This is a note to let you know that I've just added the patch titled
tracing: Add tracing_reset_all_online_cpus_unlocked() function
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
tracing-add-tracing_reset_all_online_cpus_unlocked-function.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From e18eb8783ec4949adebc7d7b0fdb65f65bfeefd9 Mon Sep 17 00:00:00 2001
From: "Steven Rostedt (Google)" <rostedt@xxxxxxxxxxx>
Date: Wed, 23 Nov 2022 14:25:57 -0500
Subject: tracing: Add tracing_reset_all_online_cpus_unlocked() function
From: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
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@xxxxxxxxxxx
Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Zheng Yejian <zhengyejian1@xxxxxxxxxx>
Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
Signed-off-by: Zheng Yejian <zhengyejian1@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/trace/trace.c | 11 ++++++++++-
kernel/trace/trace.h | 1 +
kernel/trace/trace_events.c | 2 +-
kernel/trace/trace_events_synth.c | 2 --
4 files changed, 12 insertions(+), 4 deletions(-)
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2175,10 +2175,12 @@ void tracing_reset_online_cpus(struct ar
}
/* 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.
--- 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);
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -2974,7 +2974,7 @@ static void trace_module_remove_events(s
* 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,
--- 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
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
* occur.
*/
tracing_reset_all_online_cpus();
- mutex_unlock(&trace_types_lock);
}
return ret;
Patches currently in stable-queue which might be from rostedt@xxxxxxxxxxx are
queue-5.15/tracing-add-tracing_reset_all_online_cpus_unlocked-function.patch
