On Wed, 15 Sep 2021 14:37:10 +0200 <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > > cpus_read_unlock(); > > - return 0; > + return retval; > } > The issue was that the latest kernel uses cpu_read_unlock() instead of put_online_cpus(), other than that, it was trivial to fix. Below should apply cleanly to 5.14. -- Steve >From 4b6b08f2e45edda4c067ac40833e3c1f84383c0b Mon Sep 17 00:00:00 2001 From: "Qiang.Zhang" <qiang.zhang@xxxxxxxxxxxxx> 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@xxxxxxxxxxxxx Cc: <stable@xxxxxxxxxxxxxxx> Fixes: c8895e271f79 ("trace/osnoise: Support hotplug operations") Acked-by: Daniel Bristot de Oliveira <bristot@xxxxxxxxxx> Signed-off-by: Qiang.Zhang <qiang.zhang@xxxxxxxxxxxxx> Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx> Index: linux-test.git/kernel/trace/trace_osnoise.c =================================================================== --- linux-test.git.orig/kernel/trace/trace_osnoise.c +++ linux-test.git/kernel/trace/trace_osnoise.c @@ -1548,7 +1548,7 @@ static int start_kthread(unsigned int cp static int start_per_cpu_kthreads(struct trace_array *tr) { struct cpumask *current_mask = &save_cpumask; - int retval; + int retval = 0; int cpu; get_online_cpus(); @@ -1568,13 +1568,13 @@ static int start_per_cpu_kthreads(struct retval = start_kthread(cpu); if (retval) { stop_per_cpu_kthreads(); - return retval; + break; } } put_online_cpus(); - return 0; + return retval; } #ifdef CONFIG_HOTPLUG_CPU
