[PATCH v2 0/2] tracing: Remove trace_printk.h from kernel.h

[PATCH v2 0/2] tracing: Remove trace_printk.h from kernel.h

[Steven Rostedt]

Remove trace_printk.h by creating a trace_controls.h for those places that
need access to tracing prototypes like tracing_off() and for the places that
need trace_printk() directly, to have it included directly.

Changse since v1: https://lore.kernel.org/all/20260621093430.264983361@kernel.org/

- Create a trace_controls.h header to move the prototypes into and not
  include it back into kernel.h

- Just remove trace_printk.h from kernel.h with no alternative to keep the
  previous behavior.

Steven Rostedt (2):
      tracing: Move non-trace_printk prototypes into trace_controls.h
      tracing: Remove trace_printk.h from kernel.h

----
 arch/powerpc/kvm/book3s_xics.c         |  1 +
 arch/powerpc/xmon/xmon.c               |  1 +
 arch/s390/kernel/ipl.c                 |  1 +
 arch/s390/kernel/machine_kexec.c       |  1 +
 drivers/gpu/drm/i915/gt/intel_gtt.h    |  1 +
 drivers/gpu/drm/i915/i915_gem.h        |  2 ++
 drivers/hwtracing/stm/dummy_stm.c      |  4 +++
 drivers/infiniband/hw/hfi1/trace_dbg.h |  1 +
 drivers/tty/sysrq.c                    |  1 +
 drivers/usb/early/xhci-dbc.c           |  1 +
 fs/ext4/inline.c                       |  1 +
 include/linux/ftrace.h                 |  2 ++
 include/linux/kernel.h                 |  1 -
 include/linux/sunrpc/debug.h           |  1 +
 include/linux/trace_controls.h         | 54 ++++++++++++++++++++++++++++++++
 include/linux/trace_printk.h           | 56 ++--------------------------------
 kernel/debug/debug_core.c              |  1 +
 kernel/panic.c                         |  1 +
 kernel/rcu/rcu.h                       |  2 ++
 kernel/rcu/rcutorture.c                |  1 +
 kernel/trace/ring_buffer_benchmark.c   |  1 +
 kernel/trace/trace.h                   |  1 +
 kernel/trace/trace_benchmark.c         |  1 +
 lib/sys_info.c                         |  1 +
 samples/fprobe/fprobe_example.c        |  1 +
 samples/ftrace/ftrace-direct-too.c     |  1 -
 samples/trace_printk/trace-printk.c    |  1 +
 27 files changed, 86 insertions(+), 55 deletions(-)
 create mode 100644 include/linux/trace_controls.h

[PATCH v2 1/2] tracing: Move non-trace_printk prototypes into trace_controls.h

[Steven Rostedt]

From: Steven Rostedt <rostedt@goodmis.org>

In order to remove the include to trace_printk.h from kernel.h the tracing
control prototypes need to be separated into their own header file as they
are used in other common header files like rcu.h. There's no point in
removing trace_printk.h from kernel.h if it just gets added back to other
common headers.

Prototypes are very cheap for the compiler and should not be an issue.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
Changes since v1: https://patch.msgid.link/20260621093811.007634476@kernel.org

- Instead of moving back into kernel.h, create a new trace_controls.h
  header.

 arch/powerpc/xmon/xmon.c         |  1 +
 arch/s390/kernel/ipl.c           |  1 +
 arch/s390/kernel/machine_kexec.c |  1 +
 drivers/gpu/drm/i915/i915_gem.h  |  1 +
 drivers/tty/sysrq.c              |  1 +
 include/linux/trace_controls.h   | 54 ++++++++++++++++++++++++++++++++
 include/linux/trace_printk.h     | 51 ------------------------------
 kernel/debug/debug_core.c        |  1 +
 kernel/panic.c                   |  1 +
 kernel/rcu/rcu.h                 |  2 ++
 kernel/rcu/rcutorture.c          |  1 +
 kernel/trace/trace.h             |  1 +
 kernel/trace/trace_benchmark.c   |  1 +
 lib/sys_info.c                   |  1 +
 14 files changed, 67 insertions(+), 51 deletions(-)
 create mode 100644 include/linux/trace_controls.h

diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index cb3a3244ae6f..2135f319e0dd 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -27,6 +27,7 @@
 #include <linux/highmem.h>
 #include <linux/security.h>
 #include <linux/debugfs.h>
+#include <linux/trace_controls.h>
 
 #include <asm/ptrace.h>
 #include <asm/smp.h>
diff --git a/arch/s390/kernel/ipl.c b/arch/s390/kernel/ipl.c
index 3c346b02ceb9..baac66cc4de4 100644
--- a/arch/s390/kernel/ipl.c
+++ b/arch/s390/kernel/ipl.c
@@ -22,6 +22,7 @@
 #include <linux/debug_locks.h>
 #include <linux/vmalloc.h>
 #include <linux/secure_boot.h>
+#include <linux/trace_controls.h>
 #include <asm/asm-extable.h>
 #include <asm/machine.h>
 #include <asm/diag.h>
diff --git a/arch/s390/kernel/machine_kexec.c b/arch/s390/kernel/machine_kexec.c
index baeb3dcfc1c8..33f9a89eb3ad 100644
--- a/arch/s390/kernel/machine_kexec.c
+++ b/arch/s390/kernel/machine_kexec.c
@@ -12,6 +12,7 @@
 #include <linux/delay.h>
 #include <linux/reboot.h>
 #include <linux/ftrace.h>
+#include <linux/trace_controls.h>
 #include <linux/debug_locks.h>
 #include <linux/cpufeature.h>
 #include <asm/guarded_storage.h>
diff --git a/drivers/gpu/drm/i915/i915_gem.h b/drivers/gpu/drm/i915/i915_gem.h
index 20b3cb29cfff..1da8fb61c09e 100644
--- a/drivers/gpu/drm/i915/i915_gem.h
+++ b/drivers/gpu/drm/i915/i915_gem.h
@@ -116,6 +116,7 @@ int i915_gem_open(struct drm_i915_private *i915, struct drm_file *file);
 #endif
 
 #if IS_ENABLED(CONFIG_DRM_I915_TRACE_GEM)
+#include <linux/trace_controls.h>
 #define GEM_TRACE(...) trace_printk(__VA_ARGS__)
 #define GEM_TRACE_ERR(...) do {						\
 	pr_err(__VA_ARGS__);						\
diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c
index c2e4b31b699a..d3f72dc430b8 100644
--- a/drivers/tty/sysrq.c
+++ b/drivers/tty/sysrq.c
@@ -324,6 +324,7 @@ static const struct sysrq_key_op sysrq_showstate_blocked_op = {
 };
 
 #ifdef CONFIG_TRACING
+#include <linux/trace_controls.h>
 #include <linux/ftrace.h>
 
 static void sysrq_ftrace_dump(u8 key)
diff --git a/include/linux/trace_controls.h b/include/linux/trace_controls.h
new file mode 100644
index 000000000000..995b97e963b4
--- /dev/null
+++ b/include/linux/trace_controls.h
@@ -0,0 +1,54 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_TRACE_CONTROLS_H
+#define _LINUX_TRACE_CONTROLS_H
+
+
+/*
+ * General tracing related utility functions - trace_printk(),
+ * tracing_on/tracing_off and tracing_start()/tracing_stop
+ *
+ * Use tracing_on/tracing_off when you want to quickly turn on or off
+ * tracing. It simply enables or disables the recording of the trace events.
+ * This also corresponds to the user space /sys/kernel/tracing/tracing_on
+ * file, which gives a means for the kernel and userspace to interact.
+ * Place a tracing_off() in the kernel where you want tracing to end.
+ * From user space, examine the trace, and then echo 1 > tracing_on
+ * to continue tracing.
+ *
+ * tracing_stop/tracing_start has slightly more overhead. It is used
+ * by things like suspend to ram where disabling the recording of the
+ * trace is not enough, but tracing must actually stop because things
+ * like calling smp_processor_id() may crash the system.
+ *
+ * Most likely, you want to use tracing_on/tracing_off.
+ */
+enum ftrace_dump_mode {
+	DUMP_NONE,
+	DUMP_ALL,
+	DUMP_ORIG,
+	DUMP_PARAM,
+};
+
+#ifdef CONFIG_TRACING
+void tracing_on(void);
+void tracing_off(void);
+int tracing_is_on(void);
+void tracing_snapshot(void);
+void tracing_snapshot_alloc(void);
+void tracing_start(void);
+void tracing_stop(void);
+void trace_dump_stack(int skip);
+void ftrace_dump(enum ftrace_dump_mode oops_dump_mode);
+#else
+static inline void tracing_start(void) { }
+static inline void tracing_stop(void) { }
+static inline void tracing_on(void) { }
+static inline void tracing_off(void) { }
+static inline int tracing_is_on(void) { return 0; }
+static inline void tracing_snapshot(void) { }
+static inline void tracing_snapshot_alloc(void) { }
+static inline void trace_dump_stack(int skip) { }
+static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
+#endif
+
+#endif /* _LINUX_TRACE_CONTROLS_H */
diff --git a/include/linux/trace_printk.h b/include/linux/trace_printk.h
index 3d54f440dccf..a488ea9e9f85 100644
--- a/include/linux/trace_printk.h
+++ b/include/linux/trace_printk.h
@@ -7,43 +7,7 @@
 #include <linux/stddef.h>
 #include <linux/stringify.h>
 
-/*
- * General tracing related utility functions - trace_printk(),
- * tracing_on/tracing_off and tracing_start()/tracing_stop
- *
- * Use tracing_on/tracing_off when you want to quickly turn on or off
- * tracing. It simply enables or disables the recording of the trace events.
- * This also corresponds to the user space /sys/kernel/tracing/tracing_on
- * file, which gives a means for the kernel and userspace to interact.
- * Place a tracing_off() in the kernel where you want tracing to end.
- * From user space, examine the trace, and then echo 1 > tracing_on
- * to continue tracing.
- *
- * tracing_stop/tracing_start has slightly more overhead. It is used
- * by things like suspend to ram where disabling the recording of the
- * trace is not enough, but tracing must actually stop because things
- * like calling smp_processor_id() may crash the system.
- *
- * Most likely, you want to use tracing_on/tracing_off.
- */
-
-enum ftrace_dump_mode {
-	DUMP_NONE,
-	DUMP_ALL,
-	DUMP_ORIG,
-	DUMP_PARAM,
-};
-
 #ifdef CONFIG_TRACING
-void tracing_on(void);
-void tracing_off(void);
-int tracing_is_on(void);
-void tracing_snapshot(void);
-void tracing_snapshot_alloc(void);
-
-extern void tracing_start(void);
-extern void tracing_stop(void);
-
 static inline __printf(1, 2)
 void ____trace_printk_check_format(const char *fmt, ...)
 {
@@ -149,8 +113,6 @@ int __trace_printk(unsigned long ip, const char *fmt, ...);
 extern int __trace_bputs(unsigned long ip, const char *str);
 extern int __trace_puts(unsigned long ip, const char *str);
 
-extern void trace_dump_stack(int skip);
-
 /*
  * The double __builtin_constant_p is because gcc will give us an error
  * if we try to allocate the static variable to fmt if it is not a
@@ -173,19 +135,7 @@ __ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap);
 
 extern __printf(2, 0) int
 __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
-
-extern void ftrace_dump(enum ftrace_dump_mode oops_dump_mode);
 #else
-static inline void tracing_start(void) { }
-static inline void tracing_stop(void) { }
-static inline void trace_dump_stack(int skip) { }
-
-static inline void tracing_on(void) { }
-static inline void tracing_off(void) { }
-static inline int tracing_is_on(void) { return 0; }
-static inline void tracing_snapshot(void) { }
-static inline void tracing_snapshot_alloc(void) { }
-
 static inline __printf(1, 2)
 int trace_printk(const char *fmt, ...)
 {
@@ -196,7 +146,6 @@ ftrace_vprintk(const char *fmt, va_list ap)
 {
 	return 0;
 }
-static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
 #endif /* CONFIG_TRACING */
 
 #endif
diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c
index b276504c1c6b..f9c83a470c98 100644
--- a/kernel/debug/debug_core.c
+++ b/kernel/debug/debug_core.c
@@ -27,6 +27,7 @@
 
 #define pr_fmt(fmt) "KGDB: " fmt
 
+#include <linux/trace_controls.h>
 #include <linux/pid_namespace.h>
 #include <linux/clocksource.h>
 #include <linux/serial_core.h>
diff --git a/kernel/panic.c b/kernel/panic.c
index 213725b612aa..1415e910371d 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -9,6 +9,7 @@
  * This function is used through-out the kernel (including mm and fs)
  * to indicate a major problem.
  */
+#include <linux/trace_controls.h>
 #include <linux/debug_locks.h>
 #include <linux/sched/debug.h>
 #include <linux/interrupt.h>
diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h
index fa6d30ce73d1..b3e2c8f25a4f 100644
--- a/kernel/rcu/rcu.h
+++ b/kernel/rcu/rcu.h
@@ -280,6 +280,8 @@ extern int rcu_cpu_stall_notifiers;
 
 #ifdef CONFIG_RCU_STALL_COMMON
 
+#include <linux/trace_controls.h>
+
 extern int rcu_cpu_stall_ftrace_dump;
 extern int rcu_cpu_stall_suppress;
 extern int rcu_cpu_stall_timeout;
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index 882a158ada7b..76bf0184b267 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -39,6 +39,7 @@
 #include <linux/srcu.h>
 #include <linux/slab.h>
 #include <linux/trace_clock.h>
+#include <linux/trace_controls.h>
 #include <asm/byteorder.h>
 #include <linux/torture.h>
 #include <linux/vmalloc.h>
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 80fe152af1dd..2537c33ddd49 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -22,6 +22,7 @@
 #include <linux/ctype.h>
 #include <linux/once_lite.h>
 #include <linux/ftrace_regs.h>
+#include <linux/trace_controls.h>
 #include <linux/llist.h>
 
 #include "pid_list.h"
diff --git a/kernel/trace/trace_benchmark.c b/kernel/trace/trace_benchmark.c
index e19c32f2a938..69cc39008c36 100644
--- a/kernel/trace/trace_benchmark.c
+++ b/kernel/trace/trace_benchmark.c
@@ -3,6 +3,7 @@
 #include <linux/module.h>
 #include <linux/kthread.h>
 #include <linux/trace_clock.h>
+#include <linux/trace_controls.h>
 
 #define CREATE_TRACE_POINTS
 #include "trace_benchmark.h"
diff --git a/lib/sys_info.c b/lib/sys_info.c
index f32a06ec9ed4..e3c9ca05601b 100644
--- a/lib/sys_info.c
+++ b/lib/sys_info.c
@@ -8,6 +8,7 @@
 #include <linux/ftrace.h>
 #include <linux/nmi.h>
 #include <linux/sched/debug.h>
+#include <linux/trace_controls.h>
 #include <linux/string.h>
 #include <linux/sysctl.h>
 
-- 
2.53.0

Re: [PATCH v2 1/2] tracing: Move non-trace_printk prototypes into trace_controls.h

[Yury Norov]

On Mon, Jun 22, 2026 at 09:07:40AM -0400, Steven Rostedt wrote:
> From: Steven Rostedt <rostedt@goodmis.org>
> 
> In order to remove the include to trace_printk.h from kernel.h the tracing
> control prototypes need to be separated into their own header file as they
> are used in other common header files like rcu.h. There's no point in
> removing trace_printk.h from kernel.h if it just gets added back to other
> common headers.
> 
> Prototypes are very cheap for the compiler and should not be an issue.
> 
> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

Suggested-by: Yury Norov <yury.norov@gmail.com>

> ---
> Changes since v1: https://patch.msgid.link/20260621093811.007634476@kernel.org
> 
> - Instead of moving back into kernel.h, create a new trace_controls.h
>   header.
> 
>  arch/powerpc/xmon/xmon.c         |  1 +
>  arch/s390/kernel/ipl.c           |  1 +
>  arch/s390/kernel/machine_kexec.c |  1 +
>  drivers/gpu/drm/i915/i915_gem.h  |  1 +
>  drivers/tty/sysrq.c              |  1 +
>  include/linux/trace_controls.h   | 54 ++++++++++++++++++++++++++++++++
>  include/linux/trace_printk.h     | 51 ------------------------------
>  kernel/debug/debug_core.c        |  1 +
>  kernel/panic.c                   |  1 +
>  kernel/rcu/rcu.h                 |  2 ++
>  kernel/rcu/rcutorture.c          |  1 +
>  kernel/trace/trace.h             |  1 +
>  kernel/trace/trace_benchmark.c   |  1 +
>  lib/sys_info.c                   |  1 +
>  14 files changed, 67 insertions(+), 51 deletions(-)
>  create mode 100644 include/linux/trace_controls.h
> 
> diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
> index cb3a3244ae6f..2135f319e0dd 100644
> --- a/arch/powerpc/xmon/xmon.c
> +++ b/arch/powerpc/xmon/xmon.c
> @@ -27,6 +27,7 @@
>  #include <linux/highmem.h>
>  #include <linux/security.h>
>  #include <linux/debugfs.h>
> +#include <linux/trace_controls.h>
>  
>  #include <asm/ptrace.h>
>  #include <asm/smp.h>
> diff --git a/arch/s390/kernel/ipl.c b/arch/s390/kernel/ipl.c
> index 3c346b02ceb9..baac66cc4de4 100644
> --- a/arch/s390/kernel/ipl.c
> +++ b/arch/s390/kernel/ipl.c
> @@ -22,6 +22,7 @@
>  #include <linux/debug_locks.h>
>  #include <linux/vmalloc.h>
>  #include <linux/secure_boot.h>
> +#include <linux/trace_controls.h>
>  #include <asm/asm-extable.h>
>  #include <asm/machine.h>
>  #include <asm/diag.h>
> diff --git a/arch/s390/kernel/machine_kexec.c b/arch/s390/kernel/machine_kexec.c
> index baeb3dcfc1c8..33f9a89eb3ad 100644
> --- a/arch/s390/kernel/machine_kexec.c
> +++ b/arch/s390/kernel/machine_kexec.c
> @@ -12,6 +12,7 @@
>  #include <linux/delay.h>
>  #include <linux/reboot.h>
>  #include <linux/ftrace.h>
> +#include <linux/trace_controls.h>
>  #include <linux/debug_locks.h>
>  #include <linux/cpufeature.h>
>  #include <asm/guarded_storage.h>
> diff --git a/drivers/gpu/drm/i915/i915_gem.h b/drivers/gpu/drm/i915/i915_gem.h
> index 20b3cb29cfff..1da8fb61c09e 100644
> --- a/drivers/gpu/drm/i915/i915_gem.h
> +++ b/drivers/gpu/drm/i915/i915_gem.h
> @@ -116,6 +116,7 @@ int i915_gem_open(struct drm_i915_private *i915, struct drm_file *file);
>  #endif
>  
>  #if IS_ENABLED(CONFIG_DRM_I915_TRACE_GEM)
> +#include <linux/trace_controls.h>
>  #define GEM_TRACE(...) trace_printk(__VA_ARGS__)
>  #define GEM_TRACE_ERR(...) do {						\
>  	pr_err(__VA_ARGS__);						\
> diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c
> index c2e4b31b699a..d3f72dc430b8 100644
> --- a/drivers/tty/sysrq.c
> +++ b/drivers/tty/sysrq.c
> @@ -324,6 +324,7 @@ static const struct sysrq_key_op sysrq_showstate_blocked_op = {
>  };
>  
>  #ifdef CONFIG_TRACING
> +#include <linux/trace_controls.h>
>  #include <linux/ftrace.h>
>  
>  static void sysrq_ftrace_dump(u8 key)
> diff --git a/include/linux/trace_controls.h b/include/linux/trace_controls.h
> new file mode 100644
> index 000000000000..995b97e963b4
> --- /dev/null
> +++ b/include/linux/trace_controls.h
> @@ -0,0 +1,54 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef _LINUX_TRACE_CONTROLS_H
> +#define _LINUX_TRACE_CONTROLS_H
> +
> +
> +/*
> + * General tracing related utility functions - trace_printk(),
> + * tracing_on/tracing_off and tracing_start()/tracing_stop
> + *
> + * Use tracing_on/tracing_off when you want to quickly turn on or off
> + * tracing. It simply enables or disables the recording of the trace events.
> + * This also corresponds to the user space /sys/kernel/tracing/tracing_on
> + * file, which gives a means for the kernel and userspace to interact.
> + * Place a tracing_off() in the kernel where you want tracing to end.
> + * From user space, examine the trace, and then echo 1 > tracing_on
> + * to continue tracing.
> + *
> + * tracing_stop/tracing_start has slightly more overhead. It is used
> + * by things like suspend to ram where disabling the recording of the
> + * trace is not enough, but tracing must actually stop because things
> + * like calling smp_processor_id() may crash the system.
> + *
> + * Most likely, you want to use tracing_on/tracing_off.
> + */
> +enum ftrace_dump_mode {
> +	DUMP_NONE,
> +	DUMP_ALL,
> +	DUMP_ORIG,
> +	DUMP_PARAM,
> +};
> +
> +#ifdef CONFIG_TRACING
> +void tracing_on(void);
> +void tracing_off(void);
> +int tracing_is_on(void);
> +void tracing_snapshot(void);
> +void tracing_snapshot_alloc(void);
> +void tracing_start(void);
> +void tracing_stop(void);
> +void trace_dump_stack(int skip);

The function description says:

  record a stack back trace in the trace buffer

So, to me it sounds like it should go to the trace_printk.h.

> +void ftrace_dump(enum ftrace_dump_mode oops_dump_mode);

Same here, based on the function name, it relates to ftrace.h, not the
tracing control itself.

For example, lib/sys_info.c only calls ftrace_dump, and already
includes ftrace.h. If you place ftrace_dump() as suggested, you can
include only ftrace.h in there, and don't include trace_printk.h and
trace_control.h

Thanks,
Yury

> +#else
> +static inline void tracing_start(void) { }
> +static inline void tracing_stop(void) { }
> +static inline void tracing_on(void) { }
> +static inline void tracing_off(void) { }
> +static inline int tracing_is_on(void) { return 0; }
> +static inline void tracing_snapshot(void) { }
> +static inline void tracing_snapshot_alloc(void) { }
> +static inline void trace_dump_stack(int skip) { }
> +static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
> +#endif
> +
> +#endif /* _LINUX_TRACE_CONTROLS_H */
> diff --git a/include/linux/trace_printk.h b/include/linux/trace_printk.h
> index 3d54f440dccf..a488ea9e9f85 100644
> --- a/include/linux/trace_printk.h
> +++ b/include/linux/trace_printk.h
> @@ -7,43 +7,7 @@
>  #include <linux/stddef.h>
>  #include <linux/stringify.h>
>  
> -/*
> - * General tracing related utility functions - trace_printk(),
> - * tracing_on/tracing_off and tracing_start()/tracing_stop
> - *
> - * Use tracing_on/tracing_off when you want to quickly turn on or off
> - * tracing. It simply enables or disables the recording of the trace events.
> - * This also corresponds to the user space /sys/kernel/tracing/tracing_on
> - * file, which gives a means for the kernel and userspace to interact.
> - * Place a tracing_off() in the kernel where you want tracing to end.
> - * From user space, examine the trace, and then echo 1 > tracing_on
> - * to continue tracing.
> - *
> - * tracing_stop/tracing_start has slightly more overhead. It is used
> - * by things like suspend to ram where disabling the recording of the
> - * trace is not enough, but tracing must actually stop because things
> - * like calling smp_processor_id() may crash the system.
> - *
> - * Most likely, you want to use tracing_on/tracing_off.
> - */
> -
> -enum ftrace_dump_mode {
> -	DUMP_NONE,
> -	DUMP_ALL,
> -	DUMP_ORIG,
> -	DUMP_PARAM,
> -};
> -
>  #ifdef CONFIG_TRACING
> -void tracing_on(void);
> -void tracing_off(void);
> -int tracing_is_on(void);
> -void tracing_snapshot(void);
> -void tracing_snapshot_alloc(void);
> -
> -extern void tracing_start(void);
> -extern void tracing_stop(void);
> -
>  static inline __printf(1, 2)
>  void ____trace_printk_check_format(const char *fmt, ...)
>  {
> @@ -149,8 +113,6 @@ int __trace_printk(unsigned long ip, const char *fmt, ...);
>  extern int __trace_bputs(unsigned long ip, const char *str);
>  extern int __trace_puts(unsigned long ip, const char *str);
>  
> -extern void trace_dump_stack(int skip);
> -
>  /*
>   * The double __builtin_constant_p is because gcc will give us an error
>   * if we try to allocate the static variable to fmt if it is not a
> @@ -173,19 +135,7 @@ __ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap);
>  
>  extern __printf(2, 0) int
>  __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
> -
> -extern void ftrace_dump(enum ftrace_dump_mode oops_dump_mode);
>  #else
> -static inline void tracing_start(void) { }
> -static inline void tracing_stop(void) { }
> -static inline void trace_dump_stack(int skip) { }
> -
> -static inline void tracing_on(void) { }
> -static inline void tracing_off(void) { }
> -static inline int tracing_is_on(void) { return 0; }
> -static inline void tracing_snapshot(void) { }
> -static inline void tracing_snapshot_alloc(void) { }
> -
>  static inline __printf(1, 2)
>  int trace_printk(const char *fmt, ...)
>  {
> @@ -196,7 +146,6 @@ ftrace_vprintk(const char *fmt, va_list ap)
>  {
>  	return 0;
>  }
> -static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
>  #endif /* CONFIG_TRACING */
>  
>  #endif
> diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c
> index b276504c1c6b..f9c83a470c98 100644
> --- a/kernel/debug/debug_core.c
> +++ b/kernel/debug/debug_core.c
> @@ -27,6 +27,7 @@
>  
>  #define pr_fmt(fmt) "KGDB: " fmt
>  
> +#include <linux/trace_controls.h>
>  #include <linux/pid_namespace.h>
>  #include <linux/clocksource.h>
>  #include <linux/serial_core.h>
> diff --git a/kernel/panic.c b/kernel/panic.c
> index 213725b612aa..1415e910371d 100644
> --- a/kernel/panic.c
> +++ b/kernel/panic.c
> @@ -9,6 +9,7 @@
>   * This function is used through-out the kernel (including mm and fs)
>   * to indicate a major problem.
>   */
> +#include <linux/trace_controls.h>
>  #include <linux/debug_locks.h>
>  #include <linux/sched/debug.h>
>  #include <linux/interrupt.h>
> diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h
> index fa6d30ce73d1..b3e2c8f25a4f 100644
> --- a/kernel/rcu/rcu.h
> +++ b/kernel/rcu/rcu.h
> @@ -280,6 +280,8 @@ extern int rcu_cpu_stall_notifiers;
>  
>  #ifdef CONFIG_RCU_STALL_COMMON
>  
> +#include <linux/trace_controls.h>
> +
>  extern int rcu_cpu_stall_ftrace_dump;
>  extern int rcu_cpu_stall_suppress;
>  extern int rcu_cpu_stall_timeout;
> diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
> index 882a158ada7b..76bf0184b267 100644
> --- a/kernel/rcu/rcutorture.c
> +++ b/kernel/rcu/rcutorture.c
> @@ -39,6 +39,7 @@
>  #include <linux/srcu.h>
>  #include <linux/slab.h>
>  #include <linux/trace_clock.h>
> +#include <linux/trace_controls.h>
>  #include <asm/byteorder.h>
>  #include <linux/torture.h>
>  #include <linux/vmalloc.h>
> diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
> index 80fe152af1dd..2537c33ddd49 100644
> --- a/kernel/trace/trace.h
> +++ b/kernel/trace/trace.h
> @@ -22,6 +22,7 @@
>  #include <linux/ctype.h>
>  #include <linux/once_lite.h>
>  #include <linux/ftrace_regs.h>
> +#include <linux/trace_controls.h>
>  #include <linux/llist.h>
>  
>  #include "pid_list.h"
> diff --git a/kernel/trace/trace_benchmark.c b/kernel/trace/trace_benchmark.c
> index e19c32f2a938..69cc39008c36 100644
> --- a/kernel/trace/trace_benchmark.c
> +++ b/kernel/trace/trace_benchmark.c
> @@ -3,6 +3,7 @@
>  #include <linux/module.h>
>  #include <linux/kthread.h>
>  #include <linux/trace_clock.h>
> +#include <linux/trace_controls.h>
>  
>  #define CREATE_TRACE_POINTS
>  #include "trace_benchmark.h"
> diff --git a/lib/sys_info.c b/lib/sys_info.c
> index f32a06ec9ed4..e3c9ca05601b 100644
> --- a/lib/sys_info.c
> +++ b/lib/sys_info.c
> @@ -8,6 +8,7 @@
>  #include <linux/ftrace.h>
>  #include <linux/nmi.h>
>  #include <linux/sched/debug.h>
> +#include <linux/trace_controls.h>
>  #include <linux/string.h>
>  #include <linux/sysctl.h>
>  
> -- 
> 2.53.0
> 

Re: [PATCH v2 1/2] tracing: Move non-trace_printk prototypes into trace_controls.h

[Steven Rostedt]

On Mon, 22 Jun 2026 09:41:16 -0400
Yury Norov <yury.norov@gmail.com> wrote:

> On Mon, Jun 22, 2026 at 09:07:40AM -0400, Steven Rostedt wrote:
> > From: Steven Rostedt <rostedt@goodmis.org>
> > 
> > In order to remove the include to trace_printk.h from kernel.h the tracing
> > control prototypes need to be separated into their own header file as they
> > are used in other common header files like rcu.h. There's no point in
> > removing trace_printk.h from kernel.h if it just gets added back to other
> > common headers.
> > 
> > Prototypes are very cheap for the compiler and should not be an issue.
> > 
> > Signed-off-by: Steven Rostedt <rostedt@goodmis.org>  
> 
> Suggested-by: Yury Norov <yury.norov@gmail.com>

Thanks, I'll add you tag.

-- Steve

Re: [PATCH v2 1/2] tracing: Move non-trace_printk prototypes into trace_controls.h

[Yury Norov]

On Mon, Jun 22, 2026 at 11:21:27AM -0400, Steven Rostedt wrote:
> On Mon, 22 Jun 2026 09:41:16 -0400
> Yury Norov <yury.norov@gmail.com> wrote:
> 
> > On Mon, Jun 22, 2026 at 09:07:40AM -0400, Steven Rostedt wrote:
> > > From: Steven Rostedt <rostedt@goodmis.org>
> > > 
> > > In order to remove the include to trace_printk.h from kernel.h the tracing
> > > control prototypes need to be separated into their own header file as they
> > > are used in other common header files like rcu.h. There's no point in
> > > removing trace_printk.h from kernel.h if it just gets added back to other
> > > common headers.
> > > 
> > > Prototypes are very cheap for the compiler and should not be an issue.
> > > 
> > > Signed-off-by: Steven Rostedt <rostedt@goodmis.org>  
> > 
> > Suggested-by: Yury Norov <yury.norov@gmail.com>
> 
> Thanks, I'll add you tag.

Thanks, but can you also comment on trace_dump/ftrace_dump?

[PATCH v2 2/2] tracing: Remove trace_printk.h from kernel.h

[Steven Rostedt]

From: Steven Rostedt <rostedt@goodmis.org>

There have been complaints about trace_printk.h causing more build time
for being in kernel.h. Move it out of kernel.h and place it in the headers
and C files that use it.

Link: https://lore.kernel.org/all/CAHk-=wikCBeVFjVXiY4o-oepdbjAoir5+TcAgtL12c4u1TpZLQ@mail.gmail.com/

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
Changes since v1: https://patch.msgid.link/20260621093811.168514984@kernel.org

- Just remove trace_printk.h and fix up all the places that need it.

 arch/powerpc/kvm/book3s_xics.c         | 1 +
 drivers/gpu/drm/i915/gt/intel_gtt.h    | 1 +
 drivers/gpu/drm/i915/i915_gem.h        | 1 +
 drivers/hwtracing/stm/dummy_stm.c      | 4 ++++
 drivers/infiniband/hw/hfi1/trace_dbg.h | 1 +
 drivers/usb/early/xhci-dbc.c           | 1 +
 fs/ext4/inline.c                       | 1 +
 include/linux/ftrace.h                 | 2 ++
 include/linux/kernel.h                 | 1 -
 include/linux/sunrpc/debug.h           | 1 +
 include/linux/trace_printk.h           | 5 +++--
 kernel/trace/ring_buffer_benchmark.c   | 1 +
 samples/fprobe/fprobe_example.c        | 1 +
 samples/ftrace/ftrace-direct-too.c     | 1 -
 samples/trace_printk/trace-printk.c    | 1 +
 15 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/kvm/book3s_xics.c b/arch/powerpc/kvm/book3s_xics.c
index 74a44fa702b0..ef5eb596a56e 100644
--- a/arch/powerpc/kvm/book3s_xics.c
+++ b/arch/powerpc/kvm/book3s_xics.c
@@ -26,6 +26,7 @@
 #if 1
 #define XICS_DBG(fmt...) do { } while (0)
 #else
+#include <linux/trace_printk.h>
 #define XICS_DBG(fmt...) trace_printk(fmt)
 #endif
 
diff --git a/drivers/gpu/drm/i915/gt/intel_gtt.h b/drivers/gpu/drm/i915/gt/intel_gtt.h
index b54ee4f25af1..f6f223090760 100644
--- a/drivers/gpu/drm/i915/gt/intel_gtt.h
+++ b/drivers/gpu/drm/i915/gt/intel_gtt.h
@@ -35,6 +35,7 @@
 #define I915_GFP_ALLOW_FAIL (GFP_KERNEL | __GFP_RETRY_MAYFAIL | __GFP_NOWARN)
 
 #if IS_ENABLED(CONFIG_DRM_I915_TRACE_GTT)
+#include <linux/trace_printk.h>
 #define GTT_TRACE(...) trace_printk(__VA_ARGS__)
 #else
 #define GTT_TRACE(...)
diff --git a/drivers/gpu/drm/i915/i915_gem.h b/drivers/gpu/drm/i915/i915_gem.h
index 1da8fb61c09e..f490052e8964 100644
--- a/drivers/gpu/drm/i915/i915_gem.h
+++ b/drivers/gpu/drm/i915/i915_gem.h
@@ -117,6 +117,7 @@ int i915_gem_open(struct drm_i915_private *i915, struct drm_file *file);
 
 #if IS_ENABLED(CONFIG_DRM_I915_TRACE_GEM)
 #include <linux/trace_controls.h>
+#include <linux/trace_printk.h>
 #define GEM_TRACE(...) trace_printk(__VA_ARGS__)
 #define GEM_TRACE_ERR(...) do {						\
 	pr_err(__VA_ARGS__);						\
diff --git a/drivers/hwtracing/stm/dummy_stm.c b/drivers/hwtracing/stm/dummy_stm.c
index 38528ffdc0b3..784f9af7ccba 100644
--- a/drivers/hwtracing/stm/dummy_stm.c
+++ b/drivers/hwtracing/stm/dummy_stm.c
@@ -14,6 +14,10 @@
 #include <linux/stm.h>
 #include <uapi/linux/stm.h>
 
+#ifdef DEBUG
+#include <linux/trace_printk.h>
+#endif
+
 static ssize_t notrace
 dummy_stm_packet(struct stm_data *stm_data, unsigned int master,
 		 unsigned int channel, unsigned int packet, unsigned int flags,
diff --git a/drivers/infiniband/hw/hfi1/trace_dbg.h b/drivers/infiniband/hw/hfi1/trace_dbg.h
index 58304b91380f..30df5e246586 100644
--- a/drivers/infiniband/hw/hfi1/trace_dbg.h
+++ b/drivers/infiniband/hw/hfi1/trace_dbg.h
@@ -103,6 +103,7 @@ __hfi1_trace_def(IOCTL);
  */
 
 #ifdef HFI1_EARLY_DBG
+#include <linux/trace_printk.h>
 #define hfi1_dbg_early(fmt, ...) \
 	trace_printk(fmt, ##__VA_ARGS__)
 #else
diff --git a/drivers/usb/early/xhci-dbc.c b/drivers/usb/early/xhci-dbc.c
index 41118bba9197..955c73bd601f 100644
--- a/drivers/usb/early/xhci-dbc.c
+++ b/drivers/usb/early/xhci-dbc.c
@@ -30,6 +30,7 @@ static struct xdbc_state xdbc;
 static bool early_console_keep;
 
 #ifdef XDBC_TRACE
+#include <linux/trace_printk.h>
 #define	xdbc_trace	trace_printk
 #else
 static inline void xdbc_trace(const char *fmt, ...) { }
diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c
index 8045e4ff270c..0eff4a0c6a6c 100644
--- a/fs/ext4/inline.c
+++ b/fs/ext4/inline.c
@@ -934,6 +934,7 @@ static int ext4_da_convert_inline_data_to_extent(struct address_space *mapping,
 }
 
 #ifdef INLINE_DIR_DEBUG
+#include <linux/trace_printk.h>
 void ext4_show_inline_dir(struct inode *dir, struct buffer_head *bh,
 			  void *inline_start, int inline_size)
 {
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 02bc5027523a..b5336a81e619 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -8,6 +8,8 @@
 #define _LINUX_FTRACE_H
 
 #include <linux/trace_recursion.h>
+#include <linux/trace_controls.h>
+#include <linux/trace_printk.h>
 #include <linux/trace_clock.h>
 #include <linux/jump_label.h>
 #include <linux/kallsyms.h>
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index e5570a16cbb1..e87a40fbd152 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -31,7 +31,6 @@
 #include <linux/build_bug.h>
 #include <linux/sprintf.h>
 #include <linux/static_call_types.h>
-#include <linux/trace_printk.h>
 #include <linux/util_macros.h>
 #include <linux/wordpart.h>
 
diff --git a/include/linux/sunrpc/debug.h b/include/linux/sunrpc/debug.h
index ab61bed2f7af..7524f5d82fba 100644
--- a/include/linux/sunrpc/debug.h
+++ b/include/linux/sunrpc/debug.h
@@ -29,6 +29,7 @@ extern unsigned int		nlm_debug;
 # define ifdebug(fac)		if (unlikely(rpc_debug & RPCDBG_##fac))
 
 # if IS_ENABLED(CONFIG_SUNRPC_DEBUG_TRACE)
+#  include <linux/trace_printk.h>
 #  define __sunrpc_printk(fmt, ...)	trace_printk(fmt, ##__VA_ARGS__)
 # else
 #  define __sunrpc_printk(fmt, ...)	printk(KERN_DEFAULT fmt, ##__VA_ARGS__)
diff --git a/include/linux/trace_printk.h b/include/linux/trace_printk.h
index a488ea9e9f85..74ce4f8995c4 100644
--- a/include/linux/trace_printk.h
+++ b/include/linux/trace_printk.h
@@ -1,11 +1,12 @@
 /* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _LINUX_TRACE_PRINTK_H
 #define _LINUX_TRACE_PRINTK_H
+#if !defined(__ASSEMBLY__) && !defined(__GENKSYMS__) && !defined(BUILD_VDSO)
 
-#include <linux/compiler_attributes.h>
 #include <linux/instruction_pointer.h>
 #include <linux/stddef.h>
 #include <linux/stringify.h>
+#include <linux/stdarg.h>
 
 #ifdef CONFIG_TRACING
 static inline __printf(1, 2)
@@ -147,5 +148,5 @@ ftrace_vprintk(const char *fmt, va_list ap)
 	return 0;
 }
 #endif /* CONFIG_TRACING */
-
+#endif /* !defined(__ASSEMBLY__) && !defined(__GENKSYMS__) && !defined(BUILD_VDSO) */
 #endif
diff --git a/kernel/trace/ring_buffer_benchmark.c b/kernel/trace/ring_buffer_benchmark.c
index 593e3b59e42e..2bb25caebb75 100644
--- a/kernel/trace/ring_buffer_benchmark.c
+++ b/kernel/trace/ring_buffer_benchmark.c
@@ -5,6 +5,7 @@
  * Copyright (C) 2009 Steven Rostedt <srostedt@redhat.com>
  */
 #include <linux/ring_buffer.h>
+#include <linux/trace_printk.h>
 #include <linux/completion.h>
 #include <linux/kthread.h>
 #include <uapi/linux/sched/types.h>
diff --git a/samples/fprobe/fprobe_example.c b/samples/fprobe/fprobe_example.c
index bfe98ce826f3..de81b9b4ca7d 100644
--- a/samples/fprobe/fprobe_example.c
+++ b/samples/fprobe/fprobe_example.c
@@ -12,6 +12,7 @@
 
 #define pr_fmt(fmt) "%s: " fmt, __func__
 
+#include <linux/trace_printk.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/fprobe.h>
diff --git a/samples/ftrace/ftrace-direct-too.c b/samples/ftrace/ftrace-direct-too.c
index bf2411aa6fd7..159190f4103f 100644
--- a/samples/ftrace/ftrace-direct-too.c
+++ b/samples/ftrace/ftrace-direct-too.c
@@ -1,6 +1,5 @@
 // SPDX-License-Identifier: GPL-2.0-only
 #include <linux/module.h>
-
 #include <linux/mm.h> /* for handle_mm_fault() */
 #include <linux/ftrace.h>
 #if !defined(CONFIG_ARM64) && !defined(CONFIG_PPC32)
diff --git a/samples/trace_printk/trace-printk.c b/samples/trace_printk/trace-printk.c
index cfc159580263..ff37aeb8523e 100644
--- a/samples/trace_printk/trace-printk.c
+++ b/samples/trace_printk/trace-printk.c
@@ -1,4 +1,5 @@
 // SPDX-License-Identifier: GPL-2.0-only
+#include <linux/trace_printk.h>
 #include <linux/module.h>
 #include <linux/kthread.h>
 #include <linux/irq_work.h>
-- 
2.53.0

Re: [PATCH v2 2/2] tracing: Remove trace_printk.h from kernel.h

[Yury Norov]

On Mon, Jun 22, 2026 at 09:07:41AM -0400, Steven Rostedt wrote:
> From: Steven Rostedt <rostedt@goodmis.org>
> 
> There have been complaints about trace_printk.h causing more build time
> for being in kernel.h. Move it out of kernel.h and place it in the headers
> and C files that use it.
> 
> Link: https://lore.kernel.org/all/CAHk-=wikCBeVFjVXiY4o-oepdbjAoir5+TcAgtL12c4u1TpZLQ@mail.gmail.com/

Link is nice, but can you explain in the commit message what those
complaints exactly are? There's enough opinions shared to make a nice
summary. I even think it's important enough to become a Documentation
rule.
 
> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
> ---
> Changes since v1: https://patch.msgid.link/20260621093811.168514984@kernel.org
> 
> - Just remove trace_printk.h and fix up all the places that need it.
> 
>  arch/powerpc/kvm/book3s_xics.c         | 1 +
>  drivers/gpu/drm/i915/gt/intel_gtt.h    | 1 +
>  drivers/gpu/drm/i915/i915_gem.h        | 1 +
>  drivers/hwtracing/stm/dummy_stm.c      | 4 ++++
>  drivers/infiniband/hw/hfi1/trace_dbg.h | 1 +
>  drivers/usb/early/xhci-dbc.c           | 1 +
>  fs/ext4/inline.c                       | 1 +
>  include/linux/ftrace.h                 | 2 ++
>  include/linux/kernel.h                 | 1 -
>  include/linux/sunrpc/debug.h           | 1 +
>  include/linux/trace_printk.h           | 5 +++--
>  kernel/trace/ring_buffer_benchmark.c   | 1 +
>  samples/fprobe/fprobe_example.c        | 1 +
>  samples/ftrace/ftrace-direct-too.c     | 1 -
>  samples/trace_printk/trace-printk.c    | 1 +
>  15 files changed, 19 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/powerpc/kvm/book3s_xics.c b/arch/powerpc/kvm/book3s_xics.c
> index 74a44fa702b0..ef5eb596a56e 100644
> --- a/arch/powerpc/kvm/book3s_xics.c
> +++ b/arch/powerpc/kvm/book3s_xics.c
> @@ -26,6 +26,7 @@
>  #if 1
>  #define XICS_DBG(fmt...) do { } while (0)
>  #else
> +#include <linux/trace_printk.h>
>  #define XICS_DBG(fmt...) trace_printk(fmt)
>  #endif
>  
> diff --git a/drivers/gpu/drm/i915/gt/intel_gtt.h b/drivers/gpu/drm/i915/gt/intel_gtt.h
> index b54ee4f25af1..f6f223090760 100644
> --- a/drivers/gpu/drm/i915/gt/intel_gtt.h
> +++ b/drivers/gpu/drm/i915/gt/intel_gtt.h
> @@ -35,6 +35,7 @@
>  #define I915_GFP_ALLOW_FAIL (GFP_KERNEL | __GFP_RETRY_MAYFAIL | __GFP_NOWARN)
>  
>  #if IS_ENABLED(CONFIG_DRM_I915_TRACE_GTT)
> +#include <linux/trace_printk.h>

So, before it was included unconditionally, now it's included. It
looks technically correct, but conceptually - I'm not sure.

I'm not a developer of this driver, but ... here we need trace_printk.h
if TRACE_GTT is enabled, in the next header TRACE_GEM needs it. To me
it sounds like the whole driver simply needs trace_printk.h.

>  #define GTT_TRACE(...) trace_printk(__VA_ARGS__)
>  #else
>  #define GTT_TRACE(...)
> diff --git a/drivers/gpu/drm/i915/i915_gem.h b/drivers/gpu/drm/i915/i915_gem.h
> index 1da8fb61c09e..f490052e8964 100644
> --- a/drivers/gpu/drm/i915/i915_gem.h
> +++ b/drivers/gpu/drm/i915/i915_gem.h
> @@ -117,6 +117,7 @@ int i915_gem_open(struct drm_i915_private *i915, struct drm_file *file);
>  
>  #if IS_ENABLED(CONFIG_DRM_I915_TRACE_GEM)
>  #include <linux/trace_controls.h>
> +#include <linux/trace_printk.h>
>  #define GEM_TRACE(...) trace_printk(__VA_ARGS__)
>  #define GEM_TRACE_ERR(...) do {						\
>  	pr_err(__VA_ARGS__);						\
> diff --git a/drivers/hwtracing/stm/dummy_stm.c b/drivers/hwtracing/stm/dummy_stm.c
> index 38528ffdc0b3..784f9af7ccba 100644
> --- a/drivers/hwtracing/stm/dummy_stm.c
> +++ b/drivers/hwtracing/stm/dummy_stm.c
> @@ -14,6 +14,10 @@
>  #include <linux/stm.h>
>  #include <uapi/linux/stm.h>
>  
> +#ifdef DEBUG
> +#include <linux/trace_printk.h>
> +#endif
> +

Same here. The cost of adding the header in a particular C file is
unmeasurable. But playing "#undef DEBUG #ifdef DEBUG" games looks
weird.

Imagine, the developer has this DEBUG enabled, then adds another
debugging trace_pritnk() out of the DEBUG block, compiles his patch
well, then sends to the user, who has DEBUG disabled; and now we hit
the same problem as in the config-based case.

Let's put it simple: dummy_stm just needs trace_printk.h.

>  static ssize_t notrace
>  dummy_stm_packet(struct stm_data *stm_data, unsigned int master,
>  		 unsigned int channel, unsigned int packet, unsigned int flags,
> diff --git a/drivers/infiniband/hw/hfi1/trace_dbg.h b/drivers/infiniband/hw/hfi1/trace_dbg.h
> index 58304b91380f..30df5e246586 100644
> --- a/drivers/infiniband/hw/hfi1/trace_dbg.h
> +++ b/drivers/infiniband/hw/hfi1/trace_dbg.h
> @@ -103,6 +103,7 @@ __hfi1_trace_def(IOCTL);
>   */
>  
>  #ifdef HFI1_EARLY_DBG
> +#include <linux/trace_printk.h>
>  #define hfi1_dbg_early(fmt, ...) \
>  	trace_printk(fmt, ##__VA_ARGS__)
>  #else
> diff --git a/drivers/usb/early/xhci-dbc.c b/drivers/usb/early/xhci-dbc.c
> index 41118bba9197..955c73bd601f 100644
> --- a/drivers/usb/early/xhci-dbc.c
> +++ b/drivers/usb/early/xhci-dbc.c
> @@ -30,6 +30,7 @@ static struct xdbc_state xdbc;
>  static bool early_console_keep;
>  
>  #ifdef XDBC_TRACE
> +#include <linux/trace_printk.h>
>  #define	xdbc_trace	trace_printk
>  #else
>  static inline void xdbc_trace(const char *fmt, ...) { }
> diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c
> index 8045e4ff270c..0eff4a0c6a6c 100644
> --- a/fs/ext4/inline.c
> +++ b/fs/ext4/inline.c
> @@ -934,6 +934,7 @@ static int ext4_da_convert_inline_data_to_extent(struct address_space *mapping,
>  }
>  
>  #ifdef INLINE_DIR_DEBUG
> +#include <linux/trace_printk.h>
>  void ext4_show_inline_dir(struct inode *dir, struct buffer_head *bh,
>  			  void *inline_start, int inline_size)
>  {
> diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
> index 02bc5027523a..b5336a81e619 100644
> --- a/include/linux/ftrace.h
> +++ b/include/linux/ftrace.h
> @@ -8,6 +8,8 @@
>  #define _LINUX_FTRACE_H
>  
>  #include <linux/trace_recursion.h>
> +#include <linux/trace_controls.h>
> +#include <linux/trace_printk.h>
>  #include <linux/trace_clock.h>
>  #include <linux/jump_label.h>
>  #include <linux/kallsyms.h>
> diff --git a/include/linux/kernel.h b/include/linux/kernel.h
> index e5570a16cbb1..e87a40fbd152 100644
> --- a/include/linux/kernel.h
> +++ b/include/linux/kernel.h
> @@ -31,7 +31,6 @@
>  #include <linux/build_bug.h>
>  #include <linux/sprintf.h>
>  #include <linux/static_call_types.h>
> -#include <linux/trace_printk.h>
>  #include <linux/util_macros.h>
>  #include <linux/wordpart.h>
>  
> diff --git a/include/linux/sunrpc/debug.h b/include/linux/sunrpc/debug.h
> index ab61bed2f7af..7524f5d82fba 100644
> --- a/include/linux/sunrpc/debug.h
> +++ b/include/linux/sunrpc/debug.h
> @@ -29,6 +29,7 @@ extern unsigned int		nlm_debug;
>  # define ifdebug(fac)		if (unlikely(rpc_debug & RPCDBG_##fac))
>  
>  # if IS_ENABLED(CONFIG_SUNRPC_DEBUG_TRACE)
> +#  include <linux/trace_printk.h>
>  #  define __sunrpc_printk(fmt, ...)	trace_printk(fmt, ##__VA_ARGS__)
>  # else
>  #  define __sunrpc_printk(fmt, ...)	printk(KERN_DEFAULT fmt, ##__VA_ARGS__)
> diff --git a/include/linux/trace_printk.h b/include/linux/trace_printk.h
> index a488ea9e9f85..74ce4f8995c4 100644
> --- a/include/linux/trace_printk.h
> +++ b/include/linux/trace_printk.h
> @@ -1,11 +1,12 @@
>  /* SPDX-License-Identifier: GPL-2.0 */
>  #ifndef _LINUX_TRACE_PRINTK_H
>  #define _LINUX_TRACE_PRINTK_H
> +#if !defined(__ASSEMBLY__) && !defined(__GENKSYMS__) && !defined(BUILD_VDSO)
>  
> -#include <linux/compiler_attributes.h>
>  #include <linux/instruction_pointer.h>
>  #include <linux/stddef.h>
>  #include <linux/stringify.h>
> +#include <linux/stdarg.h>
>  
>  #ifdef CONFIG_TRACING
>  static inline __printf(1, 2)
> @@ -147,5 +148,5 @@ ftrace_vprintk(const char *fmt, va_list ap)
>  	return 0;
>  }
>  #endif /* CONFIG_TRACING */
> -
> +#endif /* !defined(__ASSEMBLY__) && !defined(__GENKSYMS__) && !defined(BUILD_VDSO) */
>  #endif
> diff --git a/kernel/trace/ring_buffer_benchmark.c b/kernel/trace/ring_buffer_benchmark.c
> index 593e3b59e42e..2bb25caebb75 100644
> --- a/kernel/trace/ring_buffer_benchmark.c
> +++ b/kernel/trace/ring_buffer_benchmark.c
> @@ -5,6 +5,7 @@
>   * Copyright (C) 2009 Steven Rostedt <srostedt@redhat.com>
>   */
>  #include <linux/ring_buffer.h>
> +#include <linux/trace_printk.h>
>  #include <linux/completion.h>
>  #include <linux/kthread.h>
>  #include <uapi/linux/sched/types.h>
> diff --git a/samples/fprobe/fprobe_example.c b/samples/fprobe/fprobe_example.c
> index bfe98ce826f3..de81b9b4ca7d 100644
> --- a/samples/fprobe/fprobe_example.c
> +++ b/samples/fprobe/fprobe_example.c
> @@ -12,6 +12,7 @@
>  
>  #define pr_fmt(fmt) "%s: " fmt, __func__
>  
> +#include <linux/trace_printk.h>
>  #include <linux/kernel.h>
>  #include <linux/module.h>
>  #include <linux/fprobe.h>
> diff --git a/samples/ftrace/ftrace-direct-too.c b/samples/ftrace/ftrace-direct-too.c
> index bf2411aa6fd7..159190f4103f 100644
> --- a/samples/ftrace/ftrace-direct-too.c
> +++ b/samples/ftrace/ftrace-direct-too.c
> @@ -1,6 +1,5 @@
>  // SPDX-License-Identifier: GPL-2.0-only
>  #include <linux/module.h>
> -
>  #include <linux/mm.h> /* for handle_mm_fault() */
>  #include <linux/ftrace.h>
>  #if !defined(CONFIG_ARM64) && !defined(CONFIG_PPC32)
> diff --git a/samples/trace_printk/trace-printk.c b/samples/trace_printk/trace-printk.c
> index cfc159580263..ff37aeb8523e 100644
> --- a/samples/trace_printk/trace-printk.c
> +++ b/samples/trace_printk/trace-printk.c
> @@ -1,4 +1,5 @@
>  // SPDX-License-Identifier: GPL-2.0-only
> +#include <linux/trace_printk.h>
>  #include <linux/module.h>
>  #include <linux/kthread.h>
>  #include <linux/irq_work.h>
> -- 
> 2.53.0
> 

Re: [PATCH v2 0/2] tracing: Remove trace_printk.h from kernel.h

[Masami Hiramatsu]

On Mon, 22 Jun 2026 09:07:39 -0400
Steven Rostedt <rostedt@kernel.org> wrote:

> 
> Remove trace_printk.h by creating a trace_controls.h for those places that
> need access to tracing prototypes like tracing_off() and for the places that
> need trace_printk() directly, to have it included directly.
> 
> Changse since v1: https://lore.kernel.org/all/20260621093430.264983361@kernel.org/
> 
> - Create a trace_controls.h header to move the prototypes into and not
>   include it back into kernel.h
> 
> - Just remove trace_printk.h from kernel.h with no alternative to keep the
>   previous behavior.
> 
> Steven Rostedt (2):
>       tracing: Move non-trace_printk prototypes into trace_controls.h
>       tracing: Remove trace_printk.h from kernel.h
> 

The series looks good to me.

Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>

for this series.

Thanks,

> ----
>  arch/powerpc/kvm/book3s_xics.c         |  1 +
>  arch/powerpc/xmon/xmon.c               |  1 +
>  arch/s390/kernel/ipl.c                 |  1 +
>  arch/s390/kernel/machine_kexec.c       |  1 +
>  drivers/gpu/drm/i915/gt/intel_gtt.h    |  1 +
>  drivers/gpu/drm/i915/i915_gem.h        |  2 ++
>  drivers/hwtracing/stm/dummy_stm.c      |  4 +++
>  drivers/infiniband/hw/hfi1/trace_dbg.h |  1 +
>  drivers/tty/sysrq.c                    |  1 +
>  drivers/usb/early/xhci-dbc.c           |  1 +
>  fs/ext4/inline.c                       |  1 +
>  include/linux/ftrace.h                 |  2 ++
>  include/linux/kernel.h                 |  1 -
>  include/linux/sunrpc/debug.h           |  1 +
>  include/linux/trace_controls.h         | 54 ++++++++++++++++++++++++++++++++
>  include/linux/trace_printk.h           | 56 ++--------------------------------
>  kernel/debug/debug_core.c              |  1 +
>  kernel/panic.c                         |  1 +
>  kernel/rcu/rcu.h                       |  2 ++
>  kernel/rcu/rcutorture.c                |  1 +
>  kernel/trace/ring_buffer_benchmark.c   |  1 +
>  kernel/trace/trace.h                   |  1 +
>  kernel/trace/trace_benchmark.c         |  1 +
>  lib/sys_info.c                         |  1 +
>  samples/fprobe/fprobe_example.c        |  1 +
>  samples/ftrace/ftrace-direct-too.c     |  1 -
>  samples/trace_printk/trace-printk.c    |  1 +
>  27 files changed, 86 insertions(+), 55 deletions(-)
>  create mode 100644 include/linux/trace_controls.h


-- 
Masami Hiramatsu (Google) <mhiramat@kernel.org>

Re: [PATCH v2 0/2] tracing: Remove trace_printk.h from kernel.h

[Steven Rostedt]

On Mon, 22 Jun 2026 23:44:16 +0900
Masami Hiramatsu (Google) <mhiramat@kernel.org> wrote:

> The series looks good to me.
> 
> Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>

Thanks!

-- Steve