On 3/7/24 10:33, Dominik Csapak wrote: > when triggering a vm reboot from the host (via cli/api), the reboot code > is called under a guest lock, which creates a reboot request, shuts down > the vm and calls the regular cleanup code (which includes the mdev > cleanup). > > in parallel the qmeventd sees the vanished vm, and starts 'qm cleanup' > which is (among other tasks) used to restart a vm with a pending reboot > request. It does this also under a guest lock, with a default timeout of > 10 seconds. > > Since we currently wait 10 seconds for the nvidia driver to clean the > mdev, this creates a race condition for the cleanup lock. Iow. when the > call to `qm cleanup` starts before we started to sleep for 10 seconds, > it will not be able to acquire its lock and not start the vm again. > > To fix it, do two things: > * increase the timeout in `qm cleanup` to 60 seconds > (technically this still might run into a timeout, as we can configure > up to 16 mediated devices with up to 10 seconds sleep each, but > realistically most users won't configure more than two or three of > them, if even that) > > * change the `sleep 10` to a loop sleeping for 1 second each before > checking the state again. This shortens the timeout when the driver > can clean it up in the meantime. > > Further, add a bit of logging, so we can properly see in the (task) log > what is happening when. > > Fixes: 49c51a60 (pci: workaround nvidia driver issue on mdev cleanup) > Signed-off-by: Dominik Csapak <d.csa...@proxmox.com> > --- > PVE/CLI/qm.pm | 3 ++- > PVE/QemuServer.pm | 16 ++++++++++++---- > 2 files changed, 14 insertions(+), 5 deletions(-) > > diff --git a/PVE/CLI/qm.pm b/PVE/CLI/qm.pm > index b17b4fe2..dce6c7a1 100755 > --- a/PVE/CLI/qm.pm > +++ b/PVE/CLI/qm.pm > @@ -915,7 +915,8 @@ __PACKAGE__->register_method({ > my $storecfg = PVE::Storage::config(); > warn "Starting cleanup for $vmid\n"; > > - PVE::QemuConfig->lock_config($vmid, sub { > + # mdev cleanup can take a while, so wait up to 60 seconds > + PVE::QemuConfig->lock_config_full($vmid, 60, sub { > my $conf = PVE::QemuConfig->load_config ($vmid); > my $pid = PVE::QemuServer::check_running ($vmid); > die "vm still running\n" if $pid; > diff --git a/PVE/QemuServer.pm b/PVE/QemuServer.pm > index b45507aa..efe93c62 100644 > --- a/PVE/QemuServer.pm > +++ b/PVE/QemuServer.pm > @@ -6133,12 +6133,20 @@ sub cleanup_pci_devices { > my $dev_sysfs_dir = "/sys/bus/mdev/devices/$uuid"; > > # some nvidia vgpu driver versions want to clean the mdevs up > themselves, and error > - # out when we do it first. so wait for 10 seconds and then try it > - if ($d->{ids}->[0]->[0]->{vendor} =~ m/^(0x)?10de$/) { > - sleep 10; > + # out when we do it first. so wait for up to 10 seconds and then > try it manually > + if ($d->{ids}->[0]->[0]->{vendor} =~ m/^(0x)?10de$/ && -e > $dev_sysfs_dir) { > + my $count = 0; > + while (-e $dev_sysfs_dir && $count < 10) { > + sleep 1; > + $count++; > + } > + warn "waited $count seconds for mdev cleanup\n"; > } > > - PVE::SysFSTools::file_write("$dev_sysfs_dir/remove", "1") if -e > $dev_sysfs_dir; > + if (-e $dev_sysfs_dir) { > + warn "cleaning up mediated device $uuid\n"; > + PVE::SysFSTools::file_write("$dev_sysfs_dir/remove", "1"); > + } > } > } > PVE::QemuServer::PCI::remove_pci_reservation($vmid);
lgtm Reviewed-by: Mira Limbeck <m.limb...@proxmox.com> Sadly I can't test it since I don't have a vGPU-capable nvidia card. But the customer who reported it has tested the patch already and it seemed to fix the issue without introducing other issues so far. _______________________________________________ pve-devel mailing list pve-devel@lists.proxmox.com https://lists.proxmox.com/cgi-bin/mailman/listinfo/pve-devel