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error: Avoid error_propagate() after migrate_add_blocker()
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When migrate_add_blocker(blocker, &errp) is followed by
error_propagate(errp, err), we can often just as well do
migrate_add_blocker(..., errp).

Do that with this Coccinelle script:

    @@
    expression blocker, err, errp;
    expression ret;
    @@
    -    ret = migrate_add_blocker(blocker, &err);
    -    if (err) {
    +    ret = migrate_add_blocker(blocker, errp);
    +    if (ret < 0) {
             ... when != err;
    -        error_propagate(errp, err);
             ...
         }

    @@
    expression blocker, err, errp;
    @@
    -    migrate_add_blocker(blocker, &err);
    -    if (err) {
    +    if (migrate_add_blocker(blocker, errp) < 0) {
             ... when != err;
    -        error_propagate(errp, err);
             ...
         }

Double-check @err is not used afterwards.  Dereferencing it would be
use after free, but checking whether it's null would be legitimate.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20200707160613.848843-43-armbru@redhat.com>
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Markus Armbruster committed Jul 10, 2020
1 parent 7b3cb80 commit 386f6c0
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Showing 13 changed files with 20 additions and 45 deletions.
5 changes: 2 additions & 3 deletions block/parallels.c
View file
Expand Up @@ -859,9 +859,8 @@ static int parallels_open(BlockDriverState *bs, QDict *options, int flags,
error_setg(&s->migration_blocker, "The Parallels format used by node '%s' "
"does not support live migration",
bdrv_get_device_or_node_name(bs));
ret = migrate_add_blocker(s->migration_blocker, &local_err);
if (local_err) {
error_propagate(errp, local_err);
ret = migrate_add_blocker(s->migration_blocker, errp);
if (ret < 0) {
error_free(s->migration_blocker);
goto fail;
}
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6 changes: 2 additions & 4 deletions block/qcow.c
View file
Expand Up @@ -121,7 +121,6 @@ static int qcow_open(BlockDriverState *bs, QDict *options, int flags,
unsigned int len, i, shift;
int ret;
QCowHeader header;
Error *local_err = NULL;
QCryptoBlockOpenOptions *crypto_opts = NULL;
unsigned int cflags = 0;
QDict *encryptopts = NULL;
Expand Down Expand Up @@ -314,9 +313,8 @@ static int qcow_open(BlockDriverState *bs, QDict *options, int flags,
error_setg(&s->migration_blocker, "The qcow format used by node '%s' "
"does not support live migration",
bdrv_get_device_or_node_name(bs));
ret = migrate_add_blocker(s->migration_blocker, &local_err);
if (local_err) {
error_propagate(errp, local_err);
ret = migrate_add_blocker(s->migration_blocker, errp);
if (ret < 0) {
error_free(s->migration_blocker);
goto fail;
}
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6 changes: 2 additions & 4 deletions block/vdi.c
View file
Expand Up @@ -374,7 +374,6 @@ static int vdi_open(BlockDriverState *bs, QDict *options, int flags,
VdiHeader header;
size_t bmap_size;
int ret;
Error *local_err = NULL;
QemuUUID uuid_link, uuid_parent;

bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds,
Expand Down Expand Up @@ -495,9 +494,8 @@ static int vdi_open(BlockDriverState *bs, QDict *options, int flags,
error_setg(&s->migration_blocker, "The vdi format used by node '%s' "
"does not support live migration",
bdrv_get_device_or_node_name(bs));
ret = migrate_add_blocker(s->migration_blocker, &local_err);
if (local_err) {
error_propagate(errp, local_err);
ret = migrate_add_blocker(s->migration_blocker, errp);
if (ret < 0) {
error_free(s->migration_blocker);
goto fail_free_bmap;
}
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5 changes: 2 additions & 3 deletions block/vhdx.c
View file
Expand Up @@ -1089,9 +1089,8 @@ static int vhdx_open(BlockDriverState *bs, QDict *options, int flags,
error_setg(&s->migration_blocker, "The vhdx format used by node '%s' "
"does not support live migration",
bdrv_get_device_or_node_name(bs));
ret = migrate_add_blocker(s->migration_blocker, &local_err);
if (local_err) {
error_propagate(errp, local_err);
ret = migrate_add_blocker(s->migration_blocker, errp);
if (ret < 0) {
error_free(s->migration_blocker);
goto fail;
}
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6 changes: 2 additions & 4 deletions block/vmdk.c
View file
Expand Up @@ -1263,7 +1263,6 @@ static int vmdk_open(BlockDriverState *bs, QDict *options, int flags,
int ret;
BDRVVmdkState *s = bs->opaque;
uint32_t magic;
Error *local_err = NULL;

bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds,
BDRV_CHILD_IMAGE, false, errp);
Expand Down Expand Up @@ -1317,9 +1316,8 @@ static int vmdk_open(BlockDriverState *bs, QDict *options, int flags,
error_setg(&s->migration_blocker, "The vmdk format used by node '%s' "
"does not support live migration",
bdrv_get_device_or_node_name(bs));
ret = migrate_add_blocker(s->migration_blocker, &local_err);
if (local_err) {
error_propagate(errp, local_err);
ret = migrate_add_blocker(s->migration_blocker, errp);
if (ret < 0) {
error_free(s->migration_blocker);
goto fail;
}
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5 changes: 2 additions & 3 deletions block/vpc.c
View file
Expand Up @@ -446,9 +446,8 @@ static int vpc_open(BlockDriverState *bs, QDict *options, int flags,
error_setg(&s->migration_blocker, "The vpc format used by node '%s' "
"does not support live migration",
bdrv_get_device_or_node_name(bs));
ret = migrate_add_blocker(s->migration_blocker, &local_err);
if (local_err) {
error_propagate(errp, local_err);
ret = migrate_add_blocker(s->migration_blocker, errp);
if (ret < 0) {
error_free(s->migration_blocker);
goto fail;
}
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6 changes: 2 additions & 4 deletions block/vvfat.c
View file
Expand Up @@ -1141,7 +1141,6 @@ static int vvfat_open(BlockDriverState *bs, QDict *options, int flags,
bool floppy;
const char *dirname, *label;
QemuOpts *opts;
Error *local_err = NULL;
int ret;

#ifdef DEBUG
Expand Down Expand Up @@ -1267,9 +1266,8 @@ static int vvfat_open(BlockDriverState *bs, QDict *options, int flags,
"The vvfat (rw) format used by node '%s' "
"does not support live migration",
bdrv_get_device_or_node_name(bs));
ret = migrate_add_blocker(s->migration_blocker, &local_err);
if (local_err) {
error_propagate(errp, local_err);
ret = migrate_add_blocker(s->migration_blocker, errp);
if (ret < 0) {
error_free(s->migration_blocker);
goto fail;
}
Expand Down
5 changes: 1 addition & 4 deletions hw/display/virtio-gpu-base.c
View file
Expand Up @@ -128,7 +128,6 @@ virtio_gpu_base_device_realize(DeviceState *qdev,
{
VirtIODevice *vdev = VIRTIO_DEVICE(qdev);
VirtIOGPUBase *g = VIRTIO_GPU_BASE(qdev);
Error *local_err = NULL;
int i;

if (g->conf.max_outputs > VIRTIO_GPU_MAX_SCANOUTS) {
Expand All @@ -139,9 +138,7 @@ virtio_gpu_base_device_realize(DeviceState *qdev,
g->use_virgl_renderer = false;
if (virtio_gpu_virgl_enabled(g->conf)) {
error_setg(&g->migration_blocker, "virgl is not yet migratable");
migrate_add_blocker(g->migration_blocker, &local_err);
if (local_err) {
error_propagate(errp, local_err);
if (migrate_add_blocker(g->migration_blocker, errp) < 0) {
error_free(g->migration_blocker);
return false;
}
Expand Down
4 changes: 1 addition & 3 deletions hw/intc/arm_gic_kvm.c
View file
Expand Up @@ -517,9 +517,7 @@ static void kvm_arm_gic_realize(DeviceState *dev, Error **errp)
if (!kvm_arm_gic_can_save_restore(s)) {
error_setg(&s->migration_blocker, "This operating system kernel does "
"not support vGICv2 migration");
migrate_add_blocker(s->migration_blocker, &local_err);
if (local_err) {
error_propagate(errp, local_err);
if (migrate_add_blocker(s->migration_blocker, errp) < 0) {
error_free(s->migration_blocker);
return;
}
Expand Down
5 changes: 1 addition & 4 deletions hw/intc/arm_gicv3_its_kvm.c
View file
Expand Up @@ -91,7 +91,6 @@ static void vm_change_state_handler(void *opaque, int running,
static void kvm_arm_its_realize(DeviceState *dev, Error **errp)
{
GICv3ITSState *s = ARM_GICV3_ITS_COMMON(dev);
Error *local_err = NULL;

s->dev_fd = kvm_create_device(kvm_state, KVM_DEV_TYPE_ARM_VGIC_ITS, false);
if (s->dev_fd < 0) {
Expand All @@ -113,9 +112,7 @@ static void kvm_arm_its_realize(DeviceState *dev, Error **errp)
GITS_CTLR)) {
error_setg(&s->migration_blocker, "This operating system kernel "
"does not support vITS migration");
migrate_add_blocker(s->migration_blocker, &local_err);
if (local_err) {
error_propagate(errp, local_err);
if (migrate_add_blocker(s->migration_blocker, errp) < 0) {
error_free(s->migration_blocker);
return;
}
Expand Down
4 changes: 1 addition & 3 deletions hw/intc/arm_gicv3_kvm.c
View file
Expand Up @@ -858,9 +858,7 @@ static void kvm_arm_gicv3_realize(DeviceState *dev, Error **errp)
GICD_CTLR)) {
error_setg(&s->migration_blocker, "This operating system kernel does "
"not support vGICv3 migration");
migrate_add_blocker(s->migration_blocker, &local_err);
if (local_err) {
error_propagate(errp, local_err);
if (migrate_add_blocker(s->migration_blocker, errp) < 0) {
error_free(s->migration_blocker);
return;
}
Expand Down
4 changes: 1 addition & 3 deletions hw/misc/ivshmem.c
View file
Expand Up @@ -898,9 +898,7 @@ static void ivshmem_common_realize(PCIDevice *dev, Error **errp)
if (!ivshmem_is_master(s)) {
error_setg(&s->migration_blocker,
"Migration is disabled when using feature 'peer mode' in device 'ivshmem'");
migrate_add_blocker(s->migration_blocker, &err);
if (err) {
error_propagate(errp, err);
if (migrate_add_blocker(s->migration_blocker, errp) < 0) {
error_free(s->migration_blocker);
return;
}
Expand Down
4 changes: 1 addition & 3 deletions hw/scsi/vhost-scsi.c
View file
Expand Up @@ -207,9 +207,7 @@ static void vhost_scsi_realize(DeviceState *dev, Error **errp)
"When external environment supports it (Orchestrator migrates "
"target SCSI device state or use shared storage over network), "
"set 'migratable' property to true to enable migration.");
migrate_add_blocker(vsc->migration_blocker, &err);
if (err) {
error_propagate(errp, err);
if (migrate_add_blocker(vsc->migration_blocker, errp) < 0) {
error_free(vsc->migration_blocker);
goto free_virtio;
}
Expand Down

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