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SubjectRe: [PATCH] bitmap: Fix undefined shift in __bitmap_shift_left()
On Wed 22-10-14 14:43:51, Jan Kara wrote:
> It __bitmap_shift_left() is asked to shift by a multiple of
> BITS_PER_LONG, it will try to shift a long value by BITS_PER_LONG bits
> which is undefined. Change the function to take this into account.
>
> Coverity-id: 1192175
> CC: Rasmus Villemoes <linux@rasmusvillemoes.dk>
> CC: stable@vger.kernel.org
> Signed-off-by: Jan Kara <jack@suse.cz>
Oops, there's one more occurence of this. I'll send an updated patch.

Honza
> ---
> lib/bitmap.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/lib/bitmap.c b/lib/bitmap.c
> index cd250a2e14cb..02a8a439fcc7 100644
> --- a/lib/bitmap.c
> +++ b/lib/bitmap.c
> @@ -172,7 +172,9 @@ void __bitmap_shift_left(unsigned long *dst,
> 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;
> }
> --
> 1.8.1.4
>
--
Jan Kara <jack@suse.cz>
SUSE Labs, CR


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