1 files changed, 63 insertions, 0 deletions

diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_task.c b/tools/testing/selftests/bpf/progs/bpf_iter_task.c
index c86b93f33b32..96131b9a1caa 100644
--- a/tools/testing/selftests/bpf/progs/bpf_iter_task.c
+++ b/tools/testing/selftests/bpf/progs/bpf_iter_task.c
@@ -2,9 +2,14 @@
 /* Copyright (c) 2020 Facebook */
 #include "bpf_iter.h"
 #include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
 
 char _license[] SEC("license") = "GPL";
 
+uint32_t tid = 0;
+int num_unknown_tid = 0;
+int num_known_tid = 0;
+
 SEC("iter/task")
 int dump_task(struct bpf_iter__task *ctx)
 {
@@ -17,9 +22,67 @@ int dump_task(struct bpf_iter__task *ctx)
 		return 0;
 	}
 
+	if (task->pid != tid)
+		num_unknown_tid++;
+	else
+		num_known_tid++;
+
 	if (ctx->meta->seq_num == 0)
 		BPF_SEQ_PRINTF(seq, "    tgid      gid\n");
 
 	BPF_SEQ_PRINTF(seq, "%8d %8d\n", task->tgid, task->pid);
 	return 0;
 }
+
+int num_expected_failure_copy_from_user_task = 0;
+int num_success_copy_from_user_task = 0;
+
+SEC("iter.s/task")
+int dump_task_sleepable(struct bpf_iter__task *ctx)
+{
+	struct seq_file *seq = ctx->meta->seq;
+	struct task_struct *task = ctx->task;
+	static const char info[] = "    === END ===";
+	struct pt_regs *regs;
+	void *ptr;
+	uint32_t user_data = 0;
+	int ret;
+
+	if (task == (void *)0) {
+		BPF_SEQ_PRINTF(seq, "%s\n", info);
+		return 0;
+	}
+
+	/* Read an invalid pointer and ensure we get an error */
+	ptr = NULL;
+	ret = bpf_copy_from_user_task(&user_data, sizeof(uint32_t), ptr, task, 0);
+	if (ret) {
+		++num_expected_failure_copy_from_user_task;
+	} else {
+		BPF_SEQ_PRINTF(seq, "%s\n", info);
+		return 0;
+	}
+
+	/* Try to read the contents of the task's instruction pointer from the
+	 * remote task's address space.
+	 */
+	regs = (struct pt_regs *)bpf_task_pt_regs(task);
+	if (regs == (void *)0) {
+		BPF_SEQ_PRINTF(seq, "%s\n", info);
+		return 0;
+	}
+	ptr = (void *)PT_REGS_IP(regs);
+
+	ret = bpf_copy_from_user_task(&user_data, sizeof(uint32_t), ptr, task, 0);
+	if (ret) {
+		BPF_SEQ_PRINTF(seq, "%s\n", info);
+		return 0;
+	}
+	++num_success_copy_from_user_task;
+
+	if (ctx->meta->seq_num == 0)
+		BPF_SEQ_PRINTF(seq, "    tgid      gid     data\n");
+
+	BPF_SEQ_PRINTF(seq, "%8d %8d %8d\n", task->tgid, task->pid, user_data);
+	return 0;
+}