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| author | Matthieu CASTET <matthieu.castet@parrot.com> | 2012-12-11 16:01:31 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-12-11 17:22:24 -0800 |
| commit | 5de55b265a13bc263c823bbe05d87d2c5e785f6f (patch) | |
| tree | 69082ec836d553c98b99e6a0f3aebe2649b4fad2 /mm/dmapool.c | |
| parent | 9ff4868e3051d9128a24dd330bed32011a11421d (diff) | |
| download | lwn-5de55b265a13bc263c823bbe05d87d2c5e785f6f.tar.gz lwn-5de55b265a13bc263c823bbe05d87d2c5e785f6f.zip | |
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>
Diffstat (limited to 'mm/dmapool.c')
| -rw-r--r-- | mm/dmapool.c | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/mm/dmapool.c b/mm/dmapool.c index da1b0f0b8709..c69781e97cf9 100644 --- a/mm/dmapool.c +++ b/mm/dmapool.c @@ -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); |