| Message ID | 20240301171143.809835-6-vsementsov@yandex-team.ru |
|---|---|
| State | New |
| Headers | show |
| Series | vhost-user-blk: live resize additional APIs | expand |
Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> writes: > Command result is racy if allow it during migration. Let's allow the > sync only in RUNNING state. > > Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> If I understand this correctly, the previous commit introduces a race, and this one fixes it. We normally avoid such temporary bugs. When avoidance is impractical, we point them out in commit message and FIXME comment. > --- > include/sysemu/runstate.h | 1 + > system/qdev-monitor.c | 27 ++++++++++++++++++++++++++- > system/runstate.c | 5 +++++ > 3 files changed, 32 insertions(+), 1 deletion(-) > > diff --git a/include/sysemu/runstate.h b/include/sysemu/runstate.h > index 0117d243c4..296af52322 100644 > --- a/include/sysemu/runstate.h > +++ b/include/sysemu/runstate.h > @@ -5,6 +5,7 @@ > #include "qemu/notify.h" > > bool runstate_check(RunState state); > +const char *current_run_state_str(void); > void runstate_set(RunState new_state); > RunState runstate_get(void); > bool runstate_is_running(void); > diff --git a/system/qdev-monitor.c b/system/qdev-monitor.c > index e3107a12d7..b83b5d23c9 100644 > --- a/system/qdev-monitor.c > +++ b/system/qdev-monitor.c > @@ -23,6 +23,7 @@ > #include "monitor/monitor.h" > #include "monitor/qdev.h" > #include "sysemu/arch_init.h" > +#include "sysemu/runstate.h" > #include "qapi/error.h" > #include "qapi/qapi-commands-qdev.h" > #include "qapi/qmp/dispatch.h" > @@ -983,7 +984,31 @@ int qdev_sync_config(DeviceState *dev, Error **errp) > > void qmp_device_sync_config(const char *id, Error **errp) > { > - DeviceState *dev = find_device_state(id, true, errp); > + MigrationState *s = migrate_get_current(); > + DeviceState *dev; > + > + /* > + * During migration there is a race between syncing`config and migrating it, > + * so let's just not allow it. > + * > + * Moreover, let's not rely on setting up interrupts in paused state, which > + * may be a part of migration process. Wrap your comment lines around column 70, please. > + */ > + > + if (migration_is_running(s->state)) { > + error_setg(errp, "Config synchronization is not allowed " > + "during migration."); > + return; > + } > + > + if (!runstate_is_running()) { > + error_setg(errp, "Config synchronization allowed only in '%s' state, " > + "current state is '%s'", RunState_str(RUN_STATE_RUNNING), > + current_run_state_str()); > + return; > + } > + > + dev = find_device_state(id, true, errp); > if (!dev) { > return; > } > diff --git a/system/runstate.c b/system/runstate.c > index d6ab860eca..8fd89172ae 100644 > --- a/system/runstate.c > +++ b/system/runstate.c > @@ -189,6 +189,11 @@ bool runstate_check(RunState state) > return current_run_state == state; > } > > +const char *current_run_state_str(void) > +{ > + return RunState_str(current_run_state); > +} > + > static void runstate_init(void) > { > const RunStateTransition *p;
On 07.03.24 12:57, Markus Armbruster wrote: > Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> writes: > >> Command result is racy if allow it during migration. Let's allow the >> sync only in RUNNING state. >> >> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> > > If I understand this correctly, the previous commit introduces a race, > and this one fixes it. Sure, I will merge it. I recently argued against such things, bad for me to break the rule myself) > > We normally avoid such temporary bugs. When avoidance is impractical, > we point them out in commit message and FIXME comment. > >> --- >> include/sysemu/runstate.h | 1 + >> system/qdev-monitor.c | 27 ++++++++++++++++++++++++++- >> system/runstate.c | 5 +++++ >> 3 files changed, 32 insertions(+), 1 deletion(-) >> >> diff --git a/include/sysemu/runstate.h b/include/sysemu/runstate.h >> index 0117d243c4..296af52322 100644 >> --- a/include/sysemu/runstate.h >> +++ b/include/sysemu/runstate.h >> @@ -5,6 +5,7 @@ >> #include "qemu/notify.h" >> >> bool runstate_check(RunState state); >> +const char *current_run_state_str(void); >> void runstate_set(RunState new_state); >> RunState runstate_get(void); >> bool runstate_is_running(void); >> diff --git a/system/qdev-monitor.c b/system/qdev-monitor.c >> index e3107a12d7..b83b5d23c9 100644 >> --- a/system/qdev-monitor.c >> +++ b/system/qdev-monitor.c >> @@ -23,6 +23,7 @@ >> #include "monitor/monitor.h" >> #include "monitor/qdev.h" >> #include "sysemu/arch_init.h" >> +#include "sysemu/runstate.h" >> #include "qapi/error.h" >> #include "qapi/qapi-commands-qdev.h" >> #include "qapi/qmp/dispatch.h" >> @@ -983,7 +984,31 @@ int qdev_sync_config(DeviceState *dev, Error **errp) >> >> void qmp_device_sync_config(const char *id, Error **errp) >> { >> - DeviceState *dev = find_device_state(id, true, errp); >> + MigrationState *s = migrate_get_current(); >> + DeviceState *dev; >> + >> + /* >> + * During migration there is a race between syncing`config and migrating it, >> + * so let's just not allow it. >> + * >> + * Moreover, let's not rely on setting up interrupts in paused state, which >> + * may be a part of migration process. > > Wrap your comment lines around column 70, please. OK. I never remember this recommendation.. Probably we'd better have a check in checkpatch for it > >> + */ >> + >> + if (migration_is_running(s->state)) { >> + error_setg(errp, "Config synchronization is not allowed " >> + "during migration."); >> + return; >> + } >> + >> + if (!runstate_is_running()) { >> + error_setg(errp, "Config synchronization allowed only in '%s' state, " >> + "current state is '%s'", RunState_str(RUN_STATE_RUNNING), >> + current_run_state_str()); >> + return; >> + } >> + >> + dev = find_device_state(id, true, errp); >> if (!dev) { >> return; >> } >> diff --git a/system/runstate.c b/system/runstate.c >> index d6ab860eca..8fd89172ae 100644 >> --- a/system/runstate.c >> +++ b/system/runstate.c >> @@ -189,6 +189,11 @@ bool runstate_check(RunState state) >> return current_run_state == state; >> } >> >> +const char *current_run_state_str(void) >> +{ >> + return RunState_str(current_run_state); >> +} >> + >> static void runstate_init(void) >> { >> const RunStateTransition *p; >
diff --git a/include/sysemu/runstate.h b/include/sysemu/runstate.h index 0117d243c4..296af52322 100644 --- a/include/sysemu/runstate.h +++ b/include/sysemu/runstate.h @@ -5,6 +5,7 @@ #include "qemu/notify.h" bool runstate_check(RunState state); +const char *current_run_state_str(void); void runstate_set(RunState new_state); RunState runstate_get(void); bool runstate_is_running(void); diff --git a/system/qdev-monitor.c b/system/qdev-monitor.c index e3107a12d7..b83b5d23c9 100644 --- a/system/qdev-monitor.c +++ b/system/qdev-monitor.c @@ -23,6 +23,7 @@ #include "monitor/monitor.h" #include "monitor/qdev.h" #include "sysemu/arch_init.h" +#include "sysemu/runstate.h" #include "qapi/error.h" #include "qapi/qapi-commands-qdev.h" #include "qapi/qmp/dispatch.h" @@ -983,7 +984,31 @@ int qdev_sync_config(DeviceState *dev, Error **errp) void qmp_device_sync_config(const char *id, Error **errp) { - DeviceState *dev = find_device_state(id, true, errp); + MigrationState *s = migrate_get_current(); + DeviceState *dev; + + /* + * During migration there is a race between syncing`config and migrating it, + * so let's just not allow it. + * + * Moreover, let's not rely on setting up interrupts in paused state, which + * may be a part of migration process. + */ + + if (migration_is_running(s->state)) { + error_setg(errp, "Config synchronization is not allowed " + "during migration."); + return; + } + + if (!runstate_is_running()) { + error_setg(errp, "Config synchronization allowed only in '%s' state, " + "current state is '%s'", RunState_str(RUN_STATE_RUNNING), + current_run_state_str()); + return; + } + + dev = find_device_state(id, true, errp); if (!dev) { return; } diff --git a/system/runstate.c b/system/runstate.c index d6ab860eca..8fd89172ae 100644 --- a/system/runstate.c +++ b/system/runstate.c @@ -189,6 +189,11 @@ bool runstate_check(RunState state) return current_run_state == state; } +const char *current_run_state_str(void) +{ + return RunState_str(current_run_state); +} + static void runstate_init(void) { const RunStateTransition *p;
Command result is racy if allow it during migration. Let's allow the sync only in RUNNING state. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> --- include/sysemu/runstate.h | 1 + system/qdev-monitor.c | 27 ++++++++++++++++++++++++++- system/runstate.c | 5 +++++ 3 files changed, 32 insertions(+), 1 deletion(-)