This is a note to let you know that I've just added the patch titled
mm: page_alloc: fix CMA area initialisation when pageblock > MAX_ORDER
to the 3.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mm-page_alloc-fix-cma-area-initialisation-when-pageblock-max_order.patch
and it can be found in the queue-3.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From dc78327c0ea7da5186d8cbc1647bd6088c5c9fa5 Mon Sep 17 00:00:00 2001
From: Michal Nazarewicz <mina86@xxxxxxxxxx>
Date: Wed, 2 Jul 2014 15:22:35 -0700
Subject: mm: page_alloc: fix CMA area initialisation when pageblock > MAX_ORDER
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From: Michal Nazarewicz <mina86@xxxxxxxxxx>
commit dc78327c0ea7da5186d8cbc1647bd6088c5c9fa5 upstream.
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:
__list_add+0x10/0xd4
free_one_page+0x26c/0x638
__free_pages_ok.part.52+0x84/0xbc
__free_pages+0x74/0xbc
init_cma_reserved_pageblock+0xe8/0x104
cma_init_reserved_areas+0x190/0x1e4
do_one_initcall+0xc4/0x154
kernel_init_freeable+0x204/0x2a8
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
“pageblock_order > MAX_ORDER†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>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
mm/page_alloc.c | 16 ++++++++++++++--
1 file changed, 14 insertions(+), 2 deletions(-)
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -799,9 +799,21 @@ 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 stable-queue which might be from mina86@xxxxxxxxxx are
queue-3.14/tools-ffs-test-fix-header-values-endianess.patch
queue-3.14/usb-gadget-f_fs-fix-null-pointer-dereference-when-there-are-no-strings.patch
queue-3.14/usb-gadget-f_fs-resurect-usb_functionfs_descs_head-structure.patch
queue-3.14/mm-page_alloc-fix-cma-area-initialisation-when-pageblock-max_order.patch
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