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| author | Nikita Yushchenko <nikita.yushchenko@virtuozzo.com> | 2022-01-09 18:34:59 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-01-27 13:05:18 +0300 |
| commit | cb77c81d347980f029e2e1ccdb80eb550d50eaf1 (patch) | |
| tree | fb73e152f602f0c41729b59e55824e8cd9c4ff28 /kernel/trace | |
| parent | 0d99b0a7c329b972d40f8f136576931673d4b261 (diff) | |
| download | linux-cb77c81d347980f029e2e1ccdb80eb550d50eaf1.tar.xz | |
tracing/osnoise: Properly unhook events if start_per_cpu_kthreads() fails
commit 0878355b51f5f26632e652c848a8e174bb02d22d upstream.
If start_per_cpu_kthreads() called from osnoise_workload_start() returns
error, event hooks are left in broken state: unhook_irq_events() called
but unhook_thread_events() and unhook_softirq_events() not called, and
trace_osnoise_callback_enabled flag not cleared.
On the next tracer enable, hooks get not installed due to
trace_osnoise_callback_enabled flag.
And on the further tracer disable an attempt to remove non-installed
hooks happened, hitting a WARN_ON_ONCE() in tracepoint_remove_func().
Fix the error path by adding the missing part of cleanup.
While at this, introduce osnoise_unhook_events() to avoid code
duplication between this error path and normal tracer disable.
Link: https://lkml.kernel.org/r/20220109153459.3701773-1-nikita.yushchenko@virtuozzo.com
Cc: stable@vger.kernel.org
Fixes: bce29ac9ce0b ("trace: Add osnoise tracer")
Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Nikita Yushchenko <nikita.yushchenko@virtuozzo.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel/trace')
| -rw-r--r-- | kernel/trace/trace_osnoise.c | 20 |
1 files changed, 16 insertions, 4 deletions
diff --git a/kernel/trace/trace_osnoise.c b/kernel/trace/trace_osnoise.c index c4f14fb98aaa..65a518649997 100644 --- a/kernel/trace/trace_osnoise.c +++ b/kernel/trace/trace_osnoise.c @@ -1932,6 +1932,13 @@ out_unhook_irq: return -EINVAL; } +static void osnoise_unhook_events(void) +{ + unhook_thread_events(); + unhook_softirq_events(); + unhook_irq_events(); +} + static int __osnoise_tracer_start(struct trace_array *tr) { int retval; @@ -1949,7 +1956,14 @@ static int __osnoise_tracer_start(struct trace_array *tr) retval = start_per_cpu_kthreads(tr); if (retval) { - unhook_irq_events(); + trace_osnoise_callback_enabled = false; + /* + * Make sure that ftrace_nmi_enter/exit() see + * trace_osnoise_callback_enabled as false before continuing. + */ + barrier(); + + osnoise_unhook_events(); return retval; } @@ -1981,9 +1995,7 @@ static void osnoise_tracer_stop(struct trace_array *tr) stop_per_cpu_kthreads(); - unhook_irq_events(); - unhook_softirq_events(); - unhook_thread_events(); + osnoise_unhook_events(); osnoise_busy = false; } |