diff options
authorMichal Nazarewicz <mina86@mina86.com>2014-07-02 15:22:35 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2014-07-03 09:21:53 -0700
commitdc78327c0ea7da5186d8cbc1647bd6088c5c9fa5 (patch)
parentd92a333a65a17b8638a0980df4bedf8a262b12f3 (diff)
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: __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@mina86.com> Reported-by: Mark Salter <msalter@redhat.com> Tested-by: Mark Salter <msalter@redhat.com> Tested-by: Christopher Covington <cov@codeaurora.org> Cc: Mel Gorman <mgorman@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: <stable@vger.kernel.org> [3.5+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 files changed, 14 insertions, 2 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 20d17f8266fe..0ea758b898fd 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -816,9 +816,21 @@ void __init init_cma_reserved_pageblock(struct page *page)
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);
+ } while (i -= MAX_ORDER_NR_PAGES);
+ } else {
+ set_page_refcounted(page);
+ __free_pages(page, pageblock_order);
+ }
adjust_managed_page_count(page, pageblock_nr_pages);