Re: [libvirt] [PATCH 1/3] qemu: Handle EEXIST gracefully in qemuDomainCreateDevice

https://bugzilla.redhat.com/show_bug.cgi?id=1406837 Imagine you have a domain configured in such way that you are assigning two PCI devices that fall into the same IOMMU group. With mount namespace enabled what happens is that for the first PCI device corresponding /dev/vfio/X entry is created and when the code tries to do the same for the second mknod() fails as /dev/vfio/X already exists: 2016-12-21 14:40:45.648+0000: 24681: error : qemuProcessReportLogError:1792 : internal error: Process exited prior to exec: libvirt: QEMU Driver error : Failed to make device /var/run/libvirt/qemu/windoze.dev//vfio/22: File exists Worse, by default there are some devices that are created in the namespace regardless of domain configuration (e.g. /dev/null, /dev/urandom, etc.). If one of them is set as backend for some guest device (e.g. rng, chardev, etc.) it's the same story as described above. Weirdly, in attach code this is already handled. Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com&gt; --- src/qemu/qemu_domain.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c index 25cb4ad590..d05ebcb416 100644 --- a/src/qemu/qemu_domain.c +++ b/src/qemu/qemu_domain.c @@ -6957,10 +6957,12 @@ qemuDomainCreateDevice(const char *device, } if (mknod(devicePath, sb.st_mode, sb.st_rdev) < 0) { - virReportSystemError(errno, - _("Failed to make device %s"), - devicePath); - goto cleanup; + if (errno != EEXIST) { + virReportSystemError(errno, + _("Failed to make device %s"), + devicePath); + goto cleanup; + } }

if (chown(devicePath, sb.st_uid, sb.st_gid) < 0) { -- 2.11.0 -- libvir-list mailing list libvir-list(a)redhat.com https://www.redhat.com/mailman/listinfo/libvir-list