mm: make vb_alloc() more foolproof
If someone calls vb_alloc() (or vm_map_ram() for that matter) to allocate 0 bytes (0 pages), get_order() returns BITS_PER_LONG - PAGE_CACHE_SHIFT and interesting stuff happens. So make debugging such problems easier and warn about 0-size allocation. [akpm@linux-foundation.org: use WARN_ON-return-value feature] Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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@ -904,6 +904,14 @@ static void *vb_alloc(unsigned long size, gfp_t gfp_mask)
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BUG_ON(size & ~PAGE_MASK);
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BUG_ON(size & ~PAGE_MASK);
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BUG_ON(size > PAGE_SIZE*VMAP_MAX_ALLOC);
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BUG_ON(size > PAGE_SIZE*VMAP_MAX_ALLOC);
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if (WARN_ON(size == 0)) {
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/*
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* Allocating 0 bytes isn't what caller wants since
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* get_order(0) returns funny result. Just warn and terminate
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* early.
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*/
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return NULL;
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}
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order = get_order(size);
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order = get_order(size);
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again:
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again:
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