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From: P J P <ppandit@redhat.com>
To: Qemu Developers <qemu-devel@nongnu.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
	Dmitry Fleytman <dmitry@daynix.com>, Li Qiang <liqiang6-s@360.cn>,
	Prasad J Pandit <pjp@fedoraproject.org>
Subject: [Qemu-devel] [PATCH] scsi: pvscsi: limit process IO loop to maximum page count
Date: Wed,  7 Sep 2016 10:13:28 +0530	[thread overview]
Message-ID: <1473223408-24079-1-git-send-email-ppandit@redhat.com> (raw)

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 maximum
page count.

Reported-by: Li Qiang <liqiang6-s@360.cn>
Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
---
 hw/scsi/vmw_pvscsi.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/hw/scsi/vmw_pvscsi.c b/hw/scsi/vmw_pvscsi.c
index babac5a..3e77a08 100644
--- a/hw/scsi/vmw_pvscsi.c
+++ b/hw/scsi/vmw_pvscsi.c
@@ -711,11 +711,13 @@ pvscsi_process_request_descriptor(PVSCSIState *s,
 static void
 pvscsi_process_io(PVSCSIState *s)
 {
+    int descr_pa_cnt = 0;
     PVSCSIRingReqDesc descr;
     hwaddr next_descr_pa;
 
     assert(s->rings_info_valid);
-    while ((next_descr_pa = pvscsi_ring_pop_req_descr(&s->rings)) != 0) {
+    while (((next_descr_pa = pvscsi_ring_pop_req_descr(&s->rings)) != 0)
+            && descr_pa_cnt++ < PVSCSI_SETUP_RINGS_MAX_NUM_PAGES) {
 
         /* Only read after production index verification */
         smp_rmb();
-- 
2.5.5

             reply	other threads:[~2016-09-07  4:43 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-09-07  4:43 P J P [this message]
2016-09-13  7:00 ` [Qemu-devel] [PATCH] scsi: pvscsi: limit process IO loop to maximum page count P J P
2016-09-13  8:31   ` Dmitry Fleytman
2016-09-13 10:48     ` P J P
2016-09-13 12:10       ` Dmitry Fleytman
2016-09-13 13:09         ` P J P

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