From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eugene Mavick Date: Fri, 10 Jul 2026 13:30:40 +0800 Subject: [PATCH v2 2/5] refcount: add ref_trace_final_put tracepoint MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260710-refcount-final-put-trace-v2-2-557cfce860a2@mavick.dev> References: <20260710-refcount-final-put-trace-v2-0-557cfce860a2@mavick.dev> In-Reply-To: <20260710-refcount-final-put-trace-v2-0-557cfce860a2@mavick.dev> 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@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-mm@kvack.org, Eugene Mavick X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=openpgp-sha256; l=1880; i=m@mavick.dev; h=from:subject:message-id; bh=LlgAKLvSTzT+rMKMAXMt37/mjMTpw1NXPXF0CRuqRZw=; b=owGbwMvMwCU2V/5U3e1aE3/G02pJDFkBzT33jpy6k7R1+kNdW73wjXUfb26Iv7hoxdSVcvOmh rm/cvrs2VHKwiDGxSArpshSk5XgnrFyVqLx0Uk9MHNYmUCGMHBxCsBEnKMYGVab93IpL7he/jLA ddYj7ctyQnPDJzFeuLVL5dQpt+0l9UUM/4NabsonXO9+eaX0QMPN2z0a//MWS3reFtgW57Lj7cd mBTYA X-Developer-Key: i=m@mavick.dev; a=openpgp; fpr=7C6A604768A99A6133C5928C9D1FCA7EDB7D344F X-Endpoint-Received: by B4 Relay for m@mavick.dev/default with auth_id=850 List-Id: B4 Relay Submissions Add the ref_trace_final_put tracepoint to __refcount_sub_and_test() and refcount_dec_if_one() This tracepoint fires when a refcount_t reaches zero, capturing the caller address, the function name, and the refcount_t address. Signed-off-by: Eugene Mavick --- v2: -update commit message -add tracepoint to refcount_dec_if_one(), suggested by Usuma Arif -move MAINTAINERS file entries to new MAINTAINERS commit -v1:https://lore.kernel.org/all/20260705-refcount-final-put-trace-v1-2-cdd0014626a9@mavick.dev/ --- include/linux/refcount.h | 2 ++ lib/refcount.c | 8 +++++++- 2 files changed, 9 insertions(+), 1 deletion(-) diff --git a/include/linux/refcount.h b/include/linux/refcount.h index ba7657ced281..70d07a462da1 100644 --- a/include/linux/refcount.h +++ b/include/linux/refcount.h @@ -107,6 +107,7 @@ #include #include #include +#include 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(); + do_trace_ref_final_put(r); return true; } diff --git a/lib/refcount.c b/lib/refcount.c index a207a8f22b3c..cd7e32df3919 100644 --- a/lib/refcount.c +++ b/lib/refcount.c @@ -7,6 +7,7 @@ #include #include #include +#include #define REFCOUNT_WARN(str) WARN_ONCE(1, "refcount_t: " str ".\n") @@ -56,7 +57,12 @@ bool refcount_dec_if_one(refcount_t *r) { int val = 1; - return atomic_try_cmpxchg_release(&r->refs, &val, 0); + bool ret = atomic_try_cmpxchg_release(&r->refs, &val, 0); + + if (ret) + do_trace_ref_final_put(r); + + return ret; } EXPORT_SYMBOL(refcount_dec_if_one); -- 2.51.2