The patch titled
Subject: mm: page_alloc: fix CMA area initialisation when pageblock >
MAX_ORDER
has been removed from the -mm tree. Its filename was
mm-page_alloc-fix-cma-area-initialisation-when-pageblock-max_order.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Michal Nazarewicz <[email protected]>
Subject: mm: page_alloc: fix CMA area initialisation when pageblock > MAX_ORDER
With a kernel configured with ARM64_64K_PAGES && !TRANSPARENT_HUGEPAGE,
the following is triggered at early boot:
SMP: Total of 8 processors activated.
devtmpfs: initialized
Unable to handle kernel NULL pointer dereference at virtual address 00000008
pgd = fffffe0000050000
[00000008] *pgd=00000043fba00003, *pmd=00000043fba00003, *pte=00e0000078010407
Internal error: Oops: 96000006 [#1] SMP
Modules linked in:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.15.0-rc864k+ #44
task: fffffe03bc040000 ti: fffffe03bc080000 task.ti: fffffe03bc080000
PC is at __list_add+0x10/0xd4
LR is at free_one_page+0x270/0x638
...
Call trace:
[<fffffe00003ee970>] __list_add+0x10/0xd4
[<fffffe000019c478>] free_one_page+0x26c/0x638
[<fffffe000019c8c8>] __free_pages_ok.part.52+0x84/0xbc
[<fffffe000019d5e8>] __free_pages+0x74/0xbc
[<fffffe0000c01350>] init_cma_reserved_pageblock+0xe8/0x104
[<fffffe0000c24de0>] cma_init_reserved_areas+0x190/0x1e4
[<fffffe0000090418>] do_one_initcall+0xc4/0x154
[<fffffe0000bf0a50>] kernel_init_freeable+0x204/0x2a8
[<fffffe00007520a0>] kernel_init+0xc/0xd4
This happens because init_cma_reserved_pageblock() calls __free_one_page()
with pageblock_order as page order but it is bigger than MAX_ORDER. This
in turn causes accesses past zone->free_list[].
Fix the problem by changing init_cma_reserved_pageblock() such that it
splits pageblock into individual MAX_ORDER pages if pageblock is bigger
than a MAX_ORDER page.
In cases where !CONFIG_HUGETLB_PAGE_SIZE_VARIABLE, which is all
architectures expect for ia64, powerpc and tile at the moment, the
âpageblock_order > MAX_ORDERâ condition will be optimised out since
both sides of the operator are constants. In cases where pageblock size
is variable, the performance degradation should not be significant anyway
since init_cma_reserved_pageblock() is called only at boot time at most
MAX_CMA_AREAS times which by default is eight.
Signed-off-by: Michal Nazarewicz <[email protected]>
Reported-by: Mark Salter <[email protected]>
Tested-by: Mark Salter <[email protected]>
Tested-by: Christopher Covington <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: Marek Szyprowski <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: <[email protected]> [3.5+]
Signed-off-by: Andrew Morton <[email protected]>
---
mm/page_alloc.c | 16 ++++++++++++++--
1 file changed, 14 insertions(+), 2 deletions(-)
diff -puN
mm/page_alloc.c~mm-page_alloc-fix-cma-area-initialisation-when-pageblock-max_order
mm/page_alloc.c
---
a/mm/page_alloc.c~mm-page_alloc-fix-cma-area-initialisation-when-pageblock-max_order
+++ a/mm/page_alloc.c
@@ -816,9 +816,21 @@ void __init init_cma_reserved_pageblock(
set_page_count(p, 0);
} while (++p, --i);
- set_page_refcounted(page);
set_pageblock_migratetype(page, MIGRATE_CMA);
- __free_pages(page, pageblock_order);
+
+ if (pageblock_order >= MAX_ORDER) {
+ i = pageblock_nr_pages;
+ p = page;
+ do {
+ set_page_refcounted(p);
+ __free_pages(p, MAX_ORDER - 1);
+ p += MAX_ORDER_NR_PAGES;
+ } while (i -= MAX_ORDER_NR_PAGES);
+ } else {
+ set_page_refcounted(page);
+ __free_pages(page, pageblock_order);
+ }
+
adjust_managed_page_count(page, pageblock_nr_pages);
}
#endif
_
Patches currently in -mm which might be from [email protected] are
mm-page_alloc-simplify-drain_zone_pages-by-using-min.patch
dma-cma-separate-core-cma-management-codes-from-dma-apis.patch
dma-cma-support-alignment-constraint-on-cma-region.patch
dma-cma-support-arbitrary-bitmap-granularity.patch
dma-cma-support-arbitrary-bitmap-granularity-fix.patch
cma-generalize-cma-reserved-area-management-functionality.patch
ppc-kvm-cma-use-general-cma-reserved-area-management-framework.patch
mm-cma-clean-up-cma-allocation-error-path.patch
mm-cma-change-cma_declare_contiguous-to-obey-coding-convention.patch
mm-cma-clean-up-log-message.patch
mm-compactionc-isolate_freepages_block-small-tuneup.patch
include-kernelh-rewrite-min3-max3-and-clamp-using-min-and-max.patch
include-kernelh-rewrite-min3-max3-and-clamp-using-min-and-max-fix.patch
linux-next.patch
debugging-keep-track-of-page-owners.patch
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