• Andrew Banman's avatar
    mm/memory_hotplug.c: check for missing sections in test_pages_in_a_zone() · 5f0f2887
    Andrew Banman authored
    test_pages_in_a_zone() does not account for the possibility of missing
    sections in the given pfn range.  pfn_valid_within always returns 1 when
    CONFIG_HOLES_IN_ZONE is not set, allowing invalid pfns from missing
    sections to pass the test, leading to a kernel oops.
    
    Wrap an additional pfn loop with PAGES_PER_SECTION granularity to check
    for missing sections before proceeding into the zone-check code.
    
    This also prevents a crash from offlining memory devices with missing
    sections.  Despite this, it may be a good idea to keep the related patch
    '[PATCH 3/3] drivers: memory: prohibit offlining of memory blocks with
    missing sections' because missing sections in a memory block may lead to
    other problems not covered by the scope of this fix.
    Signed-off-by: default avatarAndrew Banman <abanman@sgi.com>
    Acked-by: default avatarAlex Thorlton <athorlton@sgi.com>
    Cc: Russ Anderson <rja@sgi.com>
    Cc: Alex Thorlton <athorlton@sgi.com>
    Cc: Yinghai Lu <yinghai@kernel.org>
    Cc: Greg KH <greg@kroah.com>
    Cc: Seth Jennings <sjennings@variantweb.net>
    Cc: <stable@vger.kernel.org>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    5f0f2887
memory_hotplug.c 52.4 KB