Commit 84c34df1 authored Oct 13, 2020 by Matthew Wilcox (Oracle)

XArray: Fix xas_create_range for ranges above 4 billion

The 'sibs' variable would be shifted as a 32-bit integer, so if 'shift'
is more than 32, this is undefined behaviour. In practice, this doesn't
happen because the page cache is the only user and nobody uses 16TB pages.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

parent f78b8250

lib/xarray.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -703,7 +703,7 @@ void xas_create_range(struct xa_state *xas)
		unsigned char shift = xas->xa_shift;
		unsigned char sibs = xas->xa_sibs;

		xas->xa_index \|= ((sibs + 1) << shift) - 1;
		xas->xa_index \|= ((sibs + 1UL) << shift) - 1;
		if (xas_is_node(xas) && xas->xa_node->shift == xas->xa_shift)
		xas->xa_offset \|= sibs;
		xas->xa_shift = 0;

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