| Message ID | 20230620013052.1127047-1-zhengyejian1@huawei.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [5.15] tracing: Add tracing_reset_all_online_cpus_unlocked() function | expand |
On Tue, Jun 20, 2023 at 09:30:52AM +0800, Zheng Yejian wrote: > From: "Steven Rostedt (Google)" <rostedt@goodmis.org> > > commit e18eb8783ec4949adebc7d7b0fdb65f65bfeefd9 upstream. > > Currently the tracing_reset_all_online_cpus() requires the > trace_types_lock held. But only one caller of this function actually has > that lock held before calling it, and the other just takes the lock so > that it can call it. More users of this function is needed where the lock > is not held. > > Add a tracing_reset_all_online_cpus_unlocked() function for the one use > case that calls it without being held, and also add a lockdep_assert to > make sure it is held when called. > > Then have tracing_reset_all_online_cpus() take the lock internally, such > that callers do not need to worry about taking it. > > Link: https://lkml.kernel.org/r/20221123192741.658273220@goodmis.org > > Cc: Masami Hiramatsu <mhiramat@kernel.org> > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: Zheng Yejian <zhengyejian1@huawei.com> > Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> > > [Refers to commit message of 417d5ea6e735e5d88ffb6c436cf2938f3f476dd1, > this patch is pre-depended, and tracing_reset_all_online_cpus() should > be called after trace_types_lock is held as its comment describes.] > Fixes: 417d5ea6e735 ("tracing: Free buffers when a used dynamic event is removed") > Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com> All now queued up, thanks. greg k-h
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index f8b5abd6e36c..0202f23ae960 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -2175,10 +2175,12 @@ void tracing_reset_online_cpus(struct array_buffer *buf) } /* Must have trace_types_lock held */ -void tracing_reset_all_online_cpus(void) +void tracing_reset_all_online_cpus_unlocked(void) { struct trace_array *tr; + lockdep_assert_held(&trace_types_lock); + list_for_each_entry(tr, &ftrace_trace_arrays, list) { if (!tr->clear_trace) continue; @@ -2190,6 +2192,13 @@ void tracing_reset_all_online_cpus(void) } } +void tracing_reset_all_online_cpus(void) +{ + mutex_lock(&trace_types_lock); + tracing_reset_all_online_cpus_unlocked(); + mutex_unlock(&trace_types_lock); +} + /* * The tgid_map array maps from pid to tgid; i.e. the value stored at index i * is the tgid last observed corresponding to pid=i. diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 66b6c8395fbc..2c3d9b6ce148 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -580,6 +580,7 @@ int tracing_is_enabled(void); void tracing_reset_online_cpus(struct array_buffer *buf); void tracing_reset_current(int cpu); void tracing_reset_all_online_cpus(void); +void tracing_reset_all_online_cpus_unlocked(void); int tracing_open_generic(struct inode *inode, struct file *filp); int tracing_open_generic_tr(struct inode *inode, struct file *filp); bool tracing_is_disabled(void); diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 1aadc9a6487b..160298d285c0 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -2974,7 +2974,7 @@ static void trace_module_remove_events(struct module *mod) * over from this module may be passed to the new module events and * unexpected results may occur. */ - tracing_reset_all_online_cpus(); + tracing_reset_all_online_cpus_unlocked(); } static int trace_module_notify(struct notifier_block *self, diff --git a/kernel/trace/trace_events_synth.c b/kernel/trace/trace_events_synth.c index 2fdf3fd591e1..08c7df42ade7 100644 --- a/kernel/trace/trace_events_synth.c +++ b/kernel/trace/trace_events_synth.c @@ -1416,7 +1416,6 @@ int synth_event_delete(const char *event_name) mutex_unlock(&event_mutex); if (mod) { - mutex_lock(&trace_types_lock); /* * It is safest to reset the ring buffer if the module * being unloaded registered any events that were @@ -1428,7 +1427,6 @@ int synth_event_delete(const char *event_name) * occur. */ tracing_reset_all_online_cpus(); - mutex_unlock(&trace_types_lock); } return ret;