[PATCH AUTOSEL 5.4 5/7] selftests/ftrace: Correctly enable event in instance-event.tc

[PATCH AUTOSEL 5.4 5/7] selftests/ftrace: Correctly enable event in instance-event.tc

[Sasha Levin]

From: Zheng Yejian <zhengyejian1@huawei.com>

[ Upstream commit f4e4ada586995b17f828c6d147d1800eb1471450 ]

Function instance_set() expects to enable event 'sched_switch', so we
should set 1 to its 'enable' file.

Testcase passed after this patch:
  # ./ftracetest test.d/instances/instance-event.tc
  === Ftrace unit tests ===
  [1] Test creation and deletion of trace instances while setting an event
  [PASS]

  # of passed:  1
  # of failed:  0
  # of unresolved:  0
  # of untested:  0
  # of unsupported:  0
  # of xfailed:  0
  # of undefined(test bug):  0

Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 .../testing/selftests/ftrace/test.d/instances/instance-event.tc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/ftrace/test.d/instances/instance-event.tc b/tools/testing/selftests/ftrace/test.d/instances/instance-event.tc
index 4fa0f79144f4a..9473934a573a1 100644
--- a/tools/testing/selftests/ftrace/test.d/instances/instance-event.tc
+++ b/tools/testing/selftests/ftrace/test.d/instances/instance-event.tc
@@ -43,7 +43,7 @@ instance_read() {
 
 instance_set() {
         while :; do
-                echo 1 > foo/events/sched/sched_switch
+                echo 1 > foo/events/sched/sched_switch/enable
         done 2> /dev/null
 }
 
-- 
2.40.1

[PATCH AUTOSEL 5.4 6/7] ring-buffer: Avoid softlockup in ring_buffer_resize()

[Sasha Levin]

From: Zheng Yejian <zhengyejian1@huawei.com>

[ Upstream commit f6bd2c92488c30ef53b5bd80c52f0a7eee9d545a ]

When user resize all trace ring buffer through file 'buffer_size_kb',
then in ring_buffer_resize(), kernel allocates buffer pages for each
cpu in a loop.

If the kernel preemption model is PREEMPT_NONE and there are many cpus
and there are many buffer pages to be allocated, it may not give up cpu
for a long time and finally cause a softlockup.

To avoid it, call cond_resched() after each cpu buffer allocation.

Link: https://lore.kernel.org/linux-trace-kernel/20230906081930.3939106-1-zhengyejian1@huawei.com

Cc: <mhiramat@kernel.org>
Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 kernel/trace/ring_buffer.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 445475c229b3a..2a4fb4f1e3cad 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -1821,6 +1821,8 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size,
 				err = -ENOMEM;
 				goto out_err;
 			}
+
+			cond_resched();
 		}
 
 		get_online_cpus();
-- 
2.40.1