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>
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parent
5c2b8a162b
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c50ac05081
28
mm/hugetlb.c
28
mm/hugetlb.c
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@ -2157,6 +2157,15 @@ static void hugetlb_vm_op_open(struct vm_area_struct *vma)
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kref_get(&reservations->refs);
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kref_get(&reservations->refs);
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}
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}
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static void resv_map_put(struct vm_area_struct *vma)
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{
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struct resv_map *reservations = vma_resv_map(vma);
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if (!reservations)
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return;
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kref_put(&reservations->refs, resv_map_release);
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}
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static void hugetlb_vm_op_close(struct vm_area_struct *vma)
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static void hugetlb_vm_op_close(struct vm_area_struct *vma)
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{
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{
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struct hstate *h = hstate_vma(vma);
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struct hstate *h = hstate_vma(vma);
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@ -2173,7 +2182,7 @@ static void hugetlb_vm_op_close(struct vm_area_struct *vma)
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reserve = (end - start) -
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reserve = (end - start) -
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region_count(&reservations->regions, start, end);
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region_count(&reservations->regions, start, end);
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kref_put(&reservations->refs, resv_map_release);
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resv_map_put(vma);
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if (reserve) {
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if (reserve) {
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hugetlb_acct_memory(h, -reserve);
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hugetlb_acct_memory(h, -reserve);
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@ -2991,12 +3000,16 @@ int hugetlb_reserve_pages(struct inode *inode,
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set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
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set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
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}
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}
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if (chg < 0)
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if (chg < 0) {
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return chg;
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ret = chg;
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goto out_err;
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}
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/* There must be enough pages in the subpool for the mapping */
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/* There must be enough pages in the subpool for the mapping */
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if (hugepage_subpool_get_pages(spool, chg))
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if (hugepage_subpool_get_pages(spool, chg)) {
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return -ENOSPC;
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ret = -ENOSPC;
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goto out_err;
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}
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/*
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/*
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* Check enough hugepages are available for the reservation.
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* Check enough hugepages are available for the reservation.
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@ -3005,7 +3018,7 @@ int hugetlb_reserve_pages(struct inode *inode,
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ret = hugetlb_acct_memory(h, chg);
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ret = hugetlb_acct_memory(h, chg);
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if (ret < 0) {
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if (ret < 0) {
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hugepage_subpool_put_pages(spool, chg);
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hugepage_subpool_put_pages(spool, chg);
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return ret;
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goto out_err;
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}
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}
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/*
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/*
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@ -3022,6 +3035,9 @@ int hugetlb_reserve_pages(struct inode *inode,
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if (!vma || vma->vm_flags & VM_MAYSHARE)
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if (!vma || vma->vm_flags & VM_MAYSHARE)
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region_add(&inode->i_mapping->private_list, from, to);
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region_add(&inode->i_mapping->private_list, from, to);
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return 0;
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return 0;
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out_err:
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resv_map_put(vma);
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return ret;
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}
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}
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void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed)
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void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed)
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