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1. famerico commented on Nov 10, 2026

   

   famerico

   on Nov 10, 2026

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   We found the root cause by reading the code on tag 4.22.1.1, and it is narrower than the title of this issue suggests.

   KVMStoragePoolManager.disconnectPhysicalDiskByPath(path) passes the local path of every disk of the VM to every registered adaptor. IscsiAdmStorageAdaptor.disconnectPhysicalDiskByPath only skips a path if it does not contain -iscsi-:

   String search1 = "/dev/disk/by-path/ip-";
   ...
   if (!localPath.contains(search3)) {   // search3 = "-iscsi-"
       return false;
   }
   int index = localPath.indexOf(search2);   // search2 = ":"
   String host = localPath.substring(search1.length(), index);

   It then assumes a path shaped like /dev/disk/by-path/ip-<host>:<port>-iscsi-<iqn>-lun-<n>.

   In our setup the disk of the SharedMountPoint pool is /mnt/<pool dir>/<uuid>, and the pool directory name contains -iscsi-. The path is 58 characters long, passes the contains("-iscsi-") check and has no :. indexOf(":") returns -1 and search1.length() is 21, which gives exactly the observed Range [21, -1) out of bounds for length 58.

   So the trigger is a mount path containing -iscsi-, not the storage being iSCSI-backed. A SharedMountPoint pool whose directory name does not contain that string should not hit this. We have not run that variant yet.

   Suggested fix: guard on the expected prefix (localPath.startsWith(search1)) and check that the indexOf results are not -1 before calling substring, returning false otherwise.

   Why the second Stop works is still not verified. Our hypothesis is that the first attempt already stops the domain and fails only in cleanupDisk, and the retry finds the VM stopped and does not run the cleanup again.
2. famerico

   changed the title [-][KVM] StringIndexOutOfBoundsException in IscsiAdmStorageAdaptor.disconnectPhysicalDiskByPath makes the first Stop VM fail when a SharedMountPoint/iSCSI volume is attached[/-] [+][KVM] StringIndexOutOfBoundsException in IscsiAdmStorageAdaptor.disconnectPhysicalDiskByPath makes the first Stop VM fail when a disk path contains "-iscsi-" (e.g. a SharedMountPoint pool mount directory)[/+] on Nov 10, 2026
3. famerico commented on Nov 10, 2026

   

   famerico

   on Nov 10, 2026

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   Additional confirmation of the root cause from a controlled test on our lab (CloudStack 4.22.1.1, KVM):

   • Same filesystem (same multipath device, same files and UUIDs) bind-mounted at /mnt/block-primary (no -iscsi- in the name) and registered as a new SharedMountPoint primary storage.
   • A volume was created in that pool and attached to a test VM.
   • Stop Instance succeeded on the first attempt, with no exception (Running -> Stopping -> Stopped, no retry).
   • With the original mount directory /mnt/fa-iscsi-primary, the first Stop failed every time with Range [21, -1) out of bounds for length 58.

   This matches the code analysis above: the only variable that changed is the mount directory name, so the trigger is the -iscsi- substring in the disk path, not the pool type.

   Not tested: VM migration and volume detach, which also call cleanupDisk (LibvirtMigrateCommandWrapper, KVMStorageProcessor). Our lab has no spare hosts, so they may be affected in the same way.
4. DaanHoogland

   added this to the 4.22.3 milestone on Nov 11, 2026
5. github-actions commented on Nov 11, 2026

   

   github-actionsBot

   on Nov 11, 2026 – with GitHub Actions

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   🎯 Triage report

   On KVM, the first Stop of a VM with a disk on a SharedMountPoint pool fails with a StringIndexOutOfBoundsException in IscsiAdmStorageAdaptor.disconnectPhysicalDiskByPath. The method checks only that the path contains -iscsi-, then assumes the /dev/disk/by-path/ip-...:port-iscsi-... shape. A mount directory containing -iscsi- passes that check, and indexOf(":") returns -1. The reporter's lab confirmed that the same storage mounted at a directory without -iscsi- stops on the first attempt.

   📊 Assessment

   Dimension	Value	Reasoning
   Type	type:bug	Unguarded substring on an unexpected path shape
   Component	component:kvm	Thrown in the KVM agent's iSCSI storage adaptor
   Severity	Severity:Minor	Stop fails once, and the retry succeeds
   Labels	type:bug, component:kvm, Severity:Minor
   Coding agent	Suitable	The guard is specified: check the prefix and indexOf results, return false otherwise

   🔗 Similar issues

   • [KVM] Encrypted volume on SharedMountPoint pool is created without LUKS and attach fails with "No encryption in image header" #14663 (related) — SharedMountPoint pool on KVM with encryption; same pool type

   💡 Notes and suggestions

   • Reproduction: mount an iSCSI-backed SharedMountPoint under a directory that contains -iscsi-, attach a data volume, then stop the VM.
   • The reporter's hypothesis for why the second stop works (the domain is already stopped) is not verified.
   • Migration and volume detach also call cleanupDisk; check them with the same guard.

   Generated by Daily Issue Triage · copilot · haiku55 · ~6 AIC · ⊞ 3.8K · ◷

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