From 038268e2e8087ee2fd8987a77ba580e15f14c147 Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Tue, 20 Nov 2012 17:27:43 +0100 Subject: [PATCH] ide: Fix crash with too long PRD 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 Signed-off-by: Stefan Hajnoczi --- hw/ide/core.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/hw/ide/core.c b/hw/ide/core.c index 7d6b0fa7b4..c2ab78753a 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)