linux-kernel - [PATCH v2] tracing: Clean up use of trace_create_maxlat

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20260206230410.4ed96e9f@robin>
Date: Fri, 6 Feb 2026 23:04:10 -0500
From: Steven Rostedt <rostedt@...dmis.org>
To: LKML <linux-kernel@...r.kernel.org>, Linux trace kernel
 <linux-trace-kernel@...r.kernel.org>
Cc: Masami Hiramatsu <mhiramat@...nel.org>, Mathieu Desnoyers
 <mathieu.desnoyers@...icios.com>
Subject: [PATCH v2] tracing: Clean up use of trace_create_maxlat_file()

From: Steven Rostedt <rostedt@...dmis.org>

In trace.c, the function trace_create_maxlat_file() is defined behind the
 #ifdef CONFIG_TRACER_MAX_TRACE block. The #else part defines it as:

 #define trace_create_maxlat_file(tr, d_tracer)				\
	trace_create_file("tracing_max_latency", TRACE_MODE_WRITE,	\
			  d_tracer, tr, &tracing_max_lat_fops)

But the one place that it it used has:

 #ifdef CONFIG_TRACER_MAX_TRACE
	trace_create_maxlat_file(tr, d_tracer);
 #endif

Which is pointless.

Define trace_create_maxlat_file() when CONFIG_TRACER_MAX_TRACE is not
defined as:

 static inline void trace_create_maxlat_file(struct trace_array *tr,
				     struct dentry *d_tracer) { }

And remove the #ifdef's from the code.

Signed-off-by: Steven Rostedt (Google) <rostedt@...dmis.org>
---
Changes since v1: https://patch.msgid.link/20260206121242.6cb1934d@gandalf.local.home

- Fix stub function missing from !CONFIG_TRACER_MAX_TRACE

 kernel/trace/trace.c | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 6815df23e5a3..b59c237f463c 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1969,11 +1969,8 @@ void latency_fsnotify(struct trace_array *tr)
 }
 
 #else /* !LATENCY_FS_NOTIFY */
-
-#define trace_create_maxlat_file(tr, d_tracer)				\
-	trace_create_file("tracing_max_latency", TRACE_MODE_WRITE,	\
-			  d_tracer, tr, &tracing_max_lat_fops)
-
+static inline void trace_create_maxlat_file(struct trace_array *tr,
+					    struct dentry *d_tracer) { }
 #endif
 
 /*
@@ -2109,7 +2106,9 @@ update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
 	__update_max_tr(tr, tsk, cpu);
 	arch_spin_unlock(&tr->max_lock);
 }
-
+#else
+static inline void trace_create_maxlat_file(struct trace_array *tr,
+					    struct dentry *d_tracer) { }
 #endif /* CONFIG_TRACER_MAX_TRACE */
 
 struct pipe_wait {
@@ -10684,9 +10683,7 @@ init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer)
 
 	create_trace_options_dir(tr);
 
-#ifdef CONFIG_TRACER_MAX_TRACE
 	trace_create_maxlat_file(tr, d_tracer);
-#endif
 
 	if (ftrace_create_function_files(tr, d_tracer))
 		MEM_FAIL(1, "Could not allocate function filter files");
-- 
2.51.0