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From: Markus Armbruster <armbru@redhat.com>
To: qemu-devel@nongnu.org
Cc: peter.maydell@linaro.org, vsementsov@virtuozzo.com,
	berrange@redhat.com, ehabkost@redhat.com, qemu-block@nongnu.org,
	groug@kaod.org, pbonzini@redhat.com
Subject: [PATCH v3 41/44] error: Avoid error_propagate() after migrate_add_blocker()
Date: Mon,  6 Jul 2020 10:09:47 +0200	[thread overview]
Message-ID: <20200706080950.403087-42-armbru@redhat.com> (raw)
In-Reply-To: <20200706080950.403087-1-armbru@redhat.com>

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>
---
 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                | 6 ++----
 hw/display/virtio-gpu-base.c | 5 +----
 hw/intc/arm_gic_kvm.c        | 4 +---
 hw/intc/arm_gicv3_its_kvm.c  | 5 +----
 hw/intc/arm_gicv3_kvm.c      | 4 +---
 hw/misc/ivshmem.c            | 4 +---
 hw/scsi/vhost-scsi.c         | 4 +---
 13 files changed, 20 insertions(+), 45 deletions(-)

diff --git a/block/parallels.c b/block/parallels.c
index f489c0d4ba..3c22dfdc9d 100644
--- a/block/parallels.c
+++ b/block/parallels.c
@@ -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;
     }
diff --git a/block/qcow.c b/block/qcow.c
index c22d1bf6b8..1e134f3445 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 0a60be773e..3a3df45f84 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 eed9c3b860..1f9fca837d 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 77043c2424..259d0ad2fe 100644
--- a/block/vpc.c
+++ b/block/vpc.c
@@ -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;
     }
diff --git a/block/vvfat.c b/block/vvfat.c
index 24d36220d3..36b53c8757 100644
--- a/block/vvfat.c
+++ b/block/vvfat.c
@@ -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
@@ -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;
         }
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..46835ed085 100644
--- a/hw/intc/arm_gicv3_its_kvm.c
+++ b/hw/intc/arm_gicv3_its_kvm.c
@@ -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) {
@@ -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;
         }
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;
         }
-- 
2.26.2



  parent reply	other threads:[~2020-07-06  8:18 UTC|newest]

Thread overview: 65+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-06  8:09 [PATCH v3 00/44] Less clumsy error checking Markus Armbruster
2020-07-06  8:09 ` [PATCH v3 01/44] error: Improve examples in error.h's big comment Markus Armbruster
2020-07-06 14:33   ` Markus Armbruster
2020-07-06  8:09 ` [PATCH v3 02/44] error: Document Error API usage rules Markus Armbruster
2020-07-06  8:09 ` [PATCH v3 03/44] qdev: Use returned bool to check for qdev_realize() etc. failure Markus Armbruster
2020-07-06 10:08   ` Greg Kurz
2020-07-06 11:35     ` Markus Armbruster
2020-07-06 14:43       ` Greg Kurz
2020-07-06  8:09 ` [PATCH v3 04/44] macio: Tidy up error handling in macio_newworld_realize() Markus Armbruster
2020-07-06 14:47   ` Greg Kurz
2020-07-06  8:09 ` [PATCH v3 05/44] virtio-crypto-pci: Tidy up virtio_crypto_pci_realize() Markus Armbruster
2020-07-06  8:09 ` [PATCH v3 06/44] qemu-option: Check return value instead of @err where convenient Markus Armbruster
2020-07-06 15:59   ` Greg Kurz
2020-07-06 20:01     ` Markus Armbruster
2020-07-07  8:25       ` Greg Kurz
2020-07-06  8:09 ` [PATCH v3 07/44] qemu-option: Make uses of find_desc_by_name() more similar Markus Armbruster
2020-07-07  8:26   ` Greg Kurz
2020-07-06  8:09 ` [PATCH v3 08/44] qemu-option: Factor out helper find_default_by_name() Markus Armbruster
2020-07-07  8:47   ` Greg Kurz
2020-07-06  8:09 ` [PATCH v3 09/44] qemu-option: Simplify around find_default_by_name() Markus Armbruster
2020-07-06  8:09 ` [PATCH v3 10/44] qemu-option: Factor out helper opt_create() Markus Armbruster
2020-07-06  8:09 ` [PATCH v3 11/44] qemu-option: Replace opt_set() by cleaner opt_validate() Markus Armbruster
2020-07-06  8:09 ` [PATCH v3 12/44] qemu-option: Make functions taking Error ** return bool, not void Markus Armbruster
2020-07-06  8:09 ` [PATCH v3 13/44] qemu-option: Use returned bool to check for failure Markus Armbruster
2020-07-06  8:09 ` [PATCH v3 14/44] block: Avoid error accumulation in bdrv_img_create() Markus Armbruster
2020-07-06  8:09 ` [PATCH v3 15/44] hmp: Eliminate a variable in hmp_migrate_set_parameter() Markus Armbruster
2020-07-06  8:09 ` [PATCH v3 16/44] qapi: Make visitor functions taking Error ** return bool, not void Markus Armbruster
2020-07-06  8:09 ` [PATCH v3 17/44] qapi: Use returned bool to check for failure, Coccinelle part Markus Armbruster
2020-07-06  8:09 ` [PATCH v3 18/44] qapi: Use returned bool to check for failure, manual part Markus Armbruster
2020-07-06  8:09 ` [PATCH v3 19/44] s390x/pci: Fix harmless mistake in zpci's property fid's setter Markus Armbruster
2020-07-06  8:09 ` [PATCH v3 20/44] qom: Use error_reportf_err() instead of g_printerr() in examples Markus Armbruster
2020-07-06  8:09 ` [PATCH v3 21/44] qom: Rename qdev_get_type() to object_get_type() Markus Armbruster
2020-07-06  8:09 ` [PATCH v3 22/44] qom: Crash more nicely on object_property_get_link() failure Markus Armbruster
2020-07-06  8:09 ` [PATCH v3 23/44] qom: Don't handle impossible " Markus Armbruster
2020-07-06  8:09 ` [PATCH v3 24/44] qom: Use return values to check for error where that's simpler Markus Armbruster
2020-07-06 11:23   ` Vladimir Sementsov-Ogievskiy
2020-07-06  8:09 ` [PATCH v3 25/44] qom: Put name parameter before value / visitor parameter Markus Armbruster
2020-07-06 15:19   ` Vladimir Sementsov-Ogievskiy
2020-07-06  8:09 ` [PATCH v3 26/44] qom: Make functions taking Error ** return bool, not void Markus Armbruster
2020-07-06 15:44   ` Vladimir Sementsov-Ogievskiy
2020-07-06  8:09 ` [PATCH v3 27/44] qom: Use returned bool to check for failure, Coccinelle part Markus Armbruster
2020-07-06 16:08   ` Vladimir Sementsov-Ogievskiy
2020-07-06  8:09 ` [PATCH v3 28/44] qom: Use returned bool to check for failure, manual part Markus Armbruster
2020-07-06 16:39   ` Vladimir Sementsov-Ogievskiy
2020-07-06  8:09 ` [PATCH v3 29/44] qom: Make functions taking Error ** return bool, not 0/-1 Markus Armbruster
2020-07-06 16:52   ` Vladimir Sementsov-Ogievskiy
2020-07-06 20:07     ` Markus Armbruster
2020-07-06  8:09 ` [PATCH v3 30/44] qdev: Make functions taking Error ** return bool, not void Markus Armbruster
2020-07-06 16:58   ` Vladimir Sementsov-Ogievskiy
2020-07-06  8:09 ` [PATCH v3 31/44] qdev: Use returned bool to check for failure, Coccinelle part Markus Armbruster
2020-07-06  8:09 ` [PATCH v3 32/44] error: Avoid unnecessary error_propagate() after error_setg() Markus Armbruster
2020-07-06  8:09 ` [PATCH v3 33/44] error: Eliminate error_propagate() with Coccinelle, part 1 Markus Armbruster
2020-07-06  8:09 ` [PATCH v3 34/44] error: Eliminate error_propagate() with Coccinelle, part 2 Markus Armbruster
2020-07-06  8:09 ` [PATCH v3 35/44] error: Eliminate error_propagate() manually Markus Armbruster
2020-07-06  8:09 ` [PATCH v3 36/44] error: Reduce unnecessary error propagation Markus Armbruster
2020-07-06  8:09 ` [PATCH v3 37/44] block/parallels: Simplify parallels_open() after previous commit Markus Armbruster
2020-07-06  8:09 ` [PATCH v3 38/44] qapi: Smooth another visitor error checking pattern Markus Armbruster
2020-07-06  8:09 ` [PATCH v3 39/44] qapi: Smooth visitor error checking in generated code Markus Armbruster
2020-07-06  8:09 ` [PATCH v3 40/44] qapi: Purge error_propagate() from QAPI core Markus Armbruster
2020-07-06  8:09 ` Markus Armbruster [this message]
2020-07-06  8:09 ` [PATCH v3 42/44] qemu-img: Ignore Error objects where the return value suffices Markus Armbruster
2020-07-06  8:09 ` [PATCH v3 43/44] qdev: " Markus Armbruster
2020-07-06  8:09 ` [PATCH v3 44/44] hmp: " Markus Armbruster
2020-07-06  8:12 ` [PATCH v3 00/44] Less clumsy error checking Markus Armbruster
2020-07-06 13:44   ` Eric Blake

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