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 <mina86@xxxxxxxxxx>
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
â??pageblock_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 <mina86@xxxxxxxxxx>
Reported-by: Mark Salter <msalter@xxxxxxxxxx>
Tested-by: Mark Salter <msalter@xxxxxxxxxx>
Tested-by: Christopher Covington <cov@xxxxxxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> [3.5+]
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
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 mina86@xxxxxxxxxx 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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