[libvirt] udevadm settle can take too long

Hi, http://bugs.debian.org/663931 is a bug I'm hitting, where virt-manager times out on the initial connection to libvirt. The basic problem is that, while checking storage volumes, virt-manager causes libvirt to call "udevadm settle". There's an interaction where libvirt's earlier use of network namespaces (to probe LXC features) had caused some uevents to be sent that get filtered out before they reach udev. This confuses "udevadm settle" a bit, and so it sits there waiting for a 2-3 minute built-in timeout before returning. Eventually libvirtd prints: 2012-04-22 18:22:18.678+0000: 30503: warning : virKeepAliveTimer:182 : No response from client 0x7feec4003630 after 5 keepalive messages in 30 seconds and virt-manager prints: 2012-04-22 18:22:18.931+0000: 30647: warning : virKeepAliveSend:128 : Failed to send keepalive response to client 0x25004e0 and the connection gets dropped. One workaround could be to specify a shorter timeout when doing the settle. The patch appended below allows virt-manager to work, although the connection still has to wait for the 10 second timeout before it succeeds. I don't know what a better solution would be, though. It seems the udevadm behavior might not be considered a bug from the udev/kernel point of view: https://lkml.org/lkml/2012/4/22/60 I'm using Linux 3.2.14 with libvirt 0.9.11. You can trigger the udevadm issue using a program I posted at the Debian bug report link above. -jim From: Jim Paris <jim(a)jtan.com&gt; Date: Sun, 22 Apr 2012 14:35:47 -0400 Subject: [PATCH] shorten udevadmin settle timeout Otherwise, udevadmin settle can take so long that connections from e.g. virt-manager will get closed. --- src/util/util.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) diff --git a/src/util/util.c b/src/util/util.c index 6e041d6..dfe458e 100644 --- a/src/util/util.c +++ b/src/util/util.c @@ -2593,9 +2593,9 @@ virFileFindMountPoint(const char *type ATTRIBUTE_UNUSED) void virFileWaitForDevices(void) { # ifdef UDEVADM - const char *const settleprog[] = { UDEVADM, "settle", NULL }; + const char *const settleprog[] = { UDEVADM, "settle", "--timeout", "10", NULL }; # else - const char *const settleprog[] = { UDEVSETTLE, NULL }; + const char *const settleprog[] = { UDEVSETTLE, "--timeout", "10", NULL }; # endif int exitstatus; -- 1.7.7