• chenjie's avatar
    mm/madvise.c: fix madvise() infinite loop under special circumstances · 6ea8d958
    chenjie authored
    MADVISE_WILLNEED has always been a noop for DAX (formerly XIP) mappings.
    Unfortunately madvise_willneed() doesn't communicate this information
    properly to the generic madvise syscall implementation.  The calling
    convention is quite subtle there.  madvise_vma() is supposed to either
    return an error or update &prev otherwise the main loop will never
    advance to the next vma and it will keep looping for ever without a way
    to get out of the kernel.
    It seems this has been broken since introduction.  Nobody has noticed
    because nobody seems to be using MADVISE_WILLNEED on these DAX mappings.
    [mhocko@suse.com: rewrite changelog]
    Link: http://lkml.kernel.org/r/20171127115318.911-1-guoxuenan@huawei.com
    Fixes: fe77ba6f ("[PATCH] xip: madvice/fadvice: execute in place")
    Signed-off-by: default avatarchenjie <chenjie6@huawei.com>
    Signed-off-by: default avatarguoxuenan <guoxuenan@huawei.com>
    Acked-by: default avatarMichal Hocko <mhocko@suse.com>
    Cc: Minchan Kim <minchan@kernel.org>
    Cc: zhangyi (F) <yi.zhang@huawei.com>
    Cc: Miao Xie <miaoxie@huawei.com>
    Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
    Cc: Shaohua Li <shli@fb.com>
    Cc: Andrea Arcangeli <aarcange@redhat.com>
    Cc: Mel Gorman <mgorman@techsingularity.net>
    Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
    Cc: David Rientjes <rientjes@google.com>
    Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
    Cc: Rik van Riel <riel@redhat.com>
    Cc: Carsten Otte <cotte@de.ibm.com>
    Cc: Dan Williams <dan.j.williams@intel.com>
    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>
madvise.c 22.6 KB