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throttle: Remove block from group on hot-unplug

PATCH Applied Eric Blake 3 participants 3 messages Apr 6, 2017 – Apr 7, 2017 Block layer

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Eric Blake

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#0 lore raw

PATCH 1/1 throttle: Remove block from group on hot-unplug

When a block device that is part of a throttle group is hot-unplugged, we forgot to remove it from the throttle group. This leaves stale memory around, and causes an easily reproducible crash:

$ ./x86_64-softmmu/qemu-system-x86_64 -nodefaults -nographic -qmp stdio \
-device virtio-scsi-pci,bus=pci.0 -drive \
id=drive_image2,if=none,format=raw,file=file2,bps=512000,iops=100,group=foo \
-device scsi-hd,id=image2,drive=drive_image2 -drive \
id=drive_image3,if=none,format=raw,file=file3,bps=512000,iops=100,group=foo \
-device scsi-hd,id=image3,drive=drive_image3
{'execute':'qmp_capabilities'}
{'execute':'device_del','arguments':{'id':'image3'}}
{'execute':'system_reset'}
Fixes https://bugzilla.redhat.com/show_bug.cgi?id=1428810
Suggested-by Alberto Garcia <[email protected]>
Signed-off-by Eric Blake <[email protected]>
---
 block/block-backend.c | 3 +++
 1 file changed, 3 insertions(+)
block/block-backend.c +3 -0
index 0b63773..d27c3a3 100644
@@ -230,6 +230,9 @@ static void blk_delete(BlockBackend *blk)
     assert(!blk->refcnt);
     assert(!blk->name);
     assert(!blk->dev);
+    if (blk->public.throttle_state) {
+        blk_io_limits_disable(blk);
+    }
     if (blk->root) {
         blk_remove_bs(blk);
     }
Signature · 1 line
2.9.3
Applied
#1 lore raw
Quoted 14 lines · Eric Blake

When a block device that is part of a throttle group is hot-unplugged, we forgot to remove it from the throttle group. This leaves stale memory around, and causes an easily reproducible crash:

$ ./x86_64-softmmu/qemu-system-x86_64 -nodefaults -nographic -qmp stdio \
-device virtio-scsi-pci,bus=pci.0 -drive \
id=drive_image2,if=none,format=raw,file=file2,bps=512000,iops=100,group=foo \
-device scsi-hd,id=image2,drive=drive_image2 -drive \
id=drive_image3,if=none,format=raw,file=file3,bps=512000,iops=100,group=foo \
-device scsi-hd,id=image3,drive=drive_image3
{'execute':'qmp_capabilities'}
{'execute':'device_del','arguments':{'id':'image3'}}
{'execute':'system_reset'}
Quoted 7 lines
Fixes https://bugzilla.redhat.com/show_bug.cgi?id=1428810
Suggested-by Alberto Garcia <[email protected]>
Signed-off-by Eric Blake <[email protected]>
---
 block/block-backend.c | 3 +++
 1 file changed, 3 insertions(+)

Thanks, applied to my block branch:

https://github.com/XanClic/qemu/commits/block

Max

Reviewed-by on v1 1/1
#2 lore raw
In reply to Eric Blake
Quoted 14 lines · Eric Blake

When a block device that is part of a throttle group is hot-unplugged, we forgot to remove it from the throttle group. This leaves stale memory around, and causes an easily reproducible crash:

$ ./x86_64-softmmu/qemu-system-x86_64 -nodefaults -nographic -qmp stdio \
-device virtio-scsi-pci,bus=pci.0 -drive \
id=drive_image2,if=none,format=raw,file=file2,bps=512000,iops=100,group=foo \
-device scsi-hd,id=image2,drive=drive_image2 -drive \
id=drive_image3,if=none,format=raw,file=file3,bps=512000,iops=100,group=foo \
-device scsi-hd,id=image3,drive=drive_image3
{'execute':'qmp_capabilities'}
{'execute':'device_del','arguments':{'id':'image3'}}
{'execute':'system_reset'}
Quoted 7 lines
Fixes https://bugzilla.redhat.com/show_bug.cgi?id=1428810
Suggested-by Alberto Garcia <[email protected]>
Signed-off-by Eric Blake <[email protected]>
---
 block/block-backend.c | 3 +++
 1 file changed, 3 insertions(+)
Reviewed-by Stefan Hajnoczi <[email protected]>