3.13.11-ckt13 -stable review patch. If anyone has any objections, please let me know.
------------------ From: Daniel Forrest <dan.forr...@ssec.wisc.edu> commit c4ea95d7cd08d9ffd7fa75e6c5e0332d596dd11e upstream. 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: ef0855d334e1 ("mm: mempolicy: turn vma_set_policy() into vma_dup_policy()") Signed-off-by: Daniel Forrest <dan.forr...@ssec.wisc.edu> Reviewed-by: Michal Hocko <mho...@suse.cz> Cc: Konstantin Khlebnikov <koc...@gmail.com> Cc: Andrea Arcangeli <aarca...@redhat.com> Cc: Rik van Riel <r...@redhat.com> Cc: Tim Hartrick <t...@edgecast.com> Cc: Hugh Dickins <hu...@google.com> Cc: Michel Lespinasse <wal...@google.com> Cc: Vlastimil Babka <vba...@suse.cz> Signed-off-by: Andrew Morton <a...@linux-foundation.org> Signed-off-by: Linus Torvalds <torva...@linux-foundation.org> Signed-off-by: Kamal Mostafa <ka...@canonical.com> --- mm/mmap.c | 10 +++++++--- mm/rmap.c | 6 ++++-- 2 files changed, 11 insertions(+), 5 deletions(-) diff --git a/mm/mmap.c b/mm/mmap.c index 32dbf6d..d407dcd 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -742,8 +742,11 @@ again: remove_next = 1 + (end > next->vm_end); * shrinking vma had, to cover any anon pages imported. */ if (exporter && exporter->anon_vma && !importer->anon_vma) { - if (anon_vma_clone(importer, exporter)) - return -ENOMEM; + int error; + + error = anon_vma_clone(importer, exporter); + if (error) + return error; importer->anon_vma = exporter->anon_vma; } } @@ -2414,7 +2417,8 @@ static int __split_vma(struct mm_struct * mm, struct vm_area_struct * vma, if (err) goto out_free_vma; - if (anon_vma_clone(new, vma)) + err = anon_vma_clone(new, vma); + if (err) goto out_free_mpol; if (new->vm_file) diff --git a/mm/rmap.c b/mm/rmap.c index cd6b576..ac0506d 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -274,6 +274,7 @@ int anon_vma_fork(struct vm_area_struct *vma, struct vm_area_struct *pvma) { struct anon_vma_chain *avc; struct anon_vma *anon_vma; + int error; /* Don't bother if the parent process has no anon_vma here. */ if (!pvma->anon_vma) @@ -283,8 +284,9 @@ int anon_vma_fork(struct vm_area_struct *vma, struct vm_area_struct *pvma) * First, attach the new VMA to the parent VMA's anon_vmas, * so rmap can find non-COWed pages in child processes. */ - if (anon_vma_clone(vma, pvma)) - return -ENOMEM; + error = anon_vma_clone(vma, pvma); + if (error) + return error; /* Then add our own anon_vma. */ anon_vma = anon_vma_alloc(); -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/