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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, kernel-team@android.com,
        Ingo Molnar <mingo@redhat.com>,
        Michael Sartain <mikesart@gmail.com>,
        Joel Fernandes <joelaf@google.com>,
        "Steven Rostedt (VMware)" <rostedt@goodmis.org>
Subject: [PATCH 4.4 062/190] tracing: Treat recording comm for idle task as a success
Date:   Thu, 20 May 2021 11:22:06 +0200
Message-Id: <20210520092104.215509374@linuxfoundation.org>
In-Reply-To: <20210520092102.149300807@linuxfoundation.org>
References: <20210520092102.149300807@linuxfoundation.org>
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From: Joel Fernandes <joelaf@google.com>

commit eaf260ac04d9b4cf9f458d5c97555bfff2da526e upstream.

Currently we stop recording comm for non-idle tasks when switching from/to idle
task since we treat that as a record failure. Fix that by treat recording of
comm for idle task as a success.

Link: http://lkml.kernel.org/r/20170706230023.17942-1-joelaf@google.com

Cc: kernel-team@android.com
Cc: Ingo Molnar <mingo@redhat.com>
Reported-by: Michael Sartain <mikesart@gmail.com>
Signed-off-by: Joel Fernandes <joelaf@google.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 kernel/trace/trace.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1564,7 +1564,11 @@ static int trace_save_cmdline(struct tas
 {
 	unsigned pid, idx;
 
-	if (!tsk->pid || unlikely(tsk->pid > PID_MAX_DEFAULT))
+	/* treat recording of idle task as a success */
+	if (!tsk->pid)
+		return 1;
+
+	if (unlikely(tsk->pid > PID_MAX_DEFAULT))
 		return 0;
 
 	/*