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mm/cma: fix potential memory loss on cma_declare_contiguous_nid 

Suppose memblock_alloc_range_nid() with highmem_start succeeds when
cma_declare_contiguous_nid is called with !fixed on a 32-bit system with
PHYS_ADDR_T_64BIT enabled with memblock.bottom_up == false.

But the next trial to memblock_alloc_range_nid() to allocate in [SIZE_4G,
limits) nullifies former successfully allocated addr and it retries
memblock_alloc_ragne_nid().

In this situation, the first successfully allocated address area is lost.

Change the order of allocation (SIZE_4G, high_memory and base) and check
whether the allocated succeeded to prevent potential memory loss.

Link: https://lkml.kernel.org/r/20230118080523.44522-1-ppbuk5246@gmail.com
Signed-off-by: Levi Yun <ppbuk5246@gmail.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Levi Yun 2023-01-18 17:05:23 +09:00 committed by Andrew Morton
parent 5649d113ff
commit 148aa87e4f
1 changed files with 12 additions and 12 deletions
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24
mm/cma.c
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@ -321,18 +321,6 @@ int __init cma_declare_contiguous_nid(phys_addr_t base,
} else {
phys_addr_t addr = 0;
/*
* All pages in the reserved area must come from the same zone.
* If the requested region crosses the low/high memory boundary,
* try allocating from high memory first and fall back to low
* memory in case of failure.
*/
if (base < highmem_start && limit > highmem_start) {
addr = memblock_alloc_range_nid(size, alignment,
highmem_start, limit, nid, true);
limit = highmem_start;
}
/*
* If there is enough memory, try a bottom-up allocation first.
* It will place the new cma area close to the start of the node
@ -350,6 +338,18 @@ int __init cma_declare_contiguous_nid(phys_addr_t base,
}
#endif
/*
* All pages in the reserved area must come from the same zone.
* If the requested region crosses the low/high memory boundary,
* try allocating from high memory first and fall back to low
* memory in case of failure.
*/
if (!addr && base < highmem_start && limit > highmem_start) {
addr = memblock_alloc_range_nid(size, alignment,
highmem_start, limit, nid, true);
limit = highmem_start;
}
if (!addr) {
addr = memblock_alloc_range_nid(size, alignment, base,
limit, nid, true);