From f7281c6cb9bbf3e5757adf52a7820499b5a7483b Mon Sep 17 00:00:00 2001 From: Nicolas Lacasse Date: Fri, 27 Aug 2021 13:09:28 -0700 Subject: Fix lock order violations: mm.mappingMu > Task.mu. Document this ordering in mm/mm.go. PiperOrigin-RevId: 393413203 --- pkg/sentry/kernel/task_exit.go | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) (limited to 'pkg/sentry/kernel/task_exit.go') diff --git a/pkg/sentry/kernel/task_exit.go b/pkg/sentry/kernel/task_exit.go index 342e5debe..b3931445b 100644 --- a/pkg/sentry/kernel/task_exit.go +++ b/pkg/sentry/kernel/task_exit.go @@ -230,9 +230,16 @@ func (*runExitMain) execute(t *Task) taskRunState { t.tg.pidns.owner.mu.Lock() t.updateRSSLocked() t.tg.pidns.owner.mu.Unlock() + + // Release the task image resources. Accessing these fields must be + // done with t.mu held, but the mm.DecUsers() call must be done outside + // of that lock. t.mu.Lock() - t.image.release() + mm := t.image.MemoryManager + t.image.MemoryManager = nil + t.image.fu = nil t.mu.Unlock() + mm.DecUsers(t) // Releasing the MM unblocks a blocked CLONE_VFORK parent. t.unstopVforkParent() -- cgit v1.2.3