• Daniel Forrest's avatar
    mm: fix anon_vma_clone() error treatment · c4ea95d7
    Daniel Forrest authored
    Andrew Morton noticed that the error return from anon_vma_clone() was
    being dropped and replaced with -ENOMEM (which is not itself a bug
    because the only error return value from anon_vma_clone() is -ENOMEM).
    
    I did an audit of callers of anon_vma_clone() and discovered an actual
    bug where the error return was being lost.  In __split_vma(), between
    Linux 3.11 and 3.12 the code was changed so the err variable is used
    before the call to anon_vma_clone() and the default initial value of
    -ENOMEM is overwritten.  So a failure of anon_vma_clone() will return
    success since err at this point is now zero.
    
    Below is a patch which fixes this bug and also propagates the error
    return value from anon_vma_clone() in all cases.
    
    Fixes: ef0855d3 ("mm: mempolicy: turn vma_set_policy() into vma_dup_policy()")
    Signed-off-by: default avatarDaniel Forrest <dan.forrest@ssec.wisc.edu>
    Reviewed-by: default avatarMichal Hocko <mhocko@suse.cz>
    Cc: Konstantin Khlebnikov <koct9i@gmail.com>
    Cc: Andrea Arcangeli <aarcange@redhat.com>
    Cc: Rik van Riel <riel@redhat.com>
    Cc: Tim Hartrick <tim@edgecast.com>
    Cc: Hugh Dickins <hughd@google.com>
    Cc: Michel Lespinasse <walken@google.com>
    Cc: Vlastimil Babka <vbabka@suse.cz>
    Cc: <stable@vger.kernel.org>	[3.12+]
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    c4ea95d7
mmap.c 88.5 KB