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| author | Wei Li <liwei391@huawei.com> | 2024-09-24 17:45:11 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-10-10 12:01:06 +0200 |
| commit | 3670051acbca6537641c6033ae31e51110812ad8 (patch) | |
| tree | 48b87d68b2b2ddd938a7be417ddb467b8919e807 | |
| parent | a0d9c0cd5856191e095cf43a2e141b73945b7716 (diff) | |
| download | linux-stable-3670051acbca6537641c6033ae31e51110812ad8.tar.gz linux-stable-3670051acbca6537641c6033ae31e51110812ad8.tar.bz2 linux-stable-3670051acbca6537641c6033ae31e51110812ad8.zip | |
tracing/timerlat: Fix duplicated kthread creation due to CPU online/offline
commit 0bb0a5c12ecf36ad561542bbb95f96355e036a02 upstream.
osnoise_hotplug_workfn() is the asynchronous online callback for
"trace/osnoise:online". It may be congested when a CPU goes online and
offline repeatedly and is invoked for multiple times after a certain
online.
This will lead to kthread leak and timer corruption. Add a check
in start_kthread() to prevent this situation.
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20240924094515.3561410-2-liwei391@huawei.com
Fixes: c8895e271f79 ("trace/osnoise: Support hotplug operations")
Signed-off-by: Wei Li <liwei391@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | kernel/trace/trace_osnoise.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/kernel/trace/trace_osnoise.c b/kernel/trace/trace_osnoise.c index 26bb7fa51416..3e2bc029fa8c 100644 --- a/kernel/trace/trace_osnoise.c +++ b/kernel/trace/trace_osnoise.c @@ -2006,6 +2006,10 @@ static int start_kthread(unsigned int cpu) void *main = osnoise_main; char comm[24]; + /* Do not start a new thread if it is already running */ + if (per_cpu(per_cpu_osnoise_var, cpu).kthread) + return 0; + if (timerlat_enabled()) { snprintf(comm, 24, "timerlat/%d", cpu); main = timerlat_main; @@ -2060,11 +2064,10 @@ static int start_per_cpu_kthreads(void) if (cpumask_test_and_clear_cpu(cpu, &kthread_cpumask)) { struct task_struct *kthread; - kthread = per_cpu(per_cpu_osnoise_var, cpu).kthread; + kthread = xchg_relaxed(&(per_cpu(per_cpu_osnoise_var, cpu).kthread), NULL); if (!WARN_ON(!kthread)) kthread_stop(kthread); } - per_cpu(per_cpu_osnoise_var, cpu).kthread = NULL; } for_each_cpu(cpu, current_mask) { |