diff mbox series

[09/46] error: Avoid error_propagate() after migrate_add_blocker()

Message ID 20200624164344.3778251-10-armbru@redhat.com
State New
Headers show
Series Less clumsy error checking | expand

Commit Message

Markus Armbruster June 24, 2020, 4:43 p.m. UTC 
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>
---
 block/parallels.c            | 5 ++---
 block/qcow.c                 | 6 ++----
 block/vdi.c                  | 6 ++----
 block/vhdx.c                 | 5 ++---
 block/vmdk.c                 | 6 ++----
 block/vpc.c                  | 5 ++---
 block/vvfat.c                | 5 ++---
 hw/display/virtio-gpu-base.c | 5 +----
 hw/intc/arm_gic_kvm.c        | 4 +---
 hw/intc/arm_gicv3_its_kvm.c  | 4 +---
 hw/intc/arm_gicv3_kvm.c      | 4 +---
 hw/misc/ivshmem.c            | 4 +---
 hw/scsi/vhost-scsi.c         | 4 +---
 13 files changed, 20 insertions(+), 43 deletions(-)

Comments

Eric Blake June 24, 2020, 7:34 p.m. UTC | #1 
On 6/24/20 11:43 AM, Markus Armbruster wrote:
> 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:

> 
> 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>
Vladimir Sementsov-Ogievskiy June 29, 2020, 8:29 a.m. UTC | #2 
24.06.2020 19:43, Markus Armbruster wrote:
> 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>
> ---
>   block/parallels.c            | 5 ++---
>   block/qcow.c                 | 6 ++----
>   block/vdi.c                  | 6 ++----
>   block/vhdx.c                 | 5 ++---
>   block/vmdk.c                 | 6 ++----
>   block/vpc.c                  | 5 ++---
>   block/vvfat.c                | 5 ++---
>   hw/display/virtio-gpu-base.c | 5 +----
>   hw/intc/arm_gic_kvm.c        | 4 +---
>   hw/intc/arm_gicv3_its_kvm.c  | 4 +---
>   hw/intc/arm_gicv3_kvm.c      | 4 +---
>   hw/misc/ivshmem.c            | 4 +---
>   hw/scsi/vhost-scsi.c         | 4 +---
>   13 files changed, 20 insertions(+), 43 deletions(-)
> 

[..]

> diff --git a/hw/intc/arm_gicv3_its_kvm.c b/hw/intc/arm_gicv3_its_kvm.c
> index ad0ebabc87..87bc4aeca1 100644
> --- a/hw/intc/arm_gicv3_its_kvm.c
> +++ b/hw/intc/arm_gicv3_its_kvm.c
> @@ -113,9 +113,7 @@ static void kvm_arm_its_realize(DeviceState *dev, Error **errp)

Remove unused local_err

with fixed:
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

>           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;
>           }

[..]
diff mbox series

Patch

diff --git a/block/parallels.c b/block/parallels.c
index a84ec6a518..860dbb80a2 100644
--- a/block/parallels.c
+++ b/block/parallels.c
@@ -862,9 +862,8 @@  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;
     }
diff --git a/block/qcow.c b/block/qcow.c
index dca2a1fe7d..eefa3b63da 100644
--- a/block/qcow.c
+++ b/block/qcow.c
@@ -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;
@@ -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;
     }
diff --git a/block/vdi.c b/block/vdi.c
index 2f506a01ba..5fca67f52d 100644
--- a/block/vdi.c
+++ b/block/vdi.c
@@ -375,7 +375,6 @@  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,
@@ -496,9 +495,8 @@  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;
     }
diff --git a/block/vhdx.c b/block/vhdx.c
index ac5a9094c4..b9ef4ff074 100644
--- a/block/vhdx.c
+++ b/block/vhdx.c
@@ -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;
     }
diff --git a/block/vmdk.c b/block/vmdk.c
index 9a09193f3b..28cec50f38 100644
--- a/block/vmdk.c
+++ b/block/vmdk.c
@@ -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);
@@ -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;
     }
diff --git a/block/vpc.c b/block/vpc.c
index 36412f764d..7290f36514 100644
--- a/block/vpc.c
+++ b/block/vpc.c
@@ -448,9 +448,8 @@  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;
     }
diff --git a/block/vvfat.c b/block/vvfat.c
index c65a98e3ee..a28e3fa442 100644
--- a/block/vvfat.c
+++ b/block/vvfat.c
@@ -1282,9 +1282,8 @@  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;
         }
diff --git a/hw/display/virtio-gpu-base.c b/hw/display/virtio-gpu-base.c
index c159351be3..7961308606 100644
--- a/hw/display/virtio-gpu-base.c
+++ b/hw/display/virtio-gpu-base.c
@@ -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) {
@@ -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;
         }
diff --git a/hw/intc/arm_gic_kvm.c b/hw/intc/arm_gic_kvm.c
index d7df423a7a..07b95143c9 100644
--- a/hw/intc/arm_gic_kvm.c
+++ b/hw/intc/arm_gic_kvm.c
@@ -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;
         }
diff --git a/hw/intc/arm_gicv3_its_kvm.c b/hw/intc/arm_gicv3_its_kvm.c
index ad0ebabc87..87bc4aeca1 100644
--- a/hw/intc/arm_gicv3_its_kvm.c
+++ b/hw/intc/arm_gicv3_its_kvm.c
@@ -113,9 +113,7 @@  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;
         }
diff --git a/hw/intc/arm_gicv3_kvm.c b/hw/intc/arm_gicv3_kvm.c
index ca43bf87ca..eddd07c743 100644
--- a/hw/intc/arm_gicv3_kvm.c
+++ b/hw/intc/arm_gicv3_kvm.c
@@ -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;
         }
diff --git a/hw/misc/ivshmem.c b/hw/misc/ivshmem.c
index a8dc9b377d..fc128b25e2 100644
--- a/hw/misc/ivshmem.c
+++ b/hw/misc/ivshmem.c
@@ -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;
         }
diff --git a/hw/scsi/vhost-scsi.c b/hw/scsi/vhost-scsi.c
index c1b012aea4..13b05af29b 100644
--- a/hw/scsi/vhost-scsi.c
+++ b/hw/scsi/vhost-scsi.c
@@ -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;
         }