From patchwork Tue Nov 20 16:27:43 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [1/2] ide: Fix crash with too long PRD Date: Tue, 20 Nov 2012 06:27:43 -0000 From: Kevin Wolf X-Patchwork-Id: 200389 Message-Id: <1353428864-19505-2-git-send-email-kwolf@redhat.com> To: stefanha@redhat.com Cc: kwolf@redhat.com, qemu-devel@nongnu.org Without this, s->nsector can become negative and badness happens (trying to malloc huge amount of memory and glib calls abort()) Signed-off-by: Kevin Wolf --- hw/ide/core.c | 12 ++++++++++++ 1 files changed, 12 insertions(+), 0 deletions(-) diff --git a/hw/ide/core.c b/hw/ide/core.c index 7d6b0fa..c2ab787 100644 --- a/hw/ide/core.c +++ b/hw/ide/core.c @@ -579,6 +579,7 @@ void ide_dma_cb(void *opaque, int ret) IDEState *s = opaque; int n; int64_t sector_num; + bool stay_active = false; if (ret < 0) { int op = BM_STATUS_DMA_RETRY; @@ -594,6 +595,14 @@ void ide_dma_cb(void *opaque, int ret) } n = s->io_buffer_size >> 9; + if (n > s->nsector) { + /* The PRDs were longer than needed for this request. Shorten them so + * we don't get a negative remainder. The Active bit must remain set + * after the request completes. */ + n = s->nsector; + stay_active = true; + } + sector_num = ide_get_sector(s); if (n > 0) { dma_buf_commit(s); @@ -646,6 +655,9 @@ eot: bdrv_acct_done(s->bs, &s->acct); } ide_set_inactive(s); + if (stay_active) { + s->bus->dma->ops->add_status(s->bus->dma, BM_STATUS_DMAING); + } } static void ide_sector_start_dma(IDEState *s, enum ide_dma_cmd dma_cmd)