[libvirt] [PATCH] qemu: fix inf-loop in blkio parameters

Eric Blake eblake at redhat.com
Wed Dec 28 13:57:34 UTC 2011


https://bugzilla.redhat.com/show_bug.cgi?id=770520

We had two nested loops both trying to use 'i' as the iteration
variable, which can result in an infinite loop when the inner
loop interferes with the outer loop.  Introduced in commit 93ab585.

* src/qemu/qemu_driver.c (qemuDomainSetBlkioParameters): Don't
reuse iteration variable across two loops.
---

Pushing under the trivial rule.

 src/qemu/qemu_driver.c |   12 +++++++-----
 1 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index eeeb935..a840c1f 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -5982,6 +5982,8 @@ static int qemuDomainSetBlkioParameters(virDomainPtr dom,
             } else if (STREQ(param->field, VIR_DOMAIN_BLKIO_DEVICE_WEIGHT)) {
                 size_t ndevices;
                 virBlkioDeviceWeightPtr devices = NULL;
+                int j;
+
                 if (param->type != VIR_TYPED_PARAM_STRING) {
                     qemuReportError(VIR_ERR_INVALID_ARG, "%s",
                                     _("invalid type for device_weight tunable, "
@@ -5996,19 +5998,19 @@ static int qemuDomainSetBlkioParameters(virDomainPtr dom,
                     ret = -1;
                     continue;
                 }
-                for (i = 0; i < ndevices; i++) {
+                for (j = 0; j < ndevices; i++) {
                     rc = virCgroupSetBlkioDeviceWeight(group,
-                                                       devices[i].path,
-                                                       devices[i].weight);
+                                                       devices[j].path,
+                                                       devices[j].weight);
                     if (rc < 0) {
                         virReportSystemError(-rc,
                                              _("Unable to set io device weight "
                                                "for path %s"),
-                                             devices[i].path);
+                                             devices[j].path);
                         break;
                     }
                 }
-                if (i != ndevices) {
+                if (j != ndevices) {
                     ret = -1;
                     continue;
                 }
-- 
1.7.7.4




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