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[188.141.5.72]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-48a822be9b4sm38410345e9.9.2026.04.29.22.35.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 29 Apr 2026 22:35:15 -0700 (PDT) From: David Carlier To: linux-trace-kernel@vger.kernel.org Cc: linux-kernel@vger.kernel.org, David Carlier , "Vineeth Pillai (Google)" , Mathieu Desnoyers , Masami Hiramatsu , Peter Zijlstra , Steven Rostedt Subject: [PATCH] tracepoint: add lockdep rcu_is_watching() check to trace_call__##name() Date: Thu, 30 Apr 2026 06:35:10 +0100 Message-ID: <20260430053511.8767-1-devnexen@gmail.com> X-Mailer: git-send-email 2.53.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit trace_call__##name() was added by commit 677a3d82b640 ("tracepoint: Add trace_call__##name() API") to let callers that already gate on trace_##name##_enabled() skip the redundant static_branch_unlikely() re-evaluation. The changelog states that the new helper retains the LOCKDEP RCU-watching assertion carried by trace_##name(), but the WARN_ONCE() was omitted from both definitions. Without it, sites converted from trace_foo(args) to trace_call__foo(args) lose the WARN_ONCE(!rcu_is_watching()) coverage under CONFIG_LOCKDEP when the tracepoint is enabled - the case that commit c2679254b9c9 ("tracing: Make tracepoint lockdep check actually test something") added the warning for. Mirror the same block in both trace_call__##name() bodies, gated by (cond) in __DECLARE_TRACE to match its trace_##name() and ungated in __DECLARE_TRACE_SYSCALL. Fixes: 677a3d82b640 ("tracepoint: Add trace_call__##name() API") Cc: Vineeth Pillai (Google) Cc: Mathieu Desnoyers Cc: Masami Hiramatsu Cc: Peter Zijlstra Signed-off-by: David Carlier --- include/linux/tracepoint.h | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h index 578e520b6ee6..048e0035d4fa 100644 --- a/include/linux/tracepoint.h +++ b/include/linux/tracepoint.h @@ -318,6 +318,10 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) static inline void trace_call__##name(proto) \ { \ __do_trace_##name(args); \ + if (IS_ENABLED(CONFIG_LOCKDEP) && (cond)) { \ + WARN_ONCE(!rcu_is_watching(), \ + "RCU not watching for tracepoint"); \ + } \ } #define __DECLARE_TRACE_SYSCALL(name, proto, args, data_proto) \ @@ -342,6 +346,10 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) { \ might_fault(); \ __do_trace_##name(args); \ + if (IS_ENABLED(CONFIG_LOCKDEP)) { \ + WARN_ONCE(!rcu_is_watching(), \ + "RCU not watching for tracepoint"); \ + } \ } /* -- 2.53.0