[libvirt] [PATCH] Fix handling of VIR_EVENT_HANDLE_ERROR in QEMU monitor
Commit 4454a9efc728b91e791b1f14c26ea23a19d57f48 introduced bad behaviour on the VIR_EVENT_HANDLE_ERROR condition. This condition is only hit when an invalid FD is used in poll() (typically due to a double-close bug). The QEMU monitor code was treating this condition as non-fatal, and thus libvirt would poll() in a fast loop forever burning 100% CPU. VIR_EVENT_HANDLE_ERROR must be handled in the same way as VIR_EVENT_HANDLE_HANGUP, killing the QEMU instance. * src/qemu/qemu_monitor.c: Treat VIR_EVENT_HANDLE_ERROR as EOF --- src/qemu/qemu_monitor.c | 9 +++++---- 1 files changed, 5 insertions(+), 4 deletions(-) diff --git a/src/qemu/qemu_monitor.c b/src/qemu/qemu_monitor.c index 09a1b8e..26bb814 100644 --- a/src/qemu/qemu_monitor.c +++ b/src/qemu/qemu_monitor.c @@ -535,14 +535,14 @@ qemuMonitorIO(int watch, int fd, int events, void *opaque) { #endif if (mon->fd != fd || mon->watch != watch) { - if (events & VIR_EVENT_HANDLE_HANGUP) + if (events & (VIR_EVENT_HANDLE_HANGUP | VIR_EVENT_HANDLE_ERROR)) eof = true; qemuReportError(VIR_ERR_INTERNAL_ERROR, _("event from unexpected fd %d!=%d / watch %d!=%d"), mon->fd, fd, mon->watch, watch); error = true; } else if (mon->lastError.code != VIR_ERR_OK) { - if (events & VIR_EVENT_HANDLE_HANGUP) + if (events & (VIR_EVENT_HANDLE_HANGUP | VIR_EVENT_HANDLE_ERROR)) eof = true; error = true; } else { @@ -581,8 +581,9 @@ qemuMonitorIO(int watch, int fd, int events, void *opaque) { if (!error && !eof && events & VIR_EVENT_HANDLE_ERROR) { qemuReportError(VIR_ERR_INTERNAL_ERROR, - _("Error while waiting for monitor")); - error = 1; + _("Invalid file descriptor while waiting for monitor")); + eof = 1; + events &= ~VIR_EVENT_HANDLE_ERROR; } if (!error && events) { qemuReportError(VIR_ERR_INTERNAL_ERROR, -- 1.7.4.4
On Thu, Jun 02, 2011 at 11:52:10AM +0100, Daniel P. Berrange wrote:
Commit 4454a9efc728b91e791b1f14c26ea23a19d57f48 introduced bad behaviour on the VIR_EVENT_HANDLE_ERROR condition. This condition is only hit when an invalid FD is used in poll() (typically due to a double-close bug). The QEMU monitor code was treating this condition as non-fatal, and thus libvirt would poll() in a fast loop forever burning 100% CPU. VIR_EVENT_HANDLE_ERROR must be handled in the same way as VIR_EVENT_HANDLE_HANGUP, killing the QEMU instance.
* src/qemu/qemu_monitor.c: Treat VIR_EVENT_HANDLE_ERROR as EOF --- src/qemu/qemu_monitor.c | 9 +++++---- 1 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/src/qemu/qemu_monitor.c b/src/qemu/qemu_monitor.c index 09a1b8e..26bb814 100644 --- a/src/qemu/qemu_monitor.c +++ b/src/qemu/qemu_monitor.c @@ -535,14 +535,14 @@ qemuMonitorIO(int watch, int fd, int events, void *opaque) { #endif
if (mon->fd != fd || mon->watch != watch) { - if (events & VIR_EVENT_HANDLE_HANGUP) + if (events & (VIR_EVENT_HANDLE_HANGUP | VIR_EVENT_HANDLE_ERROR)) eof = true; qemuReportError(VIR_ERR_INTERNAL_ERROR, _("event from unexpected fd %d!=%d / watch %d!=%d"), mon->fd, fd, mon->watch, watch); error = true; } else if (mon->lastError.code != VIR_ERR_OK) { - if (events & VIR_EVENT_HANDLE_HANGUP) + if (events & (VIR_EVENT_HANDLE_HANGUP | VIR_EVENT_HANDLE_ERROR)) eof = true; error = true; } else { @@ -581,8 +581,9 @@ qemuMonitorIO(int watch, int fd, int events, void *opaque) { if (!error && !eof && events & VIR_EVENT_HANDLE_ERROR) { qemuReportError(VIR_ERR_INTERNAL_ERROR, - _("Error while waiting for monitor")); - error = 1; + _("Invalid file descriptor while waiting for monitor")); + eof = 1; + events &= ~VIR_EVENT_HANDLE_ERROR; } if (!error && events) { qemuReportError(VIR_ERR_INTERNAL_ERROR,
Hum, that serious ! ACK Daniel -- Daniel Veillard | libxml Gnome XML XSLT toolkit http://xmlsoft.org/ daniel@veillard.com | Rpmfind RPM search engine http://rpmfind.net/ http://veillard.com/ | virtualization library http://libvirt.org/
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Daniel P. Berrange -
Daniel Veillard