]> git.ipfire.org Git - thirdparty/kernel/stable.git/commit
tracing: Fix potential deadlock in cpu hotplug with osnoise
authorLuo Haiyang <luo.haiyang@zte.com.cn>
Mon, 30 Mar 2026 18:37:39 +0000 (14:37 -0400)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Sat, 11 Apr 2026 12:16:35 +0000 (14:16 +0200)
commit7aa095ce7d224308cb6979956f0de8607df93d4f
tree3e854992c972c8526b85fa3b0363631f56980450
parent4cca3eff2099b18672934a39cee70aed835d652c
tracing: Fix potential deadlock in cpu hotplug with osnoise

[ Upstream commit 1f9885732248d22f788e4992c739a98c88ab8a55 ]

The following sequence may leads deadlock in cpu hotplug:

    task1        task2        task3
    -----        -----        -----

 mutex_lock(&interface_lock)

            [CPU GOING OFFLINE]

            cpus_write_lock();
            osnoise_cpu_die();
              kthread_stop(task3);
                wait_for_completion();

                      osnoise_sleep();
                        mutex_lock(&interface_lock);

 cpus_read_lock();

 [DEAD LOCK]

Fix by swap the order of cpus_read_lock() and mutex_lock(&interface_lock).

Cc: stable@vger.kernel.org
Cc: <mathieu.desnoyers@efficios.com>
Cc: <zhang.run@zte.com.cn>
Cc: <yang.tao172@zte.com.cn>
Cc: <ran.xiaokai@zte.com.cn>
Fixes: bce29ac9ce0bb ("trace: Add osnoise tracer")
Link: https://patch.msgid.link/20260326141953414bVSj33dAYktqp9Oiyizq8@zte.com.cn
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Luo Haiyang <luo.haiyang@zte.com.cn>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
[ adapted guard() macros to lock/unlock calls ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
kernel/trace/trace_osnoise.c