[Qemu-devel] [PATCH v2 2/6] block: Acquire the AioContext in scsi_*_realize()

[Alberto Garcia <berto@igalia.com>]

This fixes a crash when adding a virtio-scsi device with a drive that
is using an iothread. Test case included.

Signed-off-by: Alberto Garcia <berto@igalia.com>
---
 hw/scsi/scsi-disk.c        | 23 ++++++++++++++++++++---
 tests/qemu-iotests/236     | 43 +++++++++++++++++++++++++++++++++++++++++++
 tests/qemu-iotests/236.out | 30 ++++++++++++++++++++++++++++++
 3 files changed, 93 insertions(+), 3 deletions(-)

diff --git a/hw/scsi/scsi-disk.c b/hw/scsi/scsi-disk.c
index 0e9027c8f3..b049026219 100644
--- a/hw/scsi/scsi-disk.c
+++ b/hw/scsi/scsi-disk.c
@@ -2381,10 +2381,13 @@ static void scsi_realize(SCSIDevice *dev, Error **errp)
 static void scsi_hd_realize(SCSIDevice *dev, Error **errp)
 {
     SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, dev);
+    AioContext *ctx = NULL;
     /* can happen for devices without drive. The error message for missing
      * backend will be issued in scsi_realize
      */
     if (s->qdev.conf.blk) {
+        ctx = blk_get_aio_context(s->qdev.conf.blk);
+        aio_context_acquire(ctx);
         blkconf_blocksizes(&s->qdev.conf);
     }
     s->qdev.blocksize = s->qdev.conf.logical_block_size;
@@ -2393,11 +2396,15 @@ static void scsi_hd_realize(SCSIDevice *dev, Error **errp)
         s->product = g_strdup("QEMU HARDDISK");
     }
     scsi_realize(&s->qdev, errp);
+    if (ctx) {
+        aio_context_release(ctx);
+    }
 }
 
 static void scsi_cd_realize(SCSIDevice *dev, Error **errp)
 {
     SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, dev);
+    AioContext *ctx;
     int ret;
 
     if (!dev->conf.blk) {
@@ -2408,6 +2415,8 @@ static void scsi_cd_realize(SCSIDevice *dev, Error **errp)
         assert(ret == 0);
     }
 
+    ctx = blk_get_aio_context(dev->conf.blk);
+    aio_context_acquire(ctx);
     s->qdev.blocksize = 2048;
     s->qdev.type = TYPE_ROM;
     s->features |= 1 << SCSI_DISK_F_REMOVABLE;
@@ -2415,6 +2424,7 @@ static void scsi_cd_realize(SCSIDevice *dev, Error **errp)
         s->product = g_strdup("QEMU CD-ROM");
     }
     scsi_realize(&s->qdev, errp);
+    aio_context_release(ctx);
 }
 
 static void scsi_disk_realize(SCSIDevice *dev, Error **errp)
@@ -2553,6 +2563,7 @@ static int get_device_type(SCSIDiskState *s)
 static void scsi_block_realize(SCSIDevice *dev, Error **errp)
 {
     SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, dev);
+    AioContext *ctx;
     int sg_version;
     int rc;
 
@@ -2567,6 +2578,9 @@ static void scsi_block_realize(SCSIDevice *dev, Error **errp)
                           "be removed in a future version");
     }
 
+    ctx = blk_get_aio_context(s->qdev.conf.blk);
+    aio_context_acquire(ctx);
+
     /* check we are using a driver managing SG_IO (version 3 and after) */
     rc = blk_ioctl(s->qdev.conf.blk, SG_GET_VERSION_NUM, &sg_version);
     if (rc < 0) {
@@ -2574,18 +2588,18 @@ static void scsi_block_realize(SCSIDevice *dev, Error **errp)
         if (rc != -EPERM) {
             error_append_hint(errp, "Is this a SCSI device?\n");
         }
-        return;
+        goto out;
     }
     if (sg_version < 30000) {
         error_setg(errp, "scsi generic interface too old");
-        return;
+        goto out;
     }
 
     /* get device type from INQUIRY data */
     rc = get_device_type(s);
     if (rc < 0) {
         error_setg(errp, "INQUIRY failed");
-        return;
+        goto out;
     }
 
     /* Make a guess for the block size, we'll fix it when the guest sends.
@@ -2605,6 +2619,9 @@ static void scsi_block_realize(SCSIDevice *dev, Error **errp)
 
     scsi_realize(&s->qdev, errp);
     scsi_generic_read_device_inquiry(&s->qdev);
+
+out:
+    aio_context_release(ctx);
 }
 
 typedef struct SCSIBlockReq {
diff --git a/tests/qemu-iotests/236 b/tests/qemu-iotests/236
index c6a3415ffe..c2bf425491 100755
--- a/tests/qemu-iotests/236
+++ b/tests/qemu-iotests/236
@@ -72,6 +72,49 @@ run_qemu <<EOF
 { "execute": "quit"}}
 EOF
 
+case "$QEMU_DEFAULT_MACHINE" in
+  s390-ccw-virtio)
+      virtio_scsi=virtio-scsi-ccw
+      ;;
+  *)
+      virtio_scsi=virtio-scsi-pci
+      ;;
+esac
+
+echo
+echo === Try adding and removing a virtio-scsi device with a hard drive ===
+echo
+
+run_qemu <<EOF
+{ "execute": "qmp_capabilities" }
+{ "execute": "blockdev-add", "arguments": {"driver": "null-co", "node-name": "hd0"}}
+{ "execute": "object-add", "arguments": {"qom-type": "iothread", "id": "iothread0"}}
+{ "execute": "x-blockdev-set-iothread", "arguments": {"node-name": "hd0", "iothread": "iothread0"}}
+{ "execute": "device_add", "arguments": {"id": "scsi0", "driver": "${virtio_scsi}"}}
+{ "execute": "device_add", "arguments": {"id": "scsi-hd0", "driver": "scsi-hd", "drive": "hd0"}}
+{ "execute": "device_del", "arguments": {"id": "scsi-hd0"}}
+{ "execute": "device_del", "arguments": {"id": "scsi0"}}
+{ "execute": "blockdev-del", "arguments": {"node-name": "hd0"}}
+{ "execute": "quit"}}
+EOF
+
+echo
+echo === Try adding and removing a virtio-scsi device with a CD ===
+echo
+
+run_qemu <<EOF
+{ "execute": "qmp_capabilities" }
+{ "execute": "blockdev-add", "arguments": {"driver": "null-co", "node-name": "cd0"}}
+{ "execute": "object-add", "arguments": {"qom-type": "iothread", "id": "iothread0"}}
+{ "execute": "x-blockdev-set-iothread", "arguments": {"node-name": "cd0", "iothread": "iothread0"}}
+{ "execute": "device_add", "arguments": {"id": "scsi0", "driver": "${virtio_scsi}"}}
+{ "execute": "device_add", "arguments": {"id": "scsi-cd0", "driver": "scsi-cd", "drive": "cd0"}}
+{ "execute": "device_del", "arguments": {"id": "scsi-cd0"}}
+{ "execute": "device_del", "arguments": {"id": "scsi0"}}
+{ "execute": "blockdev-del", "arguments": {"node-name": "cd0"}}
+{ "execute": "quit"}}
+EOF
+
 # success, all done
 echo "*** done"
 rm -f $seq.full
diff --git a/tests/qemu-iotests/236.out b/tests/qemu-iotests/236.out
index 01ee7b0b0d..2ad5aabcb3 100644
--- a/tests/qemu-iotests/236.out
+++ b/tests/qemu-iotests/236.out
@@ -13,4 +13,34 @@ QMP_VERSION
 {"return": {}}
 {"return": {}}
 {"return": {}}
+
+=== Try adding and removing a virtio-scsi device with a hard drive ===
+
+Testing:
+QMP_VERSION
+{"return": {}}
+{"return": {}}
+{"return": {}}
+{"return": {}}
+{"return": {}}
+{"return": {}}
+{"return": {}}
+{"return": {}}
+{"return": {}}
+{"return": {}}
+
+=== Try adding and removing a virtio-scsi device with a CD ===
+
+Testing:
+QMP_VERSION
+{"return": {}}
+{"return": {}}
+{"return": {}}
+{"return": {}}
+{"return": {}}
+{"return": {}}
+{"return": {}}
+{"return": {}}
+{"return": {}}
+{"return": {}}
 *** done
-- 
2.11.0