diff options
Diffstat (limited to 'pkg/sentry/kernel/sessions.go')
| -rw-r--r-- | pkg/sentry/kernel/sessions.go | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/pkg/sentry/kernel/sessions.go b/pkg/sentry/kernel/sessions.go index e5f297478..047b5214d 100644 --- a/pkg/sentry/kernel/sessions.go +++ b/pkg/sentry/kernel/sessions.go @@ -328,8 +328,14 @@ func (tg *ThreadGroup) createSession() error { childTG.processGroup.incRefWithParent(pg) childTG.processGroup.decRefWithParent(oldParentPG) }) - tg.processGroup.decRefWithParent(oldParentPG) + // If tg.processGroup is an orphan, decRefWithParent will lock + // the signal mutex of each thread group in tg.processGroup. + // However, tg's signal mutex may already be locked at this + // point. We change tg's process group before calling + // decRefWithParent to avoid locking tg's signal mutex twice. + oldPG := tg.processGroup tg.processGroup = pg + oldPG.decRefWithParent(oldParentPG) } else { // The current process group may be nil only in the case of an // unparented thread group (i.e. the init process). This would |