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dma-debug: fix physical address calculation for struct dma_debug_entry

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Offset into the page should also be considered while calculating a physical
address for struct dma_debug_entry. page_to_phys() just shifts the value
PAGE_SHIFT bits to the left so offset part is zero-filled.

An example (wrong) debug assertion failure with CONFIG_DMA_API_DEBUG
enabled which is observed during systemd boot process after recent
dma-debug changes:

DMA-API: e1000 0000:00:03.0: cacheline tracking EEXIST, overlapping mappings aren't supported
WARNING: CPU: 4 PID: 941 at kernel/dma/debug.c:596 add_dma_entry
CPU: 4 UID: 0 PID: 941 Comm: ip Not tainted 6.12.0+ #288
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:add_dma_entry kernel/dma/debug.c:596
Call Trace:
 <TASK>
debug_dma_map_page kernel/dma/debug.c:1236
dma_map_page_attrs kernel/dma/mapping.c:179
e1000_alloc_rx_buffers drivers/net/ethernet/intel/e1000/e1000_main.c:4616
...

Found by Linux Verification Center (linuxtesting.org).

Fixes: 9d4f645a1f ("dma-debug: store a phys_addr_t in struct dma_debug_entry")
Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
[hch: added a little helper to clean up the code]
Signed-off-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Fedor Pchelkin 2024-11-27 21:59:26 +03:00 committed by Christoph Hellwig
parent 22293c3373
commit aef7ee7649
1 changed files with 15 additions and 5 deletions
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20
kernel/dma/debug.c
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@ -1219,7 +1219,7 @@ void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
entry->dev = dev;
entry->type = dma_debug_single;
entry->paddr = page_to_phys(page);
entry->paddr = page_to_phys(page) + offset;
entry->dev_addr = dma_addr;
entry->size = size;
entry->direction = direction;
@ -1377,6 +1377,18 @@ void debug_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
}
}
static phys_addr_t virt_to_paddr(void *virt)
{
struct page *page;
if (is_vmalloc_addr(virt))
page = vmalloc_to_page(virt);
else
page = virt_to_page(virt);
return page_to_phys(page) + offset_in_page(virt);
}
void debug_dma_alloc_coherent(struct device *dev, size_t size,
dma_addr_t dma_addr, void *virt,
unsigned long attrs)
@ -1399,8 +1411,7 @@ void debug_dma_alloc_coherent(struct device *dev, size_t size,
entry->type = dma_debug_coherent;
entry->dev = dev;
entry->paddr = page_to_phys((is_vmalloc_addr(virt) ?
vmalloc_to_page(virt) : virt_to_page(virt)));
entry->paddr = virt_to_paddr(virt);
entry->size = size;
entry->dev_addr = dma_addr;
entry->direction = DMA_BIDIRECTIONAL;
@ -1423,8 +1434,7 @@ void debug_dma_free_coherent(struct device *dev, size_t size,
if (!is_vmalloc_addr(virt) && !virt_addr_valid(virt))
return;
ref.paddr = page_to_phys((is_vmalloc_addr(virt) ?
vmalloc_to_page(virt) : virt_to_page(virt)));
ref.paddr = virt_to_paddr(virt);
if (unlikely(dma_debug_disabled()))
return;