diff options
| author | Dean Deng <deandeng@google.com> | 2020-07-23 16:22:41 -0700 |
|---|---|---|
| committer | gVisor bot <gvisor-bot@google.com> | 2020-07-23 16:25:34 -0700 |
| commit | 8fed97794edcbaa7069dbd39604030e4fbb6891c (patch) | |
| tree | 2bfacd76be57fd91a279f256c35c73ba640db164 /pkg/sentry/kernel/task.go | |
| parent | 3a2fac0ab9e24382c8e19e6cf8170ba01e78930c (diff) | |
Add task work mechanism.
Like task_work in Linux, this allows us to register callbacks to be executed
before returning to userspace. This is needed for kcov support, which requires
coverage information to be up-to-date whenever we are in user mode. We will
provide coverage data through the kcov interface to enable coverage-directed
fuzzing in syzkaller.
One difference from Linux is that task work cannot queue work before the
transition to userspace that it precedes; queued work will be picked up before
the next transition.
PiperOrigin-RevId: 322889984
Diffstat (limited to 'pkg/sentry/kernel/task.go')
| -rw-r--r-- | pkg/sentry/kernel/task.go | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/pkg/sentry/kernel/task.go b/pkg/sentry/kernel/task.go index f48247c94..b3d655b6e 100644 --- a/pkg/sentry/kernel/task.go +++ b/pkg/sentry/kernel/task.go @@ -68,6 +68,21 @@ type Task struct { // runState is exclusive to the task goroutine. runState taskRunState + // taskWorkCount represents the current size of the task work queue. It is + // used to avoid acquiring taskWorkMu when the queue is empty. + // + // Must accessed with atomic memory operations. + taskWorkCount int32 + + // taskWorkMu protects taskWork. + taskWorkMu sync.Mutex `state:"nosave"` + + // taskWork is a queue of work to be executed before resuming user execution. + // It is similar to the task_work mechanism in Linux. + // + // taskWork is exclusive to the task goroutine. + taskWork []TaskWorker + // haveSyscallReturn is true if tc.Arch().Return() represents a value // returned by a syscall (or set by ptrace after a syscall). // |