Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Alexei Starovoitov says:

====================
pull-request: bpf-next 2020-09-23

The following pull-request contains BPF updates for your *net-next* tree.

We've added 95 non-merge commits during the last 22 day(s) which contain
a total of 124 files changed, 4211 insertions(+), 2040 deletions(-).

The main changes are:

1) Full multi function support in libbpf, from Andrii.

2) Refactoring of function argument checks, from Lorenz.

3) Make bpf_tail_call compatible with functions (subprograms), from Maciej.

4) Program metadata support, from YiFei.

5) bpf iterator optimizations, from Yonghong.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 11 insertions, 4 deletions

diff --git a/kernel/bpf/task_iter.c b/kernel/bpf/task_iter.c
index 99af4cea1102..5b6af30bfbcd 100644
--- a/kernel/bpf/task_iter.c
+++ b/kernel/bpf/task_iter.c
@@ -22,7 +22,8 @@ struct bpf_iter_seq_task_info {
 };
 
 static struct task_struct *task_seq_get_next(struct pid_namespace *ns,
-					     u32 *tid)
+					     u32 *tid,
+					     bool skip_if_dup_files)
 {
 	struct task_struct *task = NULL;
 	struct pid *pid;
@@ -36,6 +37,12 @@ retry:
 		if (!task) {
 			++*tid;
 			goto retry;
+		} else if (skip_if_dup_files && task->tgid != task->pid &&
+			   task->files == task->group_leader->files) {
+			put_task_struct(task);
+			task = NULL;
+			++*tid;
+			goto retry;
 		}
 	}
 	rcu_read_unlock();
@@ -48,7 +55,7 @@ static void *task_seq_start(struct seq_file *seq, loff_t *pos)
 	struct bpf_iter_seq_task_info *info = seq->private;
 	struct task_struct *task;
 
-	task = task_seq_get_next(info->common.ns, &info->tid);
+	task = task_seq_get_next(info->common.ns, &info->tid, false);
 	if (!task)
 		return NULL;
 
@@ -65,7 +72,7 @@ static void *task_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 	++*pos;
 	++info->tid;
 	put_task_struct((struct task_struct *)v);
-	task = task_seq_get_next(info->common.ns, &info->tid);
+	task = task_seq_get_next(info->common.ns, &info->tid, false);
 	if (!task)
 		return NULL;
 
@@ -148,7 +155,7 @@ again:
 		curr_files = *fstruct;
 		curr_fd = info->fd;
 	} else {
-		curr_task = task_seq_get_next(ns, &curr_tid);
+		curr_task = task_seq_get_next(ns, &curr_tid, true);
 		if (!curr_task)
 			return NULL;