + dev->dma_pfn_offset;
+ unsigned long pfn = (dma_handle >> PAGE_SHIFT);
int k;
+ WARN_ON(!dev);
+
+ if (dev)
+ pfn += dev->dma_pfn_offset;
+
for (k = 0; k < (1 << order); k++)
__free_pages(pfn_to_page(pfn + k), 0);
@@ -143,7 +152,7 @@ int __init platform_resource_setup_memory(struct platform_device *pdev,
if (!memsize)
return 0;
- buf = dma_alloc_coherent(NULL, memsize, &dma_handle, GFP_KERNEL);
+ buf = dma_alloc_coherent(&pdev->dev, memsize, &dma_handle, GFP_KERNEL);
if (!buf) {
pr_warning("%s: unable to allocate memory\n", name);
return -ENOMEM;
--
2.7.4
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