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authorMatthew Wilcox <willy@infradead.org>2018-11-01 16:55:19 -0400
committerMatthew Wilcox <willy@infradead.org>2018-11-05 14:56:46 -0500
commit8229706e03e4147f3e22d1de0d30630cde6d18a9 (patch)
tree1994f5ff08f7b5c459eba5e26c868ee182d2392a /lib
parent651022382c7f8da46cb4872a545ee1da6d097d2a (diff)
XArray: Fix xa_for_each with a single element at 0
The following sequence of calls would result in an infinite loop in xa_find_after(): xa_store(xa, 0, x, GFP_KERNEL); index = 0; xa_for_each(xa, entry, index, ULONG_MAX, XA_PRESENT) { } xa_find_after() was confusing the situation where we found no entry in the tree with finding a multiorder entry, so it would look for the successor entry forever. Just check for this case explicitly. Includes a few new checks in the test suite to be sure this doesn't reappear. Signed-off-by: Matthew Wilcox <willy@infradead.org>
Diffstat (limited to 'lib')
-rw-r--r--lib/test_xarray.c30
-rw-r--r--lib/xarray.c2
2 files changed, 31 insertions, 1 deletions
diff --git a/lib/test_xarray.c b/lib/test_xarray.c
index aa47754150ce..126127658b49 100644
--- a/lib/test_xarray.c
+++ b/lib/test_xarray.c
@@ -702,7 +702,7 @@ static noinline void check_multi_find_2(struct xarray *xa)
}
}
-static noinline void check_find(struct xarray *xa)
+static noinline void check_find_1(struct xarray *xa)
{
unsigned long i, j, k;
@@ -748,6 +748,34 @@ static noinline void check_find(struct xarray *xa)
XA_BUG_ON(xa, xa_get_mark(xa, i, XA_MARK_0));
}
XA_BUG_ON(xa, !xa_empty(xa));
+}
+
+static noinline void check_find_2(struct xarray *xa)
+{
+ void *entry;
+ unsigned long i, j, index = 0;
+
+ xa_for_each(xa, entry, index, ULONG_MAX, XA_PRESENT) {
+ XA_BUG_ON(xa, true);
+ }
+
+ for (i = 0; i < 1024; i++) {
+ xa_store_index(xa, index, GFP_KERNEL);
+ j = 0;
+ index = 0;
+ xa_for_each(xa, entry, index, ULONG_MAX, XA_PRESENT) {
+ XA_BUG_ON(xa, xa_mk_value(index) != entry);
+ XA_BUG_ON(xa, index != j++);
+ }
+ }
+
+ xa_destroy(xa);
+}
+
+static noinline void check_find(struct xarray *xa)
+{
+ check_find_1(xa);
+ check_find_2(xa);
check_multi_find(xa);
check_multi_find_2(xa);
}
diff --git a/lib/xarray.c b/lib/xarray.c
index 8b176f009c08..c991ff4523ef 100644
--- a/lib/xarray.c
+++ b/lib/xarray.c
@@ -1829,6 +1829,8 @@ void *xa_find_after(struct xarray *xa, unsigned long *indexp,
entry = xas_find_marked(&xas, max, filter);
else
entry = xas_find(&xas, max);
+ if (xas.xa_node == XAS_BOUNDS)
+ break;
if (xas.xa_shift) {
if (xas.xa_index & ((1UL << xas.xa_shift) - 1))
continue;