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Commit ea5d05b3 authored by Jan Kara's avatar Jan Kara Committed by Linus Torvalds
Browse files

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: default avatarJan Kara <jack@suse.cz>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 5a6e7599

lib/bitmap.c

+6 −2
Original line number Diff line number Diff line
@@ -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;

	}