The patch titled
Subject: mm/sparse.c: fix memory leak of sparsemap_buf in aliged memory
has been added to the -mm tree. Its filename is
mm-sparse-fix-memory-leak-of-sparsemap_buf-in-aliged-memory.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-sparse-fix-memory-leak-of-sparsemap_buf-in-aliged-memory.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-sparse-fix-memory-leak-of-sparsemap_buf-in-aliged-memory.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Lecopzer Chen <lecopzer.chen@xxxxxxxxxxxx>
Subject: mm/sparse.c: fix memory leak of sparsemap_buf in aliged memory
sparse_buffer_alloc(xsize) gets the size of memory from sparsemap_buf
after being aligned with the size. However, the size is at least
PAGE_ALIGN(sizeof(struct page) * PAGES_PER_SECTION) and usually larger
than PAGE_SIZE.
Also, sparse_buffer_fini() only frees memory between sparsemap_buf and
sparsemap_buf_end, since sparsemap_buf may be changed by PTR_ALIGN()
first, the aligned space before sparsemap_buf is wasted and no one will
touch it.
In our ARM32 platform (without SPARSEMEM_VMEMMAP)
Sparse_buffer_init
Reserve d359c000 - d3e9c000 (9M)
Sparse_buffer_alloc
Alloc d3a00000 - d3E80000 (4.5M)
Sparse_buffer_fini
Free d3e80000 - d3e9c000 (~=100k)
The reserved memory between d359c000 - d3a00000 (~=4.4M) is unfreed.
In ARM64 platform (with SPARSEMEM_VMEMMAP)
sparse_buffer_init
Reserve ffffffc07d623000 - ffffffc07f623000 (32M)
Sparse_buffer_alloc
Alloc ffffffc07d800000 - ffffffc07f600000 (30M)
Sparse_buffer_fini
Free ffffffc07f600000 - ffffffc07f623000 (140K)
The reserved memory between ffffffc07d623000 - ffffffc07d800000
(~=1.9M) is unfreed.
Let's explicit free redundant aligned memory.
Link: http://lkml.kernel.org/r/20190705114730.28534-1-lecopzer.chen@xxxxxxxxxxxx
Signed-off-by: Lecopzer Chen <lecopzer.chen@xxxxxxxxxxxx>
Signed-off-by: Mark-PK Tsai <Mark-PK.Tsai@xxxxxxxxxxxx>
Cc: YJ Chiang <yj.chiang@xxxxxxxxxxxx>
Cc: Lecopzer Chen <lecopzer.chen@xxxxxxxxxxxx>
Cc: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx>
Cc: Oscar Salvador <osalvador@xxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Mike Rapoport <rppt@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/sparse.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
--- a/mm/sparse.c~mm-sparse-fix-memory-leak-of-sparsemap_buf-in-aliged-memory
+++ a/mm/sparse.c
@@ -428,6 +428,12 @@ struct page __init *sparse_mem_map_popul
static void *sparsemap_buf __meminitdata;
static void *sparsemap_buf_end __meminitdata;
+static inline void __init sparse_buffer_free(unsigned long size)
+{
+ WARN_ON(!sparsemap_buf || size == 0);
+ memblock_free_early(__pa(sparsemap_buf), size);
+}
+
static void __init sparse_buffer_init(unsigned long size, int nid)
{
phys_addr_t addr = __pa(MAX_DMA_ADDRESS);
@@ -444,7 +450,7 @@ static void __init sparse_buffer_fini(vo
unsigned long size = sparsemap_buf_end - sparsemap_buf;
if (sparsemap_buf && size > 0)
- memblock_free_early(__pa(sparsemap_buf), size);
+ sparse_buffer_free(size);
sparsemap_buf = NULL;
}
@@ -456,8 +462,12 @@ void * __meminit sparse_buffer_alloc(uns
ptr = PTR_ALIGN(sparsemap_buf, size);
if (ptr + size > sparsemap_buf_end)
ptr = NULL;
- else
+ else {
+ /* Free redundant aligned space */
+ if ((unsigned long)(ptr - sparsemap_buf) > 0)
+ sparse_buffer_free((unsigned long)(ptr - sparsemap_buf));
sparsemap_buf = ptr + size;
+ }
}
return ptr;
}
_
Patches currently in -mm which might be from lecopzer.chen@xxxxxxxxxxxx are
mm-sparse-fix-memory-leak-of-sparsemap_buf-in-aliged-memory.patch
mm-sparse-fix-align-without-power-of-2-in-sparse_buffer_alloc.patch
