mm/cma: fix potential memory loss on cma_declare_contiguous_nid
authorLevi Yun <ppbuk5246@gmail.com>
Wed, 18 Jan 2023 08:05:23 +0000 (17:05 +0900)
committerAndrew Morton <akpm@linux-foundation.org>
Fri, 3 Feb 2023 06:33:24 +0000 (22:33 -0800)
commit148aa87e4f631e98d926d006604116fd2b2f3a93
tree03aaaf5d8bb58ba5f6e6a008a0c15fb4f81bd7bf
parent5649d113ffce9f532a9ecc5ab96a93e02efbf283
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>
mm/cma.c