From: Dave Hansen <dave@xxxxxxxxxxxxxxxxxx>
-------------------
This is a commit scheduled for the next v2.6.34 longterm release.
http://git.kernel.org/?p=linux/kernel/git/paulg/longterm-queue-2.6.34.git
If you see a problem with using this for longterm, please comment.
-------------------
commit c50ac050811d6485616a193eb0f37bfbd191cc89 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@xxxxxxxxxxxxxxxxxx>
Acked-by: Mel Gorman <mel@xxxxxxxxx>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
Reported-by: Christoph Lameter <cl@xxxxxxxxx>
Tested-by: Christoph Lameter <cl@xxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
---
mm/hugetlb.c | 28 ++++++++++++++++++++++------
1 file changed, 22 insertions(+), 6 deletions(-)
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index ca9ce49d71e3..f7b80540ba95 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2030,6 +2030,15 @@ static void hugetlb_vm_op_open(struct vm_area_struct *vma)
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);
@@ -2045,7 +2054,7 @@ static void hugetlb_vm_op_close(struct vm_area_struct *vma)
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);
@@ -2744,12 +2753,16 @@ int hugetlb_reserve_pages(struct inode *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.
@@ -2758,7 +2771,7 @@ int hugetlb_reserve_pages(struct inode *inode,
ret = hugetlb_acct_memory(h, chg);
if (ret < 0) {
hugetlb_put_quota(inode->i_mapping, chg);
- return ret;
+ goto out_err;
}
/*
@@ -2775,6 +2788,9 @@ int hugetlb_reserve_pages(struct inode *inode,
if (!vma || vma->vm_flags & VM_MAYSHARE)
region_add(&inode->i_mapping->private_list, from, to);
return 0;
+out_err:
+ resv_map_put(vma);
+ return ret;
}
void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed)
--
1.8.5.2
--
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