Commit 59749e6c authored by Johannes Weiner's avatar Johannes Weiner Committed by Linus Torvalds

mm: khugepaged: fix radix tree node leak in shmem collapse error path

The radix tree counts valid entries in each tree node.  Entries stored
in the tree cannot be removed by simpling storing NULL in the slot or
the internal counters will be off and the node never gets freed again.

When collapsing a shmem page fails, restore the holes that were filled
with radix_tree_insert() with a proper radix tree deletion.

Fixes: f3f0e1d2 ("khugepaged: add support of collapse for tmpfs/shmem pages")
Link: http://lkml.kernel.org/r/20161117191138.22769-3-hannes@cmpxchg.orgSigned-off-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Reported-by: default avatarJan Kara <jack@suse.cz>
Acked-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox <mawilcox@linuxonhyperv.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 91a45f71
...@@ -1525,9 +1525,11 @@ static void collapse_shmem(struct mm_struct *mm, ...@@ -1525,9 +1525,11 @@ static void collapse_shmem(struct mm_struct *mm,
if (!page || iter.index < page->index) { if (!page || iter.index < page->index) {
if (!nr_none) if (!nr_none)
break; break;
/* Put holes back where they were */
radix_tree_replace_slot(slot, NULL);
nr_none--; nr_none--;
/* Put holes back where they were */
radix_tree_delete(&mapping->page_tree,
iter.index);
slot = radix_tree_iter_next(&iter);
continue; continue;
} }
......
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