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dmapool: make DMAPOOL_DEBUG detect corruption of free marker

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This can help to catch the case where hardware is writing after dma free.

[akpm@linux-foundation.org: tidy code, fix comment, use sizeof(page->offset), use pr_err()]
Signed-off-by: Matthieu Castet <matthieu.castet@parrot.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Matthieu CASTET 2012-12-11 16:01:31 -08:00 committed by Linus Torvalds
parent 9ff4868e30
commit 5de55b265a
1 changed files with 24 additions and 0 deletions
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24
mm/dmapool.c
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@ -332,6 +332,30 @@ void *dma_pool_alloc(struct dma_pool *pool, gfp_t mem_flags,
retval = offset + page->vaddr;
*handle = offset + page->dma;
#ifdef DMAPOOL_DEBUG
{
int i;
u8 *data = retval;
/* page->offset is stored in first 4 bytes */
for (i = sizeof(page->offset); i < pool->size; i++) {
if (data[i] == POOL_POISON_FREED)
continue;
if (pool->dev)
dev_err(pool->dev,
"dma_pool_alloc %s, %p (corruped)\n",
pool->name, retval);
else
pr_err("dma_pool_alloc %s, %p (corruped)\n",
pool->name, retval);
/*
* Dump the first 4 bytes even if they are not
* POOL_POISON_FREED
*/
print_hex_dump(KERN_ERR, "", DUMP_PREFIX_OFFSET, 16, 1,
data, pool->size, 1);
break;
}
}
memset(retval, POOL_POISON_ALLOCATED, pool->size);
#endif
spin_unlock_irqrestore(&pool->lock, flags);