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authorJan Kara <jack@suse.cz>2014-10-29 14:50:44 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-11-14 09:00:08 -0800
commit3e3fca71dd27993dff6591188c79ff26a3a55417 (patch)
treeea69c6970e07551c46a27a0cbca0315af5eaefa4
parentc65fabeffc5e5736465f89f1255c1953c9f60a9d (diff)
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lib/bitmap.c: fix undefined shift in __bitmap_shift_{left|right}()
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 <jack@suse.cz> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--lib/bitmap.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/lib/bitmap.c b/lib/bitmap.c
index 06f7e4fe8d2d..e5c4ebe586ba 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;
}