Commit 22fed856 authored Jun 28, 2016 by Sunil Khatri Committed by Gerrit - the friendly Code Review server Jul 11, 2016

msm: kgsl: Fix the access to invalid pool



If a free page is not found in a particular pool, we
fall back to lower order pools. While doing so make
sure we dont do that when already in zero order pool.
For zero order(pool_idx = 0) pool, (pool_idx-1) value
becomes -1 that is invalid and compiler throws the error
that array subscript is below bounds.

This problem is exposed when we enable kernel config option
"CONFIG_ALLOC_BUFFERS_IN_4K_CHUNKS" which will force only
zero order pool and hence the index value calculation to -1.

Change-Id: I81e8a1e79cd974b7a13a9d23cb3d809464b6dcda
Signed-off-by: Sunil Khatri <sunilkh@codeaurora.org>

parent e99d73e0

drivers/gpu/msm/kgsl_pool.c

+5 −4

Original line number	Diff line number	Diff line
		@@ -331,9 +331,10 @@ int kgsl_pool_alloc_page(int page_size, struct page *pages,
		return -EINVAL;

		pool = _kgsl_get_pool_from_order(order);
		pool_idx = kgsl_pool_idx_lookup(order);
		if (pool == NULL)
		return -EINVAL;

		if (pool != NULL)
		pool_idx = kgsl_pool_idx_lookup(order);
		page = _kgsl_pool_get_page(pool);

		/* Allocate a new page if not allocated from pool */
		@@ -341,7 +342,7 @@ int kgsl_pool_alloc_page(int page_size, struct page *pages,
		gfp_t gfp_mask = kgsl_gfp_mask(order);

		/* Only allocate non-reserved memory for certain pools */
		if (!pool->allocation_allowed) {
		if (!pool->allocation_allowed && pool_idx > 0) {
		*page_size = PAGE_SIZE <<
		kgsl_pools[pool_idx-1].pool_order;
		align = ilog2(page_size);