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authorMatthew Wilcox (Oracle) <willy@infradead.org>2020-01-17 17:45:12 -0500
committerMatthew Wilcox (Oracle) <willy@infradead.org>2020-01-17 22:32:24 -0500
commit430f24f94c8a174d411a550d7b5529301922e67a (patch)
tree7a23f31ee6f3bca6a09e1ce0c23fa62d4e65c5e1 /lib/test_xarray.c
parent82a958497dc9120e0e8043da82273baedd255aaf (diff)
downloadlinux-430f24f94c8a174d411a550d7b5529301922e67a.tar.gz
XArray: Fix infinite loop with entry at ULONG_MAX
If there is an entry at ULONG_MAX, xa_for_each() will overflow the
'index + 1' in xa_find_after() and wrap around to 0.  Catch this case
and terminate the loop by returning NULL.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: stable@vger.kernel.org
Diffstat (limited to 'lib/test_xarray.c')
-rw-r--r--lib/test_xarray.c17
1 files changed, 17 insertions, 0 deletions
diff --git a/lib/test_xarray.c b/lib/test_xarray.c
index c477f22a95cd..90584c63ca39 100644
--- a/lib/test_xarray.c
+++ b/lib/test_xarray.c
@@ -1046,11 +1046,28 @@ static noinline void check_find_3(struct xarray *xa)
 	xa_destroy(xa);
 }
 
+static noinline void check_find_4(struct xarray *xa)
+{
+	unsigned long index = 0;
+	void *entry;
+
+	xa_store_index(xa, ULONG_MAX, GFP_KERNEL);
+
+	entry = xa_find_after(xa, &index, ULONG_MAX, XA_PRESENT);
+	XA_BUG_ON(xa, entry != xa_mk_index(ULONG_MAX));
+
+	entry = xa_find_after(xa, &index, ULONG_MAX, XA_PRESENT);
+	XA_BUG_ON(xa, entry);
+
+	xa_erase_index(xa, ULONG_MAX);
+}
+
 static noinline void check_find(struct xarray *xa)
 {
 	check_find_1(xa);
 	check_find_2(xa);
 	check_find_3(xa);
+	check_find_4(xa);
 	check_multi_find(xa);
 	check_multi_find_2(xa);
 }