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XArray: Fix xas_pause for large multi-index entries 

commit c36d451ad3 upstream.

Inspired by the recent Coverity report, I looked for other places where
the offset wasn't being converted to an unsigned long before being
shifted, and I found one in xas_pause() when the entry being paused is
of order >32.

Fixes: b803b42823 ("xarray: Add XArray iterators")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
5.4-rM2-2.2.x-imx-squashed
Matthew Wilcox (Oracle) 2020-01-31 06:17:09 -05:00 committed by Greg Kroah-Hartman
parent a1ffc47f22
commit 8f4c8e92bd
2 changed files with 38 additions and 1 deletions
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37
lib/test_xarray.c
View File

@ -1156,6 +1156,42 @@ static noinline void check_find_entry(struct xarray *xa)
XA_BUG_ON(xa, !xa_empty(xa));
}
static noinline void check_pause(struct xarray *xa)
{
XA_STATE(xas, xa, 0);
void *entry;
unsigned int order;
unsigned long index = 1;
unsigned int count = 0;
for (order = 0; order < order_limit; order++) {
XA_BUG_ON(xa, xa_store_order(xa, index, order,
xa_mk_index(index), GFP_KERNEL));
index += 1UL << order;
}
rcu_read_lock();
xas_for_each(&xas, entry, ULONG_MAX) {
XA_BUG_ON(xa, entry != xa_mk_index(1UL << count));
count++;
}
rcu_read_unlock();
XA_BUG_ON(xa, count != order_limit);
count = 0;
xas_set(&xas, 0);
rcu_read_lock();
xas_for_each(&xas, entry, ULONG_MAX) {
XA_BUG_ON(xa, entry != xa_mk_index(1UL << count));
count++;
xas_pause(&xas);
}
rcu_read_unlock();
XA_BUG_ON(xa, count != order_limit);
xa_destroy(xa);
}
static noinline void check_move_tiny(struct xarray *xa)
{
XA_STATE(xas, xa, 0);
@ -1664,6 +1700,7 @@ static int xarray_checks(void)
check_xa_alloc();
check_find(&array);
check_find_entry(&array);
check_pause(&array);
check_account(&array);
check_destroy(&array);
check_move(&array);

2
lib/xarray.c
View File

@ -970,7 +970,7 @@ void xas_pause(struct xa_state *xas)
xas->xa_node = XAS_RESTART;
if (node) {
unsigned int offset = xas->xa_offset;
unsigned long offset = xas->xa_offset;
while (++offset < XA_CHUNK_SIZE) {
if (!xa_is_sibling(xa_entry(xas->xa, node, offset)))
break;