From: Eugene Mavick via B4 Relay <devnull+m.mavick.dev@kernel.org>
To: Will Deacon <will@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Boqun Feng <boqun@kernel.org>,
Mark Rutland <mark.rutland@arm.com>, Gary Guo <gary@garyguo.net>,
Steven Rostedt <rostedt@goodmis.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Andrew Morton <akpm@linux-foundation.org>,
Dennis Zhou <dennis@kernel.org>, Tejun Heo <tj@kernel.org>,
Christoph Lameter <cl@gentwo.org>
Cc: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
linux-mm@kvack.org, Eugene Mavick <m@mavick.dev>
Subject: [PATCH v2 0/5] tracing: add ref_trace_final_put tracing
Date: Fri, 10 Jul 2026 13:30:38 +0800 [thread overview]
Message-ID: <20260710-refcount-final-put-trace-v2-0-557cfce860a2@mavick.dev> (raw)
When debugging use-after-free(UAF) bugs, knowing when the object reaches
0 references and enters final release can significantly aid the
debugging process.
There is currently no universal way to trace this information.
This patch series implements tracing of the final puts in the
most widely used refcounting implementations,
refcount_t(and thus kref which uses it), and percpu-ref.
The tracepoint records three fields:
- caller: function that called the refcounting
function(refcount_sub_and_test, percpu_ref_put_many)
- fn: refcounting function(eg refcount_sub_and_test)
- obj: refcount object(struct percpu_ref, refcount_t)
Signed-off-by: Eugene Mavick <m@mavick.dev>
---
Changes in v2:
-include/linux/ref_trace.h: change macro name, use direct tracepoint
call in macro to avoid double check
-add tracepoint to refcount_dec_if_one
-kunit: make significant improvements to design, fix critical bug, add test case for
refcount_dec_if_one()
-Link to v1: https://lore.kernel.org/r/20260705-refcount-final-put-trace-v1-0-0ae936edb750@mavick.dev
---
Eugene Mavick (5):
tracing: add ref_trace_final_put tracepoint
refcount: add ref_trace_final_put tracepoint
percpu-refcount: add ref_trace_final_put trace
kunit: add test for ref_trace_final_put
MAINTAINERS: add entries for ref_trace_final_put
MAINTAINERS | 3 +
include/linux/percpu-refcount.h | 5 +-
include/linux/ref_trace.h | 26 ++++++++
include/linux/refcount.h | 2 +
include/trace/events/ref_trace.h | 46 +++++++++++++
lib/Kconfig | 10 +++
lib/Makefile | 2 +
lib/ref_trace.c | 12 ++++
lib/refcount.c | 8 ++-
lib/tests/Makefile | 1 +
lib/tests/ref_trace_kunit.c | 136 +++++++++++++++++++++++++++++++++++++++
11 files changed, 249 insertions(+), 2 deletions(-)
---
base-commit: df685633c3dbc67441cc86f1c3fee58de4652ba2
change-id: 20260624-refcount-final-put-trace-49bd7c39bd5a
Best regards,
--
Eugene Mavick <m@mavick.dev>
next reply other threads:[~2026-07-10 5:31 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-10 5:30 Eugene Mavick via B4 Relay [this message]
2026-07-10 5:30 ` [PATCH v2 1/5] tracing: add ref_trace_final_put tracepoint Eugene Mavick via B4 Relay
2026-07-10 5:30 ` [PATCH v2 2/5] refcount: " Eugene Mavick via B4 Relay
2026-07-10 5:30 ` [PATCH v2 3/5] percpu-refcount: add ref_trace_final_put trace Eugene Mavick via B4 Relay
2026-07-10 5:30 ` [PATCH v2 4/5] kunit: add test for ref_trace_final_put Eugene Mavick via B4 Relay
2026-07-10 5:30 ` [PATCH v2 5/5] MAINTAINERS: add entries " Eugene Mavick via B4 Relay
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