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[79.181.91.42]) by smtp.gmail.com with ESMTPSA id 42sm26348304qtm.27.2019.07.25.04.59.19 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Thu, 25 Jul 2019 04:59:20 -0700 (PDT) Date: Thu, 25 Jul 2019 07:59:17 -0400 From: "Michael S. Tsirkin" To: qemu-devel@nongnu.org Message-ID: <20190725115914.26983-1-mst@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Mailer: git-send-email 2.22.0.678.g13338e74b8 X-Mutt-Fcc: =sent X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.85.160.195 Subject: [Qemu-devel] [PATCH] virtio-balloon: free pbp more aggressively X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: qemu-stable@nongnu.org, David Hildenbrand Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Previous patches switched to a temporary pbp but that does not go far enough: after device uses a buffer, guest is free to reuse it, so tracking the page and freeing it later is wrong. Free and reset the pbp after we push each element. Fixes: ed48c59875b6 ("virtio-balloon: Safely handle BALLOON_PAGE_SIZE < host page size") Cc: qemu-stable@nongnu.org #v4.0.0 Cc: David Hildenbrand Signed-off-by: Michael S. Tsirkin --- hw/virtio/virtio-balloon.c | 18 ++++++++---------- 1 file changed, 8 insertions(+), 10 deletions(-) diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c index fe9664e42c..460a702463 100644 --- a/hw/virtio/virtio-balloon.c +++ b/hw/virtio/virtio-balloon.c @@ -39,13 +39,14 @@ typedef struct PartiallyBalloonedPage { unsigned long *bitmap; } PartiallyBalloonedPage; -static void virtio_balloon_pbp_free(PartiallyBalloonedPage *pbp) +static void virtio_balloon_pbp_free(PartiallyBalloonedPage **pbp) { - if (!pbp) { + if (!*pbp) { return; } - g_free(pbp->bitmap); - g_free(pbp); + g_free(*pbp->bitmap); + g_free(*pbp); + *pbp = NULL; } static PartiallyBalloonedPage *virtio_balloon_pbp_alloc(ram_addr_t base_gpa, @@ -108,8 +109,7 @@ static void balloon_inflate_page(VirtIOBalloon *balloon, /* We've partially ballooned part of a host page, but now * we're trying to balloon part of a different one. Too hard, * give up on the old partial page */ - virtio_balloon_pbp_free(*pbp); - *pbp = NULL; + virtio_balloon_pbp_free(pbp); } if (!*pbp) { @@ -127,8 +127,7 @@ static void balloon_inflate_page(VirtIOBalloon *balloon, /* We ignore errors from ram_block_discard_range(), because it * has already reported them, and failing to discard a balloon * page is not fatal */ - virtio_balloon_pbp_free(*pbp); - *pbp = NULL; + virtio_balloon_pbp_free(pbp); } } @@ -379,9 +378,8 @@ static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq) virtqueue_push(vq, elem, offset); virtio_notify(vdev, vq); g_free(elem); + virtio_balloon_pbp_free(&pbp); } - - virtio_balloon_pbp_free(pbp); } static void virtio_balloon_receive_stats(VirtIODevice *vdev, VirtQueue *vq) -- MST