Re: [libvirt] [PATCH v2] storage: Resolve storage driver crash

Resolve a storage driver crash as a result of a long running storageVolCreateXML when the virStorageVolPoolRefreshThread is run as a result of when a storageVolUpload completed and ran the virStoragePoolObjClearVols without checking if the creation code was currently processing a buildVol after incrementing the driver->asyncjob count. The refreshThread will now check the pool asyncjob count before attempting to pursue the pool refresh. Adjust the documentation to describe the condition. Crash from valgrind is as follows (with a bit of editing): ==21309== Invalid read of size 8 ==21309== at 0x153E47AF: storageBackendUpdateVolTargetInfo ==21309== by 0x153E4C30: virStorageBackendUpdateVolInfo ==21309== by 0x153E52DE: virStorageBackendVolRefreshLocal ==21309== by 0x153DE29E: storageVolCreateXML ==21309== by 0x562035B: virStorageVolCreateXML ==21309== by 0x147366: remoteDispatchStorageVolCreateXML ... ==21309== Address 0x2590a720 is 64 bytes inside a block of size 336 free'd ==21309== at 0x4C2F2BB: free ==21309== by 0x54CB9FA: virFree ==21309== by 0x55BC800: virStorageVolDefFree ==21309== by 0x55BF1D8: virStoragePoolObjClearVols ==21309== by 0x153D967E: virStorageVolPoolRefreshThread ... ==21309== Block was alloc'd at ==21309== at 0x4C300A5: calloc ==21309== by 0x54CB483: virAlloc ==21309== by 0x55BDC1F: virStorageVolDefParseXML ==21309== by 0x55BDC1F: virStorageVolDefParseNode ==21309== by 0x55BE5A4: virStorageVolDefParse ==21309== by 0x153DDFF1: storageVolCreateXML ==21309== by 0x562035B: virStorageVolCreateXML ==21309== by 0x147366: remoteDispatchStorageVolCreateXML ... Signed-off-by: John Ferlan <jferlan(a)redhat.com&gt; --- v1: https://www.redhat.com/archives/libvir-list/2017-November/msg00198.html Changes since v1: - From review, remove the retry if Asyncjobs > 0 logic and replace with a VIR_DEBUG indicating not doing refresh due to Asyncjob running and just goto cleanup. - Adjust the virStorageVolUpload docs to note that an attempt will be made to refresh the pool. - Drop patch 2 which added the Asyncjobs > 0 check to the SCSI pool refresh thread. Since a SCSI pool doesn't support buildVol, the asyncjob count cannot be anything other than zero, so it's pointless. src/libvirt-storage.c | 3 ++- src/storage/storage_driver.c | 7 +++++++ 2 files changed, 9 insertions(+), 1 deletion(-)