Re: [PATCH] pack-bitmap: do not core dump
From: Junio C Hamano <hidden>
Date: 2016-06-15 23:00:47
"Kyle J. McKay" [off-list ref] writes:
So I was trying to use pack.writebitmaps=true and all I got was core dumps. The fix with a real subject line ;) is below. I think perhaps this should be picked up for the 2.0.0 release. (Patch is against master.)
Of course---a breakage in a new code may be less important than a regression fix in the sense that there is an option not to use the new feature, but an obvious fix to such a breakage is certainly very much welcomed during the -rc period. Thanks. I'll try not to forget until tomorrow's integration cycle (I just finished and pushed the results out for today), which will also give me a chance to wait for Peff's Ack ;-).
quoted hunk
--Kyle ---- >8 ---- Subject: [PATCH] ewah_bitmap.c: do not assume size_t and eword_t are the same size When buffer_grow changes the size of the buffer using realloc, it first computes and saves the rlw pointer's offset into the buffer using (uint8_t *) math before the realloc but then restores it using (eword_t *) math. In order to do this it's necessary to convert the (uint8_t *) offset into an (eword_t *) offset. It was doing this by dividing by the sizeof(size_t). Unfortunately sizeof(size_t) is not same as sizeof(eword_t) on all platforms. This causes illegal memory accesses and other bad things to happen when attempting to use bitmaps on those platforms. Fix this by dividing by the sizeof(eword_t) instead which will always be correct for all platforms. Signed-off-by: Kyle J. McKay <redacted> --- ewah/ewah_bitmap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)diff --git a/ewah/ewah_bitmap.c b/ewah/ewah_bitmap.c index 9ced2dad..fccb42b5 100644 --- a/ewah/ewah_bitmap.c +++ b/ewah/ewah_bitmap.c@@ -41,7 +41,7 @@ static inline void buffer_grow(struct ewah_bitmap *self, size_t new_size) self->alloc_size = new_size; self->buffer = ewah_realloc(self->buffer, self->alloc_size * sizeof(eword_t)); - self->rlw = self->buffer + (rlw_offset / sizeof(size_t)); + self->rlw = self->buffer + (rlw_offset / sizeof(eword_t)); } static inline void buffer_push(struct ewah_bitmap *self, eword_t value)