Fix misuses of kernel.Task as context.Context.

kernel.Task can only be used as context.Context by that Task's task goroutine.
This is violated in at least two places:

- In any case where one thread accesses the /proc/[tid] of any other thread,
  passing the kernel.Task for [tid] as the context.Context is incorrect.

- Task.rebuildTraceContext() may be called by Kernel.RebuildTraceContexts()
  outside the scope of any task goroutine.

Fix these (as well as a data race on Task.traceContext discovered during the
course of finding the latter).

PiperOrigin-RevId: 342174404

1 files changed, 3 insertions, 3 deletions

diff --git a/pkg/sentry/fsimpl/proc/subtasks.go b/pkg/sentry/fsimpl/proc/subtasks.go
index e001d5032..c53cc0122 100644
--- a/pkg/sentry/fsimpl/proc/subtasks.go
+++ b/pkg/sentry/fsimpl/proc/subtasks.go
@@ -50,7 +50,7 @@ type subtasksInode struct {
 
 var _ kernfs.Inode = (*subtasksInode)(nil)
 
-func (fs *filesystem) newSubtasks(task *kernel.Task, pidns *kernel.PIDNamespace, cgroupControllers map[string]string) kernfs.Inode {
+func (fs *filesystem) newSubtasks(ctx context.Context, task *kernel.Task, pidns *kernel.PIDNamespace, cgroupControllers map[string]string) kernfs.Inode {
 	subInode := &subtasksInode{
 		fs:                fs,
 		task:              task,
@@ -58,7 +58,7 @@ func (fs *filesystem) newSubtasks(task *kernel.Task, pidns *kernel.PIDNamespace,
 		cgroupControllers: cgroupControllers,
 	}
 	// Note: credentials are overridden by taskOwnedInode.
-	subInode.InodeAttrs.Init(task, task.Credentials(), linux.UNNAMED_MAJOR, fs.devMinor, fs.NextIno(), linux.ModeDirectory|0555)
+	subInode.InodeAttrs.Init(ctx, task.Credentials(), linux.UNNAMED_MAJOR, fs.devMinor, fs.NextIno(), linux.ModeDirectory|0555)
 	subInode.OrderedChildren.Init(kernfs.OrderedChildrenOptions{})
 	subInode.InitRefs()
 
@@ -80,7 +80,7 @@ func (i *subtasksInode) Lookup(ctx context.Context, name string) (kernfs.Inode,
 	if subTask.ThreadGroup() != i.task.ThreadGroup() {
 		return nil, syserror.ENOENT
 	}
-	return i.fs.newTaskInode(subTask, i.pidns, false, i.cgroupControllers)
+	return i.fs.newTaskInode(ctx, subTask, i.pidns, false, i.cgroupControllers)
 }
 
 // IterDirents implements kernfs.inodeDirectory.IterDirents.