From e12ed72e5c00dd3375b8bd107200e4d7e950276a Mon Sep 17 00:00:00 2001 From: Peter Lieven Date: Thu, 19 Jan 2017 17:43:50 +0100 Subject: [PATCH] bitmap: assert that start and nr are non negative commit e1123a3b introduced a data corruption regression in the iscsi driver because it passed -1 as nr to bitmap_set and bitmap_clear. Add an assertion to catch such flaws earlier. Suggested-by: Fam Zheng Reviewed-by: Fam Zheng Signed-off-by: Peter Lieven Message-Id: <1484844230-24490-1-git-send-email-pl@kamp.de> Signed-off-by: Paolo Bonzini --- util/bitmap.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/util/bitmap.c b/util/bitmap.c index 43ed011720..c1a84ca5e3 100644 --- a/util/bitmap.c +++ b/util/bitmap.c @@ -164,6 +164,8 @@ void bitmap_set(unsigned long *map, long start, long nr) int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG); unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start); + assert(start >= 0 && nr >= 0); + while (nr - bits_to_set >= 0) { *p |= mask_to_set; nr -= bits_to_set; @@ -184,6 +186,8 @@ void bitmap_set_atomic(unsigned long *map, long start, long nr) int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG); unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start); + assert(start >= 0 && nr >= 0); + /* First word */ if (nr - bits_to_set > 0) { atomic_or(p, mask_to_set); @@ -221,6 +225,8 @@ void bitmap_clear(unsigned long *map, long start, long nr) int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG); unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start); + assert(start >= 0 && nr >= 0); + while (nr - bits_to_clear >= 0) { *p &= ~mask_to_clear; nr -= bits_to_clear; @@ -243,6 +249,8 @@ bool bitmap_test_and_clear_atomic(unsigned long *map, long start, long nr) unsigned long dirty = 0; unsigned long old_bits; + assert(start >= 0 && nr >= 0); + /* First word */ if (nr - bits_to_clear > 0) { old_bits = atomic_fetch_and(p, ~mask_to_clear);