[ 082/102] s390/bitops: fix find_next_bit_left

From: Greg Kroah-Hartman
Date: Thu Aug 08 2013 - 21:59:37 EST


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

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

From: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>

commit 3b0040a47ad63f7147e9e7d2febb61a3b564bb90 upstream.

The find_next_bit_left function is broken if used with an offset which
is not a multiple of 64. The shift to mask the bits of a 64-bit word
not to search is in the wrong direction, the result can be either a
bit found smaller than the offset or failure to find a set bit.

Signed-off-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
arch/s390/include/asm/bitops.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/s390/include/asm/bitops.h
+++ b/arch/s390/include/asm/bitops.h
@@ -693,7 +693,7 @@ static inline int find_next_bit_left(con
size -= offset;
p = addr + offset / BITS_PER_LONG;
if (bit) {
- set = __flo_word(0, *p & (~0UL << bit));
+ set = __flo_word(0, *p & (~0UL >> bit));
if (set >= size)
return size + offset;
if (set < BITS_PER_LONG)


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