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hugetlb: fix resv_map leak in error path 

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>
Cc: <stable@vger.kernel.org>	[2.6.32+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Dave Hansen 2012-05-29 15:06:46 -07:00 committed by Linus Torvalds
parent 5c2b8a162b
commit c50ac05081
1 changed files with 22 additions and 6 deletions
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28
mm/hugetlb.c
View File

@ -2157,6 +2157,15 @@ 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);
@ -2173,7 +2182,7 @@ 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);
@ -2991,12 +3000,16 @@ 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 pages in the subpool for the mapping */
if (hugepage_subpool_get_pages(spool, chg))
return -ENOSPC;
if (hugepage_subpool_get_pages(spool, chg)) {
ret = -ENOSPC;
goto out_err;
}
/*
* Check enough hugepages are available for the reservation.
@ -3005,7 +3018,7 @@ int hugetlb_reserve_pages(struct inode *inode,
ret = hugetlb_acct_memory(h, chg);
if (ret < 0) {
hugepage_subpool_put_pages(spool, chg);
return ret;
goto out_err;
}
/*
@ -3022,6 +3035,9 @@ 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)