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| author | Wei Li <liwei391@huawei.com> | 2024-09-24 17:45:14 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-10-10 11:57:59 +0200 |
| commit | 79250decc9ab0d9ba96dc73106978384c75d5ae0 (patch) | |
| tree | 03a824cc16687bbec01a0780a8a3f649fc5b7642 /kernel | |
| parent | b8c118c2a2ad178b73a22d347067588806c45e6f (diff) | |
| download | linux-79250decc9ab0d9ba96dc73106978384c75d5ae0.tar.gz linux-79250decc9ab0d9ba96dc73106978384c75d5ae0.tar.bz2 linux-79250decc9ab0d9ba96dc73106978384c75d5ae0.zip | |
tracing/hwlat: Fix a race during cpuhp processing
commit 2a13ca2e8abb12ee43ada8a107dadca83f140937 upstream.
The cpuhp online/offline processing race also exists in percpu-mode hwlat
tracer in theory, apply the fix too. That is:
T1 | T2
[CPUHP_ONLINE] | cpu_device_down()
hwlat_hotplug_workfn() |
| cpus_write_lock()
| takedown_cpu(1)
| cpus_write_unlock()
[CPUHP_OFFLINE] |
cpus_read_lock() |
start_kthread(1) |
cpus_read_unlock() |
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20240924094515.3561410-5-liwei391@huawei.com
Fixes: ba998f7d9531 ("trace/hwlat: 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>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/trace/trace_hwlat.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/kernel/trace/trace_hwlat.c b/kernel/trace/trace_hwlat.c index b791524a6536..3bd6071441ad 100644 --- a/kernel/trace/trace_hwlat.c +++ b/kernel/trace/trace_hwlat.c @@ -520,6 +520,8 @@ static void hwlat_hotplug_workfn(struct work_struct *dummy) if (!hwlat_busy || hwlat_data.thread_mode != MODE_PER_CPU) goto out_unlock; + if (!cpu_online(cpu)) + goto out_unlock; if (!cpumask_test_cpu(cpu, tr->tracing_cpumask)) goto out_unlock; |