[libvirt PATCH] check for NULL before calling g_regex_unref
g_regex_unref reports an error if called with a NULL argument. We have two cases in the code where we (possibly) call it on a NULL argument. The interesting one is in virDomainQemuMonitorEventCleanup. Based on VIR_CONNECT_DOMAIN_QEMU_MONITOR_EVENT_REGISTER_REGEX, we unref data->regex, which has two problems: * On the client side, flags is -1 so the comparison is true even if no regex was used, reproducible by: $ virsh qemu-monitor-event --timeout 1 which results in an ugly error: (process:1289846): GLib-CRITICAL **: 14:58:42.631: g_regex_unref: assertion 'regex != NULL' failed * On the server side, we only create the regex if both the flag and the string are present, so it's possible to trigger this message by: $ virsh qemu-monitor-event --regex --timeout 1 Use a non-NULL comparison instead of the flag to decide whether we need to unref the regex. Signed-off-by: Ján Tomko <jtomko@redhat.com> Fixes: 71efb59a4de7c51b1bc889a316f1796ebf55738f https://bugzilla.redhat.com/show_bug.cgi?id=1861176 --- src/conf/domain_event.c | 2 +- tests/vboxsnapshotxmltest.c | 3 ++- 2 files changed, 3 insertions(+), 2 deletions(-) diff --git a/src/conf/domain_event.c b/src/conf/domain_event.c index 33fbf10406..d3acde0236 100644 --- a/src/conf/domain_event.c +++ b/src/conf/domain_event.c @@ -2194,7 +2194,7 @@ virDomainQemuMonitorEventCleanup(void *opaque) virDomainQemuMonitorEventData *data = opaque; VIR_FREE(data->event); - if (data->flags & VIR_CONNECT_DOMAIN_QEMU_MONITOR_EVENT_REGISTER_REGEX) + if (data->regex) g_regex_unref(data->regex); if (data->freecb) (data->freecb)(data->opaque); diff --git a/tests/vboxsnapshotxmltest.c b/tests/vboxsnapshotxmltest.c index 7e3f85cc58..d2beb7858d 100644 --- a/tests/vboxsnapshotxmltest.c +++ b/tests/vboxsnapshotxmltest.c @@ -135,7 +135,8 @@ mymain(void) DO_TEST("2disks-3snap-brother"); cleanup: - g_regex_unref(testSnapshotXMLVariableLineRegex); + if (testSnapshotXMLVariableLineRegex) + g_regex_unref(testSnapshotXMLVariableLineRegex); return ret == 0 ? EXIT_SUCCESS : EXIT_FAILURE; } -- 2.26.2
On Tue, Sep 08, 2020 at 15:20:52 +0200, Ján Tomko wrote:
g_regex_unref reports an error if called with a NULL argument.
We have two cases in the code where we (possibly) call it on a NULL argument. The interesting one is in virDomainQemuMonitorEventCleanup.
Based on VIR_CONNECT_DOMAIN_QEMU_MONITOR_EVENT_REGISTER_REGEX, we unref data->regex, which has two problems:
* On the client side, flags is -1 so the comparison is true even if no regex was used, reproducible by: $ virsh qemu-monitor-event --timeout 1 which results in an ugly error: (process:1289846): GLib-CRITICAL **: 14:58:42.631: g_regex_unref: assertion 'regex != NULL' failed * On the server side, we only create the regex if both the flag and the string are present, so it's possible to trigger this message by: $ virsh qemu-monitor-event --regex --timeout 1
Use a non-NULL comparison instead of the flag to decide whether we need to unref the regex.
Please modify this last sentence to describe both fixes. I've flushed out that there's another case by the time I've read the end here.
Signed-off-by: Ján Tomko <jtomko@redhat.com> Fixes: 71efb59a4de7c51b1bc889a316f1796ebf55738f https://bugzilla.redhat.com/show_bug.cgi?id=1861176 --- src/conf/domain_event.c | 2 +- tests/vboxsnapshotxmltest.c | 3 ++- 2 files changed, 3 insertions(+), 2 deletions(-)
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
On Tue, Sep 08, 2020 at 03:20:52PM +0200, Ján Tomko wrote:
g_regex_unref reports an error if called with a NULL argument.
We have two cases in the code where we (possibly) call it on a NULL argument. The interesting one is in virDomainQemuMonitorEventCleanup.
Based on VIR_CONNECT_DOMAIN_QEMU_MONITOR_EVENT_REGISTER_REGEX, we unref data->regex, which has two problems:
* On the client side, flags is -1 so the comparison is true even if no regex was used, reproducible by: $ virsh qemu-monitor-event --timeout 1 which results in an ugly error: (process:1289846): GLib-CRITICAL **: 14:58:42.631: g_regex_unref: assertion 'regex != NULL' failed * On the server side, we only create the regex if both the flag and the string are present, so it's possible to trigger this message by: $ virsh qemu-monitor-event --regex --timeout 1
Use a non-NULL comparison instead of the flag to decide whether we need to unref the regex.
Signed-off-by: Ján Tomko <jtomko@redhat.com> Fixes: 71efb59a4de7c51b1bc889a316f1796ebf55738f https://bugzilla.redhat.com/show_bug.cgi?id=1861176
Reviewed-by: Martin Kletzander <mkletzan@redhat.com> Any reason why regex_unref does not accept NULLs? It caught a misuse in the first case, but the second one could just make the code cleaner. Maybe we could create our own auto type over it? =D
participants (3)
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Ján Tomko -
Martin Kletzander -
Peter Krempa