6.12-stable review patch. If anyone has any objections, please let me know.
------------------
From: Fedor Pchelkin pchelkin@ispras.ru
[ Upstream commit aef7ee7649e02f7fc0d2e5e532f352496976dcb1 ]
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: 9d4f645a1fd4 ("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 Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/dma/debug.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-)
diff --git a/kernel/dma/debug.c b/kernel/dma/debug.c index 0221023e1120d..39972e834e7a1 100644 --- a/kernel/dma/debug.c +++ b/kernel/dma/debug.c @@ -1224,7 +1224,7 @@ 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; @@ -1382,6 +1382,18 @@ 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) @@ -1404,8 +1416,7 @@ 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; @@ -1428,8 +1439,7 @@ 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;