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dma-debug: Ensure mappings are created and released with matching attributes

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The DMA API expects that callers use the same attributes when mapping
and unmapping. Add tracking to verify this and catch mismatches.

Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Reviewed-by: Samiullah Khawaja <skhawaja@google.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20260501-dma-attrs-debug-v2-6-8dbac75cd501@nvidia.com
This commit is contained in:
Leon Romanovsky
2026-05-01 09:35:10 +03:00
committed by Marek Szyprowski
parent c8411b1d1e
commit a34bd60bda
1 changed files with 23 additions and 0 deletions
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23
kernel/dma/debug.c
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@@ -1074,6 +1074,29 @@ static void check_unmap(struct dma_debug_entry *ref)
type2name[entry->type]);
}
/*
* This may be no bug in reality - but DMA API still expects
* that entry is unmapped with same attributes as it was mapped.
*
* DMA_ATTR_UNMAP_VALID lists the attributes that must be identical
* between map and unmap. Any attribute outside this set (e.g.
* DMA_ATTR_NO_WARN, DMA_ATTR_SKIP_CPU_SYNC) is allowed to differ.
*/
#define DMA_ATTR_UNMAP_VALID \
(DMA_ATTR_NO_KERNEL_MAPPING | DMA_ATTR_FORCE_CONTIGUOUS | \
DMA_ATTR_MMIO | DMA_ATTR_REQUIRE_COHERENT | DMA_ATTR_PRIVILEGED | \
DMA_ATTR_CC_SHARED)
if ((ref->attrs & DMA_ATTR_UNMAP_VALID) !=
(entry->attrs & DMA_ATTR_UNMAP_VALID)) {
err_printk(ref->dev, entry,
"device driver frees "
"DMA memory with different attributes "
"[device address=0x%016llx] [size=%llu bytes] "
"[mapped with 0x%lx] [unmapped with 0x%lx]\n",
ref->dev_addr, ref->size, entry->attrs, ref->attrs);
}
#undef DMA_ATTR_UNMAP_VALID
hash_bucket_del(entry);
put_hash_bucket(bucket, flags);