diff options
| author | Toshi Kani <toshi.kani@hpe.com> | 2017-02-03 13:13:23 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-02-09 08:02:47 +0100 |
| commit | 87ebcc534d47dd924327daa651c36f876db76f72 (patch) | |
| tree | ebda72c898b17077e02cf4bcefdea506ffd878f9 /drivers | |
| parent | 374d06699537fa50aaf94bc2545e271015cb0105 (diff) | |
base/memory, hotplug: fix a kernel oops in show_valid_zones()
commit a96dfddbcc04336bbed50dc2b24823e45e09e80c upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/base/memory.c | 11 |
1 files changed, 5 insertions, 6 deletions
diff --git a/drivers/base/memory.c b/drivers/base/memory.c index 25425d3f2575..48c0a1d0dd3a 100644 --- a/drivers/base/memory.c +++ b/drivers/base/memory.c @@ -388,30 +388,29 @@ 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; unsigned long nr_pages = PAGES_PER_SECTION * sections_per_block; - struct page *first_page; struct zone *zone; 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)); if (zone_idx(zone) == ZONE_MOVABLE - 1) { /*The mem block is the last memoryblock of this zone.*/ - if (end_pfn == zone_end_pfn(zone)) + if (valid_end == zone_end_pfn(zone)) return sprintf(buf, "%s %s\n", zone->name, (zone + 1)->name); } if (zone_idx(zone) == ZONE_MOVABLE) { /*The mem block is the first memoryblock of ZONE_MOVABLE.*/ - if (start_pfn == zone->zone_start_pfn) + if (valid_start == zone->zone_start_pfn) return sprintf(buf, "%s %s\n", zone->name, (zone - 1)->name); } |