https://bugzilla.redhat.com/show_bug.cgi?id=1367259 Crash occurs because 'secrets' is being dereferenced in call: if (qemuDomainSecretSetup(conn, priv, secinfo, disk->info.alias, VIR_SECRET_USAGE_TYPE_VOLUME, NULL, &src->encryption->secrets[0]->seclookupdef, true) < 0) (gdb) p *src->encryption $1 = {format = 2, nsecrets = 0, secrets = 0x0, encinfo = {cipher_size = 0, cipher_name = 0x0, cipher_mode = 0x0, cipher_hash = 0x0, ivgen_name = 0x0, ivgen_hash = 0x0}} (gdb) bt priv=priv@entry=0x7fffc03be160, disk=disk@entry=0x7fffb4002ae0) at qemu/qemu_domain.c:1087 disk=0x7fffb4002ae0, vm=0x7fffc03a2580, driver=0x7fffc02ca390, conn=0x7fffb00009a0) at qemu/qemu_hotplug.c:355 Upon entry to qemuDomainAttachVirtioDiskDevice, src->encryption points at a valid 'secret' buffer w/ nsecrets == 1; however, the call to qemuDomainDetermineDiskChain will call virStorageFileGetMetadata and eventually virStorageFileGetMetadataInternal where the src->encryption was overwritten when probing the volume. Commit id 'a48c7141' added code to virStorageFileGetMetadataInternal to determine if the disk/volume would use/need encryption and allocated a meta->encryption. This overwrote an existing encryption buffer already provided by the XML This patch adds a check for meta->encryption already present before just allocating and overwriting an existing buffer. It then checks the existing encryption data to ensure the XML provided format for the disk matches the expected format read from the disk and errors if there is a mismatch. Signed-off-by: John Ferlan <jferlan(a)redhat.com&gt; --- v1: http://www.redhat.com/archives/libvir-list/2016-August/msg00805.html Tested w/ delete luks volume, create luks volume, dump luks volume, attach to guest, detach from guest, and repeat... src/util/virstoragefile.c | 19 +++++++++++++++---- 1 file changed, 15 insertions(+), 4 deletions(-) diff --git a/src/util/virstoragefile.c b/src/util/virstoragefile.c index 471aa1f..feeb061 100644 --- a/src/util/virstoragefile.c +++ b/src/util/virstoragefile.c @@ -950,10 +950,21 @@ virStorageFileGetMetadataInternal(virStorageSourcePtr meta, for (i = 0; fileTypeInfo[meta->format].cryptInfo[i].format != 0; i++) { if (virStorageFileHasEncryptionFormat(&fileTypeInfo[meta->format].cryptInfo[i], buf, len)) { - if (VIR_ALLOC(meta->encryption) < 0) - goto cleanup; - - meta->encryption->format = fileTypeInfo[meta->format].cryptInfo[i].format; + int expt_fmt = fileTypeInfo[meta->format].cryptInfo[i].format; + if (!meta->encryption) { + if (VIR_ALLOC(meta->encryption) < 0) + goto cleanup; + + meta->encryption->format = expt_fmt; + } else { + if (meta->encryption->format != expt_fmt) { + virReportError(VIR_ERR_XML_ERROR, + _("encryption format %d doesn't match " + "expected format %d"), + meta->encryption->format, expt_fmt); + goto cleanup; + } + } } } } -- 2.7.4