The patch below does not apply to the 5.14-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 4b6b08f2e45edda4c067ac40833e3c1f84383c0b Mon Sep 17 00:00:00 2001

From: "Qiang.Zhang" qiang.zhang@windriver.com Date: Tue, 31 Aug 2021 10:29:19 +0800 Subject: [PATCH] tracing/osnoise: Fix missed cpus_read_unlock() in start_per_cpu_kthreads()

When start_kthread() return error, the cpus_read_unlock() need to be called.

Link: https://lkml.kernel.org/r/20210831022919.27630-1-qiang.zhang@windriver.com

Cc: stable@vger.kernel.org Fixes: c8895e271f79 ("trace/osnoise: Support hotplug operations") Acked-by: Daniel Bristot de Oliveira bristot@kernel.org Signed-off-by: Qiang.Zhang qiang.zhang@windriver.com Signed-off-by: Steven Rostedt (VMware) rostedt@goodmis.org

diff --git a/kernel/trace/trace_osnoise.c b/kernel/trace/trace_osnoise.c index 65b08b8e5bf8..ce053619f289 100644 --- a/kernel/trace/trace_osnoise.c +++ b/kernel/trace/trace_osnoise.c @@ -1548,7 +1548,7 @@ static int start_kthread(unsigned int cpu) static int start_per_cpu_kthreads(struct trace_array *tr) { struct cpumask *current_mask = &save_cpumask; - int retval; + int retval = 0; int cpu;

cpus_read_lock(); @@ -1568,13 +1568,13 @@ static int start_per_cpu_kthreads(struct trace_array *tr) retval = start_kthread(cpu); if (retval) { stop_per_cpu_kthreads(); - return retval; + break; } }

cpus_read_unlock();

- return 0; + return retval; }

#ifdef CONFIG_HOTPLUG_CPU