From c61d7761b42392d6c28ab6932707e0d3236e0b74 Mon Sep 17 00:00:00 2001 From: Yong He Date: Fri, 28 Jun 2019 22:20:57 +0800 Subject: [PATCH] Fix deadloop in proc subtask list Readdir of /proc/x/task/ will get direntry entries from tasks of specified taskgroup. Now the tasks slice is unsorted, use sort.SearchInts search entry from the slice may cause infinity loops. The fix is sort the slice before search. This issue could be easily reproduced via following steps, revise Readdir in pkg/sentry/fs/proc/task.go, force set taskInts into test slice []int{1, 11, 7, 5, 10, 6, 8, 3, 9, 2, 4}, then run docker image and run ls /proc/1/task, the command will cause infinity loops. --- pkg/sentry/fs/proc/task.go | 1 + 1 file changed, 1 insertion(+) diff --git a/pkg/sentry/fs/proc/task.go b/pkg/sentry/fs/proc/task.go index b2e36aeee..fc4c9ea4f 100644 --- a/pkg/sentry/fs/proc/task.go +++ b/pkg/sentry/fs/proc/task.go @@ -184,6 +184,7 @@ func (f *subtasksFile) Readdir(ctx context.Context, file *fs.File, ser fs.Dentry taskInts = append(taskInts, int(tid)) } + sort.Sort(sort.IntSlice(taskInts)) // Find the task to start at. idx := sort.SearchInts(taskInts, int(offset)) if idx == len(taskInts) {