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| author | Jan Kara <jack@suse.cz> | 2014-10-29 14:50:44 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-10-29 16:33:14 -0700 |
| commit | ea5d05b34aca25c066e0699512d0ffbd8ee6ac3e (patch) | |
| tree | 279314a06c4f6211997b53caef834c866f957a6f | |
| parent | 5a6e7599d3f8000496068b12276492311efad5ea (diff) | |
| download | lwn-ea5d05b34aca25c066e0699512d0ffbd8ee6ac3e.tar.gz lwn-ea5d05b34aca25c066e0699512d0ffbd8ee6ac3e.zip | |
lib/bitmap.c: fix undefined shift in __bitmap_shift_{left|right}()
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 <jack@suse.cz>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | lib/bitmap.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/lib/bitmap.c b/lib/bitmap.c index cd250a2e14cb..b499ab6ada29 100644 --- a/lib/bitmap.c +++ b/lib/bitmap.c @@ -131,7 +131,9 @@ void __bitmap_shift_right(unsigned long *dst, 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 *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; } |