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* [PATCH 2/4] refcount: add ref_trace_final_put tracepoint
       [not found] <20260704-refcount-final-put-trace-v1-0-b48746da1f27@mavick.dev>
@ 2026-07-04 11:34 ` Eugene Mavick
  2026-07-04 11:34 ` [PATCH 3/4] percpu-refcount: add ref_trace_final_put trace Eugene Mavick
  1 sibling, 0 replies; 6+ messages in thread
From: Eugene Mavick @ 2026-07-04 11:34 UTC (permalink / raw)
  To: Will Deacon, Peter Zijlstra, Boqun Feng, Mark Rutland, Gary Guo,
	Steven Rostedt, Masami Hiramatsu, Mathieu Desnoyers,
	Andrew Morton, Dennis Zhou, Tejun Heo, Christoph Lameter
  Cc: linux-kernel, linux-trace-kernel, linux-mm, Eugene Mavick

Add the ref_trace_final_put tracepoint to __refcount_sub_and_test().
This fires when a refcount_t reaches zero, capturing the caller
address, the function name, and the refcount_t address.

Signed-off-by: Eugene Mavick <m@mavick.dev>
---
 include/linux/refcount.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/include/linux/refcount.h b/include/linux/refcount.h
index ba7657ced281..7b1fbf326a21 100644
--- a/include/linux/refcount.h
+++ b/include/linux/refcount.h
@@ -107,6 +107,7 @@
 #include <linux/limits.h>
 #include <linux/refcount_types.h>
 #include <linux/spinlock_types.h>
+#include <linux/ref_trace.h>
 
 struct mutex;
 
@@ -393,6 +394,7 @@ bool __refcount_sub_and_test(int i, refcount_t *r, int *oldp)
 
 	if (old > 0 && old == i) {
 		smp_acquire__after_ctrl_dep();
+		trace_ref_final_put(r);
 		return true;
 	}
 

-- 
2.51.2


^ permalink raw reply related	[flat|nested] 6+ messages in thread
* [PATCH 3/4] percpu-refcount: add ref_trace_final_put trace
       [not found] <20260704-refcount-final-put-trace-v1-0-b48746da1f27@mavick.dev>
  2026-07-04 11:34 ` [PATCH 2/4] refcount: add ref_trace_final_put tracepoint Eugene Mavick
@ 2026-07-04 11:34 ` Eugene Mavick
  1 sibling, 0 replies; 6+ messages in thread
From: Eugene Mavick @ 2026-07-04 11:34 UTC (permalink / raw)
  To: Will Deacon, Peter Zijlstra, Boqun Feng, Mark Rutland, Gary Guo,
	Steven Rostedt, Masami Hiramatsu, Mathieu Desnoyers,
	Andrew Morton, Dennis Zhou, Tejun Heo, Christoph Lameter
  Cc: linux-kernel, linux-trace-kernel, linux-mm, Eugene Mavick

Add the ref_trace_final_put tracepoint to percpu_ref_put_many().
The tracepoint fires when the atomic counter reaches zero in the
atomic fallback path (after percpu_ref_kill() has been called).

Signed-off-by: Eugene Mavick <m@mavick.dev>
---
 include/linux/percpu-refcount.h | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/include/linux/percpu-refcount.h b/include/linux/percpu-refcount.h
index d73a1c08c3e3..55543ecdf60c 100644
--- a/include/linux/percpu-refcount.h
+++ b/include/linux/percpu-refcount.h
@@ -55,6 +55,7 @@
 #include <linux/rcupdate.h>
 #include <linux/types.h>
 #include <linux/gfp.h>
+#include <linux/ref_trace.h>
 
 struct percpu_ref;
 typedef void (percpu_ref_func_t)(struct percpu_ref *);
@@ -331,8 +332,10 @@ static inline void percpu_ref_put_many(struct percpu_ref *ref, unsigned long nr)
 
 	if (__ref_is_percpu(ref, &percpu_count))
 		this_cpu_sub(*percpu_count, nr);
-	else if (unlikely(atomic_long_sub_and_test(nr, &ref->data->count)))
+	else if (unlikely(atomic_long_sub_and_test(nr, &ref->data->count))) {
+		trace_ref_final_put(ref);
 		ref->data->release(ref);
+	}
 
 	rcu_read_unlock();
 }

-- 
2.51.2


^ permalink raw reply related	[flat|nested] 6+ messages in thread
* [PATCH 2/4] refcount: add ref_trace_final_put tracepoint
  2026-07-04 23:19 [PATCH 0/4] tracing: add ref_trace_final_put tracing Eugene Mavick
@ 2026-07-04 23:19 ` Eugene Mavick
  0 siblings, 0 replies; 6+ messages in thread
From: Eugene Mavick @ 2026-07-04 23:19 UTC (permalink / raw)
  To: Will Deacon, Peter Zijlstra, Boqun Feng, Mark Rutland, Gary Guo,
	Steven Rostedt, Masami Hiramatsu, Mathieu Desnoyers,
	Andrew Morton, Dennis Zhou, Tejun Heo, Christoph Lameter
  Cc: linux-kernel, linux-trace-kernel, linux-mm, Eugene Mavick

Add the ref_trace_final_put tracepoint to __refcount_sub_and_test().
This fires when a refcount_t reaches zero, capturing the caller
address, the function name, and the refcount_t address.

Signed-off-by: Eugene Mavick <m@mavick.dev>
---
 include/linux/refcount.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/include/linux/refcount.h b/include/linux/refcount.h
index ba7657ced281..7b1fbf326a21 100644
--- a/include/linux/refcount.h
+++ b/include/linux/refcount.h
@@ -107,6 +107,7 @@
 #include <linux/limits.h>
 #include <linux/refcount_types.h>
 #include <linux/spinlock_types.h>
+#include <linux/ref_trace.h>
 
 struct mutex;
 
@@ -393,6 +394,7 @@ bool __refcount_sub_and_test(int i, refcount_t *r, int *oldp)
 
 	if (old > 0 && old == i) {
 		smp_acquire__after_ctrl_dep();
+		trace_ref_final_put(r);
 		return true;
 	}
 

-- 
2.51.2


^ permalink raw reply related	[flat|nested] 6+ messages in thread
* [PATCH 2/4] refcount: add ref_trace_final_put tracepoint
  2026-07-05  0:36 [PATCH 0/4] tracing: add ref_trace_final_put tracing Eugene Mavick
@ 2026-07-05  0:36 ` Eugene Mavick
  0 siblings, 0 replies; 6+ messages in thread
From: Eugene Mavick @ 2026-07-05  0:36 UTC (permalink / raw)
  To: Will Deacon, Peter Zijlstra, Boqun Feng, Mark Rutland, Gary Guo,
	Steven Rostedt, Masami Hiramatsu, Mathieu Desnoyers,
	Andrew Morton, Dennis Zhou, Tejun Heo, Christoph Lameter
  Cc: linux-kernel, linux-trace-kernel, linux-mm, Eugene Mavick

Add the ref_trace_final_put tracepoint to __refcount_sub_and_test().
This fires when a refcount_t reaches zero, capturing the caller
address, the function name, and the refcount_t address.

Signed-off-by: Eugene Mavick <m@mavick.dev>
---
 include/linux/refcount.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/include/linux/refcount.h b/include/linux/refcount.h
index ba7657ced281..7b1fbf326a21 100644
--- a/include/linux/refcount.h
+++ b/include/linux/refcount.h
@@ -107,6 +107,7 @@
 #include <linux/limits.h>
 #include <linux/refcount_types.h>
 #include <linux/spinlock_types.h>
+#include <linux/ref_trace.h>
 
 struct mutex;
 
@@ -393,6 +394,7 @@ bool __refcount_sub_and_test(int i, refcount_t *r, int *oldp)
 
 	if (old > 0 && old == i) {
 		smp_acquire__after_ctrl_dep();
+		trace_ref_final_put(r);
 		return true;
 	}
 

-- 
2.51.2


^ permalink raw reply related	[flat|nested] 6+ messages in thread
* [PATCH 2/4] refcount: add ref_trace_final_put tracepoint
  2026-07-05  1:20 [PATCH 0/4] tracing: add ref_trace_final_put tracing Eugene Mavick via B4 Relay
@ 2026-07-05  1:20 ` Eugene Mavick via B4 Relay
  2026-07-06 10:07   ` Usama Arif
  0 siblings, 1 reply; 6+ messages in thread
From: Eugene Mavick via B4 Relay @ 2026-07-05  1:20 UTC (permalink / raw)
  To: Will Deacon, Peter Zijlstra, Boqun Feng, Mark Rutland, Gary Guo,
	Steven Rostedt, Masami Hiramatsu, Mathieu Desnoyers,
	Andrew Morton, Dennis Zhou, Tejun Heo, Christoph Lameter
  Cc: linux-kernel, linux-trace-kernel, linux-mm, Eugene Mavick

From: Eugene Mavick <m@mavick.dev>

Add the ref_trace_final_put tracepoint to __refcount_sub_and_test().
This fires when a refcount_t reaches zero, capturing the caller
address, the function name, and the refcount_t address.

Signed-off-by: Eugene Mavick <m@mavick.dev>
---
 include/linux/refcount.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/include/linux/refcount.h b/include/linux/refcount.h
index ba7657ced281..7b1fbf326a21 100644
--- a/include/linux/refcount.h
+++ b/include/linux/refcount.h
@@ -107,6 +107,7 @@
 #include <linux/limits.h>
 #include <linux/refcount_types.h>
 #include <linux/spinlock_types.h>
+#include <linux/ref_trace.h>
 
 struct mutex;
 
@@ -393,6 +394,7 @@ bool __refcount_sub_and_test(int i, refcount_t *r, int *oldp)
 
 	if (old > 0 && old == i) {
 		smp_acquire__after_ctrl_dep();
+		trace_ref_final_put(r);
 		return true;
 	}
 

-- 
2.51.2



^ permalink raw reply related	[flat|nested] 6+ messages in thread
* Re: [PATCH 2/4] refcount: add ref_trace_final_put tracepoint
  2026-07-05  1:20 ` [PATCH 2/4] refcount: add ref_trace_final_put tracepoint Eugene Mavick via B4 Relay
@ 2026-07-06 10:07   ` Usama Arif
  0 siblings, 0 replies; 6+ messages in thread
From: Usama Arif @ 2026-07-06 10:07 UTC (permalink / raw)
  To: Eugene Mavick via B4 Relay
  Cc: Usama Arif, Will Deacon, Peter Zijlstra, Boqun Feng, Mark Rutland,
	Gary Guo, Steven Rostedt, Masami Hiramatsu, Mathieu Desnoyers,
	Andrew Morton, Dennis Zhou, Tejun Heo, Christoph Lameter,
	linux-kernel, linux-trace-kernel, linux-mm, Eugene Mavick

On Sun, 05 Jul 2026 09:20:52 +0800 Eugene Mavick via B4 Relay <devnull+m.mavick.dev@kernel.org> wrote:

> From: Eugene Mavick <m@mavick.dev>
> 
> Add the ref_trace_final_put tracepoint to __refcount_sub_and_test().
> This fires when a refcount_t reaches zero, capturing the caller
> address, the function name, and the refcount_t address.
> 
> Signed-off-by: Eugene Mavick <m@mavick.dev>
> ---
>  include/linux/refcount.h | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/include/linux/refcount.h b/include/linux/refcount.h
> index ba7657ced281..7b1fbf326a21 100644
> --- a/include/linux/refcount.h
> +++ b/include/linux/refcount.h
> @@ -107,6 +107,7 @@
>  #include <linux/limits.h>
>  #include <linux/refcount_types.h>
>  #include <linux/spinlock_types.h>
> +#include <linux/ref_trace.h>
>  
>  struct mutex;
>  
> @@ -393,6 +394,7 @@ bool __refcount_sub_and_test(int i, refcount_t *r, int *oldp)
>  
>  	if (old > 0 && old == i) {
>  		smp_acquire__after_ctrl_dep();
> +		trace_ref_final_put(r);

Should refcount_dec_if_one() also fire the tracepoint?

>  		return true;
>  	}
>  
> 
> -- 
> 2.51.2
> 
> 
> 

^ permalink raw reply	[flat|nested] 6+ messages in thread
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     [not found] <20260704-refcount-final-put-trace-v1-0-b48746da1f27@mavick.dev>
2026-07-04 11:34 ` [PATCH 2/4] refcount: add ref_trace_final_put tracepoint Eugene Mavick
2026-07-04 11:34 ` [PATCH 3/4] percpu-refcount: add ref_trace_final_put trace Eugene Mavick
2026-07-04 23:19 [PATCH 0/4] tracing: add ref_trace_final_put tracing Eugene Mavick
2026-07-04 23:19 ` [PATCH 2/4] refcount: add ref_trace_final_put tracepoint Eugene Mavick
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2026-07-05  0:36 [PATCH 0/4] tracing: add ref_trace_final_put tracing Eugene Mavick
2026-07-05  0:36 ` [PATCH 2/4] refcount: add ref_trace_final_put tracepoint Eugene Mavick
2026-07-05  1:20 [PATCH 0/4] tracing: add ref_trace_final_put tracing Eugene Mavick via B4 Relay
2026-07-05  1:20 ` [PATCH 2/4] refcount: add ref_trace_final_put tracepoint Eugene Mavick via B4 Relay
2026-07-06 10:07   ` Usama Arif

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