dmapool: make DMAPOOL_DEBUG detect corruption of free marker
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>
diff --git a/mm/dmapool.c b/mm/dmapool.c
index da1b0f0..c69781e 100644
--- a/mm/dmapool.c
+++ b/mm/dmapool.c
@@ -332,6 +332,30 @@
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);
