Messages in this thread Patch in this message | | | Date | Thu, 14 Jun 2012 16:57:04 -0700 | From | Greg KH <> | Subject | [ 20/20] hugetlb: fix resv_map leak in error path |
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3.0-stable review patch. If anyone has any objections, please let me know.
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From: Dave Hansen <dave@linux.vnet.ibm.com>
commit c50ac050811d6485616a193eb0f37bfbd191cc89 and 4523e1458566a0e8ecfaff90f380dd23acc44d27 upstream.
When called for anonymous (non-shared) mappings, hugetlb_reserve_pages() does a resv_map_alloc(). It depends on code in hugetlbfs's vm_ops->close() to release that allocation.
However, in the mmap() failure path, we do a plain unmap_region() without the remove_vma() which actually calls vm_ops->close().
This is a decent fix. This leak could get reintroduced if new code (say, after hugetlb_reserve_pages() in hugetlbfs_file_mmap()) decides to return an error. But, I think it would have to unroll the reservation anyway.
Christoph's test case:
http://marc.info/?l=linux-mm&m=133728900729735
This patch applies to 3.4 and later. A version for earlier kernels is at https://lkml.org/lkml/2012/5/22/418.
Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reported-by: Christoph Lameter <cl@linux.com> Tested-by: Christoph Lameter <cl@linux.com> Cc: Andrea Arcangeli <aarcange@redhat.com> 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>
--- mm/hugetlb.c | 29 +++++++++++++++++++++++------ 1 file changed, 23 insertions(+), 6 deletions(-)
--- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -2060,6 +2060,15 @@ static void hugetlb_vm_op_open(struct vm kref_get(&reservations->refs); } +static void resv_map_put(struct vm_area_struct *vma) +{ + struct resv_map *reservations = vma_resv_map(vma); + + if (!reservations) + return; + kref_put(&reservations->refs, resv_map_release); +} + static void hugetlb_vm_op_close(struct vm_area_struct *vma) { struct hstate *h = hstate_vma(vma); @@ -2075,7 +2084,7 @@ static void hugetlb_vm_op_close(struct v reserve = (end - start) - region_count(&reservations->regions, start, end); - kref_put(&reservations->refs, resv_map_release); + resv_map_put(vma); if (reserve) { hugetlb_acct_memory(h, -reserve); @@ -2877,12 +2886,16 @@ int hugetlb_reserve_pages(struct inode * set_vma_resv_flags(vma, HPAGE_RESV_OWNER); } - if (chg < 0) - return chg; + if (chg < 0) { + ret = chg; + goto out_err; + } /* There must be enough filesystem quota for the mapping */ - if (hugetlb_get_quota(inode->i_mapping, chg)) - return -ENOSPC; + if (hugetlb_get_quota(inode->i_mapping, chg)) { + ret = -ENOSPC; + goto out_err; + } /* * Check enough hugepages are available for the reservation. @@ -2891,7 +2904,7 @@ int hugetlb_reserve_pages(struct inode * ret = hugetlb_acct_memory(h, chg); if (ret < 0) { hugetlb_put_quota(inode->i_mapping, chg); - return ret; + goto out_err; } /* @@ -2908,6 +2921,10 @@ int hugetlb_reserve_pages(struct inode * if (!vma || vma->vm_flags & VM_MAYSHARE) region_add(&inode->i_mapping->private_list, from, to); return 0; +out_err: + if (vma) + resv_map_put(vma); + return ret; } void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed)
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