From ffac9ff3579ca36fc8edf12cb49b0dcae55d5156 Mon Sep 17 00:00:00 2001
From: Richard Li <tianqi.li@oracle.com>
Date: Thu, 17 Oct 2024 23:56:11 +0000
Subject: [PATCH] lockup: Print tasks which have been on-cpu for too long

Orabug: 37187006
Signed-off-by: Richard Li <tianqi.li@oracle.com>
---
 drgn_tools/lockup.py | 70 ++++++++++++++++++++++++++++++++++++++++++++
 tests/test_lockup.py |  7 +++++
 2 files changed, 77 insertions(+)
 create mode 100644 drgn_tools/lockup.py
 create mode 100644 tests/test_lockup.py

diff --git a/drgn_tools/lockup.py b/drgn_tools/lockup.py
new file mode 100644
index 00000000..8c1039f6
--- /dev/null
+++ b/drgn_tools/lockup.py
@@ -0,0 +1,70 @@
+# Copyright (c) 2024, Oracle and/or its affiliates.
+# Licensed under the Universal Permissive License v 1.0 as shown at https://oss.oracle.com/licenses/upl/
+import argparse
+
+from drgn import Program
+from drgn.helpers.common import escape_ascii_string
+from drgn.helpers.linux.cpumask import for_each_online_cpu
+from drgn.helpers.linux.percpu import per_cpu
+
+from drgn_tools.bt import bt
+from drgn_tools.corelens import CorelensModule
+from drgn_tools.task import task_lastrun2now
+from drgn_tools.util import timestamp_str
+
+
+def scan_lockup(
+    prog: Program, min_run_time_seconds: int = 1, skip_swapper: bool = True
+) -> None:
+    """
+    Scan potential lockups on cpus.
+
+    :param prog: drgn program
+    :param min_run_time_seconds: int
+    :param skip_swapper: bool
+    """
+    nr_processes = 0
+    for cpus in for_each_online_cpu(prog):
+        runqueue = per_cpu(prog["runqueues"], cpus)
+        curr_task_addr = runqueue.curr.value_()
+        curr_task = runqueue.curr[0]
+        comm = escape_ascii_string(curr_task.comm.string_())
+        pid = curr_task.pid.value_()
+        run_time = task_lastrun2now(curr_task)
+        prio = curr_task.prio.value_()
+        if run_time < min_run_time_seconds * 1e9:
+            continue
+        if skip_swapper and comm == f"swapper/{cpus}":
+            continue
+        print(f"CPU {cpus} RUNQUEUE: {runqueue.address_of_().value_():x}")
+        print(
+            f"  PID: {pid:<6d}  TASK: {curr_task_addr:x}  PRIO: {prio}"
+            f'  COMMAND: "{comm}"',
+            f"  LOCKUP TIME: {timestamp_str(run_time)}",
+        )
+        print("\nCalltrace:")
+        bt(task_or_prog=curr_task.address_of_())
+        print()
+        nr_processes += 1
+
+    print(
+        f"We found {nr_processes} processes running more than {min_run_time_seconds} seconds."
+    )
+
+
+class LockUp(CorelensModule):
+    """Print tasks which have been on-cpu for too long"""
+
+    name = "lockup"
+
+    def add_args(self, parser: argparse.ArgumentParser) -> None:
+        parser.add_argument(
+            "--time",
+            "-t",
+            type=float,
+            default=2,
+            help="list all the processes that have been running more than <time> seconds",
+        )
+
+    def run(self, prog: Program, args: argparse.Namespace) -> None:
+        scan_lockup(prog, args.time)
diff --git a/tests/test_lockup.py b/tests/test_lockup.py
new file mode 100644
index 00000000..03ab3fab
--- /dev/null
+++ b/tests/test_lockup.py
@@ -0,0 +1,7 @@
+# Copyright (c) 2024, Oracle and/or its affiliates.
+# Licensed under the Universal Permissive License v 1.0 as shown at https://oss.oracle.com/licenses/upl/
+from drgn_tools import lockup
+
+
+def test_lockup(prog):
+    lockup.scan_lockup(prog)