From: Ard Biesheuvel <a...@kernel.org>
free_highpages() iterates over the free memblock regions in high
memory, and marks each page as available for the memory management
system.
Until commit cddb5ddf2b76 ("arm, xtensa: simplify initialization of
high memory pages") it rounded beginning of each region upwards and end of
each region downwards.
However, after that commit free_highmem() rounds the beginning and end of
each region downwards, and we may end up freeing a page that is
memblock_reserve()d, resulting in memory corruption.
Restore the original rounding of the region boundaries to avoid freeing
reserved pages.
Fixes: cddb5ddf2b76 ("arm, xtensa: simplify initialization of high memory
pages")
Link: https://lore.kernel.org/r/20201029110334.4118-1-a...@kernel.org/
Signed-off-by: Ard Biesheuvel <a...@kernel.org>
Co-developed-by: Mike Rapoport <r...@linux.ibm.com>
Signed-off-by: Mike Rapoport <r...@linux.ibm.com>
---
Max, Russell,
Please let me know how do you prefer to take it upstream.
If needed this can go via memblock tree.
v2: fix words order in the commit message
arch/arm/mm/init.c | 4 ++--
arch/xtensa/mm/init.c | 4 ++--
2 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
index d57112a276f5..c23dbf8bebee 100644
--- a/arch/arm/mm/init.c
+++ b/arch/arm/mm/init.c
@@ -354,8 +354,8 @@ static void __init free_highpages(void)
/* set highmem page free */
for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE,
&range_start, &range_end, NULL) {
- unsigned long start = PHYS_PFN(range_start);
- unsigned long end = PHYS_PFN(range_end);
+ unsigned long start = PFN_UP(range_start);
+ unsigned long end = PFN_DOWN(range_end);
/* Ignore complete lowmem entries */
if (end <= max_low)
diff --git a/arch/xtensa/mm/init.c b/arch/xtensa/mm/init.c
index c6fc83efee0c..8731b7ad9308 100644
--- a/arch/xtensa/mm/init.c
+++ b/arch/xtensa/mm/init.c
@@ -89,8 +89,8 @@ static void __init free_highpages(void)
/* set highmem page free */
for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE,
&range_start, &range_end, NULL) {
- unsigned long start = PHYS_PFN(range_start);
- unsigned long end = PHYS_PFN(range_end);
+ unsigned long start = PFN_UP(range_start);
+ unsigned long end = PFN_DOWN(range_end);
/* Ignore complete lowmem entries */
if (end <= max_low)
--
2.28.0
