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| author | Miles Chen <miles.chen@mediatek.com> | 2017-11-18 00:26:19 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-11-18 01:10:00 +0100 |
| commit | 3aaabbf1c39effa2ac0c11103ed07ef03b0a0d89 (patch) | |
| tree | 59e46e30142dd3882d5100a8ee1fe9a861b53a26 /lib | |
| parent | mm/z3fold.c: use kref to prevent page free/compact race (diff) | |
| download | linux-3aaabbf1c39effa2ac0c11103ed07ef03b0a0d89.tar.xz linux-3aaabbf1c39effa2ac0c11103ed07ef03b0a0d89.zip | |
lib/dma-debug.c: fix incorrect pfn calculation
dma-debug reports the following warning:
WARNING: CPU: 3 PID: 298 at kernel-4.4/lib/dma-debug.c:604
debug _dma_assert_idle+0x1a8/0x230()
DMA-API: cpu touching an active dma mapped cacheline [cln=0x00000882300]
CPU: 3 PID: 298 Comm: vold Tainted: G W O 4.4.22+ #1
Hardware name: MT6739 (DT)
Call trace:
debug_dma_assert_idle+0x1a8/0x230
wp_page_copy.isra.96+0x118/0x520
do_wp_page+0x4fc/0x534
handle_mm_fault+0xd4c/0x1310
do_page_fault+0x1c8/0x394
do_mem_abort+0x50/0xec
I found that debug_dma_alloc_coherent() and debug_dma_free_coherent()
assume that dma_alloc_coherent() always returns a linear address.
However it's possible that dma_alloc_coherent() returns a non-linear
address. In this case, page_to_pfn(virt_to_page(virt)) will return an
incorrect pfn. If the pfn is valid and mapped as a COW page, we will
hit the warning when doing wp_page_copy().
Fix this by calculating pfn for linear and non-linear addresses.
[miles.chen@mediatek.com: v4]
Link: http://lkml.kernel.org/r/1510872972-23919-1-git-send-email-miles.chen@mediatek.com
Link: http://lkml.kernel.org/r/1506484087-1177-1-git-send-email-miles.chen@mediatek.com
Signed-off-by: Miles Chen <miles.chen@mediatek.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/dma-debug.c | 20 |
1 files changed, 18 insertions, 2 deletions
diff --git a/lib/dma-debug.c b/lib/dma-debug.c index ea4cc3dde4f1..1b34d210452c 100644 --- a/lib/dma-debug.c +++ b/lib/dma-debug.c @@ -1495,14 +1495,22 @@ void debug_dma_alloc_coherent(struct device *dev, size_t size, if (!entry) return; + /* handle vmalloc and linear addresses */ + if (!is_vmalloc_addr(virt) && !virt_to_page(virt)) + return; + entry->type = dma_debug_coherent; entry->dev = dev; - entry->pfn = page_to_pfn(virt_to_page(virt)); entry->offset = offset_in_page(virt); entry->size = size; entry->dev_addr = dma_addr; entry->direction = DMA_BIDIRECTIONAL; + if (is_vmalloc_addr(virt)) + entry->pfn = vmalloc_to_pfn(virt); + else + entry->pfn = page_to_pfn(virt_to_page(virt)); + add_dma_entry(entry); } EXPORT_SYMBOL(debug_dma_alloc_coherent); @@ -1513,13 +1521,21 @@ void debug_dma_free_coherent(struct device *dev, size_t size, struct dma_debug_entry ref = { .type = dma_debug_coherent, .dev = dev, - .pfn = page_to_pfn(virt_to_page(virt)), .offset = offset_in_page(virt), .dev_addr = addr, .size = size, .direction = DMA_BIDIRECTIONAL, }; + /* handle vmalloc and linear addresses */ + if (!is_vmalloc_addr(virt) && !virt_to_page(virt)) + return; + + if (is_vmalloc_addr(virt)) + ref.pfn = vmalloc_to_pfn(virt); + else + ref.pfn = page_to_pfn(virt_to_page(virt)); + if (unlikely(dma_debug_disabled())) return; |