diff mbox

[v2] scsi: pvscsi: limit process IO loop to ring size

Message ID 1473845952-30785-1-git-send-email-ppandit@redhat.com (mailing list archive)
State New, archived
Headers show

Commit Message

Prasad Pandit Sept. 14, 2016, 9:39 a.m. UTC 
From: Prasad J Pandit <pjp@fedoraproject.org>

Vmware Paravirtual SCSI emulator while processing IO requests
could run into an infinite loop if 'pvscsi_ring_pop_req_descr'
always returned positive value. Limit IO loop to the ring size.

Reported-by: Li Qiang <liqiang6-s@360.cn>
Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
---
 hw/scsi/vmw_pvscsi.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

Update per:
  -> https://lists.gnu.org/archive/html/qemu-devel/2016-09/msg02711.html

Comments

Paolo Bonzini Sept. 14, 2016, 9:59 a.m. UTC | #1 
On 14/09/2016 11:39, P J P wrote:
> From: Prasad J Pandit <pjp@fedoraproject.org>
> 
> Vmware Paravirtual SCSI emulator while processing IO requests
> could run into an infinite loop if 'pvscsi_ring_pop_req_descr'
> always returned positive value. Limit IO loop to the ring size.
> 
> Reported-by: Li Qiang <liqiang6-s@360.cn>
> Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
> ---
>  hw/scsi/vmw_pvscsi.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> Update per:
>   -> https://lists.gnu.org/archive/html/qemu-devel/2016-09/msg02711.html

Thanks, queued for 2.8.

Cc: qemu-stable@nongnu.org

Paolo

> diff --git a/hw/scsi/vmw_pvscsi.c b/hw/scsi/vmw_pvscsi.c
> index 4245c15..4d94b36 100644
> --- a/hw/scsi/vmw_pvscsi.c
> +++ b/hw/scsi/vmw_pvscsi.c
> @@ -245,8 +245,11 @@ static hwaddr
>  pvscsi_ring_pop_req_descr(PVSCSIRingInfo *mgr)
>  {
>      uint32_t ready_ptr = RS_GET_FIELD(mgr, reqProdIdx);
> +    uint32_t ring_size = PVSCSI_MAX_NUM_PAGES_REQ_RING
> +                            * PVSCSI_MAX_NUM_REQ_ENTRIES_PER_PAGE;
>  
> -    if (ready_ptr != mgr->consumed_ptr) {
> +    if (ready_ptr != mgr->consumed_ptr
> +        && ready_ptr - mgr->consumed_ptr < ring_size) {
>          uint32_t next_ready_ptr =
>              mgr->consumed_ptr++ & mgr->txr_len_mask;
>          uint32_t next_ready_page =
>
diff mbox

Patch

diff --git a/hw/scsi/vmw_pvscsi.c b/hw/scsi/vmw_pvscsi.c
index 4245c15..4d94b36 100644
--- a/hw/scsi/vmw_pvscsi.c
+++ b/hw/scsi/vmw_pvscsi.c
@@ -245,8 +245,11 @@  static hwaddr
 pvscsi_ring_pop_req_descr(PVSCSIRingInfo *mgr)
 {
     uint32_t ready_ptr = RS_GET_FIELD(mgr, reqProdIdx);
+    uint32_t ring_size = PVSCSI_MAX_NUM_PAGES_REQ_RING
+                            * PVSCSI_MAX_NUM_REQ_ENTRIES_PER_PAGE;
 
-    if (ready_ptr != mgr->consumed_ptr) {
+    if (ready_ptr != mgr->consumed_ptr
+        && ready_ptr - mgr->consumed_ptr < ring_size) {
         uint32_t next_ready_ptr =
             mgr->consumed_ptr++ & mgr->txr_len_mask;
         uint32_t next_ready_page =