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authorToshi Kani <toshi.kani@hpe.com>2017-02-03 13:13:23 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2017-02-03 14:13:19 -0800
commita96dfddbcc04336bbed50dc2b24823e45e09e80c (patch)
tree0a6501e0d11cb978a46d8d3753dd449e57a97717 /drivers/base/memory.c
parentdeb88a2a19e85842d79ba96b05031739ec327ff4 (diff)
base/memory, hotplug: fix a kernel oops in show_valid_zones()
Reading a sysfs "memoryN/valid_zones" file leads to the following oops when the first page of a range is not backed by struct page. show_valid_zones() assumes that 'start_pfn' is always valid for page_zone(). BUG: unable to handle kernel paging request at ffffea017a000000 IP: show_valid_zones+0x6f/0x160 This issue may happen on x86-64 systems with 64GiB or more memory since their memory block size is bumped up to 2GiB. [1] An example of such systems is desribed below. 0x3240000000 is only aligned by 1GiB and this memory block starts from 0x3200000000, which is not backed by struct page. BIOS-e820: [mem 0x0000003240000000-0x000000603fffffff] usable Since test_pages_in_a_zone() already checks holes, fix this issue by extending this function to return 'valid_start' and 'valid_end' for a given range. show_valid_zones() then proceeds with the valid range. [1] 'Commit bdee237c0343 ("x86: mm: Use 2GB memory block size on large-memory x86-64 systems")' Link: http://lkml.kernel.org/r/20170127222149.30893-3-toshi.kani@hpe.com Signed-off-by: Toshi Kani <toshi.kani@hpe.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Zhang Zhen <zhenzhang.zhang@huawei.com> Cc: Reza Arbab <arbab@linux.vnet.ibm.com> Cc: David Rientjes <rientjes@google.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: <stable@vger.kernel.org> [4.4+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/base/memory.c')
-rw-r--r--drivers/base/memory.c12
1 files changed, 6 insertions, 6 deletions
diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index dacb6a8418aa..fa26ffd25fa6 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -389,33 +389,33 @@ static ssize_t show_valid_zones(struct device *dev,
{
struct memory_block *mem = to_memory_block(dev);
unsigned long start_pfn, end_pfn;
+ unsigned long valid_start, valid_end, valid_pages;
unsigned long nr_pages = PAGES_PER_SECTION * sections_per_block;
- struct page *first_page;
struct zone *zone;
int zone_shift = 0;
start_pfn = section_nr_to_pfn(mem->start_section_nr);
end_pfn = start_pfn + nr_pages;
- first_page = pfn_to_page(start_pfn);
/* The block contains more than one zone can not be offlined. */
- if (!test_pages_in_a_zone(start_pfn, end_pfn))
+ if (!test_pages_in_a_zone(start_pfn, end_pfn, &valid_start, &valid_end))
return sprintf(buf, "none\n");
- zone = page_zone(first_page);
+ zone = page_zone(pfn_to_page(valid_start));
+ valid_pages = valid_end - valid_start;
/* MMOP_ONLINE_KEEP */
sprintf(buf, "%s", zone->name);
/* MMOP_ONLINE_KERNEL */
- zone_can_shift(start_pfn, nr_pages, ZONE_NORMAL, &zone_shift);
+ zone_can_shift(valid_start, valid_pages, ZONE_NORMAL, &zone_shift);
if (zone_shift) {
strcat(buf, " ");
strcat(buf, (zone + zone_shift)->name);
}
/* MMOP_ONLINE_MOVABLE */
- zone_can_shift(start_pfn, nr_pages, ZONE_MOVABLE, &zone_shift);
+ zone_can_shift(valid_start, valid_pages, ZONE_MOVABLE, &zone_shift);
if (zone_shift) {
strcat(buf, " ");
strcat(buf, (zone + zone_shift)->name);