https://bugzilla.redhat.com/show_bug.cgi?id=1591561 For reasons I don't understand my original patch of 75f0fd51124 freed not only the chardev from domain but also the one from passed virDomainDeviceDefPtr. This caused no troubles until now, because those two pointers were separate, but after I've introduced virDomainDetachDeviceAlias() they became the same resulting in double free on detach. Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com&gt; --- src/qemu/qemu_driver.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c index 42069ee617..7fe86d4d2e 100644 --- a/src/qemu/qemu_driver.c +++ b/src/qemu/qemu_driver.c @@ -8241,8 +8241,6 @@ qemuDomainDetachDeviceConfig(virDomainDefPtr vmdef, return -1; virDomainChrDefFree(chr); - virDomainChrDefFree(dev->data.chr); - dev->data.chr = NULL; break; case VIR_DOMAIN_DEVICE_FS: -- 2.16.4