Commit fed33bd1 authored Oct 11, 2019 by Vladimir Sementsov-Ogievskiy Committed by Max Reitz Oct 28, 2019

hbitmap: handle set/reset with zero length



Passing zero length to these functions leads to unpredicted results.
Zero-length set/reset may occur in active-mirror, on zero-length write
(which is unlikely, but not guaranteed to never happen).

Let's just do nothing on zero-length request.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-id: 20191011090711.19940-2-vsementsov@virtuozzo.com
Reviewed-by: Max Reitz <mreitz@redhat.com>
Cc: qemu-stable@nongnu.org
Signed-off-by: Max Reitz <mreitz@redhat.com>

parent 767de537

util/hbitmap.c

+8 −0

Original line number	Diff line number	Diff line
		@@ -387,6 +387,10 @@ void hbitmap_set(HBitmap *hb, uint64_t start, uint64_t count)
		uint64_t first, n;
		uint64_t last = start + count - 1;

		if (count == 0) {
		return;
		}

		trace_hbitmap_set(hb, start, count,
		start >> hb->granularity, last >> hb->granularity);

		@@ -478,6 +482,10 @@ void hbitmap_reset(HBitmap *hb, uint64_t start, uint64_t count)
		uint64_t last = start + count - 1;
		uint64_t gran = 1ULL << hb->granularity;

		if (count == 0) {
		return;
		}

		assert(QEMU_IS_ALIGNED(start, gran));
		assert(QEMU_IS_ALIGNED(count, gran) \|\| (start + count == hb->orig_size));