3.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jan Kara <[email protected]>

commit ea5d05b34aca25c066e0699512d0ffbd8ee6ac3e upstream.

If __bitmap_shift_left() or __bitmap_shift_right() are asked to shift by
a multiple of BITS_PER_LONG, they will try to shift a long value by
BITS_PER_LONG bits which is undefined.  Change the functions to avoid
the undefined shift.

Coverity id: 1192175
Coverity id: 1192174
Signed-off-by: Jan Kara <[email protected]>
Cc: Rasmus Villemoes <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

---
 lib/bitmap.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -131,7 +131,9 @@ void __bitmap_shift_right(unsigned long
                lower = src[off + k];
                if (left && off + k == lim - 1)
                        lower &= mask;
-               dst[k] = upper << (BITS_PER_LONG - rem) | lower >> rem;
+               dst[k] = lower >> rem;
+               if (rem)
+                       dst[k] |= upper << (BITS_PER_LONG - rem);
                if (left && k == lim - 1)
                        dst[k] &= mask;
        }
@@ -172,7 +174,9 @@ void __bitmap_shift_left(unsigned long *
                upper = src[k];
                if (left && k == lim - 1)
                        upper &= (1UL << left) - 1;
-               dst[k + off] = lower  >> (BITS_PER_LONG - rem) | upper << rem;
+               dst[k + off] = upper << rem;
+               if (rem)
+                       dst[k + off] |= lower >> (BITS_PER_LONG - rem);
                if (left && k + off == lim - 1)
                        dst[k + off] &= (1UL << left) - 1;
        }


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Reply via email to