* [for-next][PATCH 2/4] tracepoint: Have tracepoints created with DECLARE_TRACE() have _tp suffix
2025-05-15 8:51 [for-next][PATCH 0/4] tracing: Updates for v6.16 Steven Rostedt
2025-05-15 8:51 ` [for-next][PATCH 1/4] tracing: Cleanup upper_empty() in pid_list Steven Rostedt
@ 2025-05-15 8:51 ` Steven Rostedt
2025-05-15 8:51 ` [for-next][PATCH 3/4] tracing/sched: Use __string() instead of fixed lengths for task->comm Steven Rostedt
2025-05-15 8:51 ` [for-next][PATCH 4/4] tracing: Record trace_clock and recover when reboot Steven Rostedt
3 siblings, 0 replies; 5+ messages in thread
From: Steven Rostedt @ 2025-05-15 8:51 UTC (permalink / raw)
To: linux-kernel
Cc: Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Andrew Morton,
netdev, Jiri Olsa, Peter Zijlstra, David Ahern, Juri Lelli,
Breno Leitao, Alexei Starovoitov, Andrii Nakryiko,
Gabriele Monaco, Andrii Nakryiko
From: Steven Rostedt <rostedt@goodmis.org>
Most tracepoints in the kernel are created with TRACE_EVENT(). The
TRACE_EVENT() macro (and DECLARE_EVENT_CLASS() and DEFINE_EVENT() where in
reality, TRACE_EVENT() is just a helper macro that calls those other two
macros), will create not only a tracepoint (the function trace_<event>()
used in the kernel), it also exposes the tracepoint to user space along
with defining what fields will be saved by that tracepoint.
There are a few places that tracepoints are created in the kernel that are
not exposed to userspace via tracefs. They can only be accessed from code
within the kernel. These tracepoints are created with DEFINE_TRACE()
Most of these tracepoints end with "_tp". This is useful as when the
developer sees that, they know that the tracepoint is for in-kernel only
(meaning it can only be accessed inside the kernel, either directly by the
kernel or indirectly via modules and BPF programs) and is not exposed to
user space.
Instead of making this only a process to add "_tp", enforce it by making
the DECLARE_TRACE() append the "_tp" suffix to the tracepoint. This
requires adding DECLARE_TRACE_EVENT() macros for the TRACE_EVENT() macro
to use that keeps the original name.
Link: https://lore.kernel.org/all/20250418083351.20a60e64@gandalf.local.home/
Cc: netdev <netdev@vger.kernel.org>
Cc: Jiri Olsa <olsajiri@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: David Ahern <dsahern@kernel.org>
Cc: Juri Lelli <juri.lelli@gmail.com>
Cc: Breno Leitao <leitao@debian.org>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Gabriele Monaco <gmonaco@redhat.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Link: https://lore.kernel.org/20250510163730.092fad5b@gandalf.local.home
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
Documentation/trace/tracepoints.rst | 17 ++++++---
include/linux/tracepoint.h | 38 +++++++++++++------
include/trace/bpf_probe.h | 8 ++--
include/trace/define_trace.h | 17 ++++++++-
include/trace/events/sched.h | 30 +++++++--------
include/trace/events/tcp.h | 2 +-
.../testing/selftests/bpf/progs/raw_tp_null.c | 2 +-
.../selftests/bpf/progs/raw_tp_null_fail.c | 2 +-
.../selftests/bpf/progs/test_module_attach.c | 4 +-
.../bpf/progs/test_tp_btf_nullable.c | 4 +-
.../selftests/bpf/test_kmods/bpf_testmod.c | 8 ++--
11 files changed, 83 insertions(+), 49 deletions(-)
diff --git a/Documentation/trace/tracepoints.rst b/Documentation/trace/tracepoints.rst
index decabcc77b56..b35c40e3abbe 100644
--- a/Documentation/trace/tracepoints.rst
+++ b/Documentation/trace/tracepoints.rst
@@ -71,7 +71,7 @@ In subsys/file.c (where the tracing statement must be added)::
void somefct(void)
{
...
- trace_subsys_eventname(arg, task);
+ trace_subsys_eventname_tp(arg, task);
...
}
@@ -129,12 +129,12 @@ within an if statement with the following::
for (i = 0; i < count; i++)
tot += calculate_nuggets();
- trace_foo_bar(tot);
+ trace_foo_bar_tp(tot);
}
-All trace_<tracepoint>() calls have a matching trace_<tracepoint>_enabled()
+All trace_<tracepoint>_tp() calls have a matching trace_<tracepoint>_enabled()
function defined that returns true if the tracepoint is enabled and
-false otherwise. The trace_<tracepoint>() should always be within the
+false otherwise. The trace_<tracepoint>_tp() should always be within the
block of the if (trace_<tracepoint>_enabled()) to prevent races between
the tracepoint being enabled and the check being seen.
@@ -143,7 +143,10 @@ the static_key of the tracepoint to allow the if statement to be implemented
with jump labels and avoid conditional branches.
.. note:: The convenience macro TRACE_EVENT provides an alternative way to
- define tracepoints. Check http://lwn.net/Articles/379903,
+ define tracepoints. Note, DECLARE_TRACE(foo) creates a function
+ "trace_foo_tp()" whereas TRACE_EVENT(foo) creates a function
+ "trace_foo()", and also exposes the tracepoint as a trace event in
+ /sys/kernel/tracing/events directory. Check http://lwn.net/Articles/379903,
http://lwn.net/Articles/381064 and http://lwn.net/Articles/383362
for a series of articles with more details.
@@ -159,7 +162,9 @@ In a C file::
void do_trace_foo_bar_wrapper(args)
{
- trace_foo_bar(args);
+ trace_foo_bar_tp(args); // for tracepoints created via DECLARE_TRACE
+ // or
+ trace_foo_bar(args); // for tracepoints created via TRACE_EVENT
}
In the header file::
diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
index a351763e6965..826ce3f8e1f8 100644
--- a/include/linux/tracepoint.h
+++ b/include/linux/tracepoint.h
@@ -464,16 +464,30 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p)
#endif
#define DECLARE_TRACE(name, proto, args) \
- __DECLARE_TRACE(name, PARAMS(proto), PARAMS(args), \
+ __DECLARE_TRACE(name##_tp, PARAMS(proto), PARAMS(args), \
cpu_online(raw_smp_processor_id()), \
PARAMS(void *__data, proto))
#define DECLARE_TRACE_CONDITION(name, proto, args, cond) \
- __DECLARE_TRACE(name, PARAMS(proto), PARAMS(args), \
+ __DECLARE_TRACE(name##_tp, PARAMS(proto), PARAMS(args), \
cpu_online(raw_smp_processor_id()) && (PARAMS(cond)), \
PARAMS(void *__data, proto))
#define DECLARE_TRACE_SYSCALL(name, proto, args) \
+ __DECLARE_TRACE_SYSCALL(name##_tp, PARAMS(proto), PARAMS(args), \
+ PARAMS(void *__data, proto))
+
+#define DECLARE_TRACE_EVENT(name, proto, args) \
+ __DECLARE_TRACE(name, PARAMS(proto), PARAMS(args), \
+ cpu_online(raw_smp_processor_id()), \
+ PARAMS(void *__data, proto))
+
+#define DECLARE_TRACE_EVENT_CONDITION(name, proto, args, cond) \
+ __DECLARE_TRACE(name, PARAMS(proto), PARAMS(args), \
+ cpu_online(raw_smp_processor_id()) && (PARAMS(cond)), \
+ PARAMS(void *__data, proto))
+
+#define DECLARE_TRACE_EVENT_SYSCALL(name, proto, args) \
__DECLARE_TRACE_SYSCALL(name, PARAMS(proto), PARAMS(args), \
PARAMS(void *__data, proto))
@@ -591,32 +605,32 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p)
#define DECLARE_EVENT_CLASS(name, proto, args, tstruct, assign, print)
#define DEFINE_EVENT(template, name, proto, args) \
- DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
+ DECLARE_TRACE_EVENT(name, PARAMS(proto), PARAMS(args))
#define DEFINE_EVENT_FN(template, name, proto, args, reg, unreg)\
- DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
+ DECLARE_TRACE_EVENT(name, PARAMS(proto), PARAMS(args))
#define DEFINE_EVENT_PRINT(template, name, proto, args, print) \
- DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
+ DECLARE_TRACE_EVENT(name, PARAMS(proto), PARAMS(args))
#define DEFINE_EVENT_CONDITION(template, name, proto, \
args, cond) \
- DECLARE_TRACE_CONDITION(name, PARAMS(proto), \
+ DECLARE_TRACE_EVENT_CONDITION(name, PARAMS(proto), \
PARAMS(args), PARAMS(cond))
#define TRACE_EVENT(name, proto, args, struct, assign, print) \
- DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
+ DECLARE_TRACE_EVENT(name, PARAMS(proto), PARAMS(args))
#define TRACE_EVENT_FN(name, proto, args, struct, \
assign, print, reg, unreg) \
- DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
-#define TRACE_EVENT_FN_COND(name, proto, args, cond, struct, \
+ DECLARE_TRACE_EVENT(name, PARAMS(proto), PARAMS(args))
+#define TRACE_EVENT_FN_COND(name, proto, args, cond, struct, \
assign, print, reg, unreg) \
- DECLARE_TRACE_CONDITION(name, PARAMS(proto), \
+ DECLARE_TRACE_EVENT_CONDITION(name, PARAMS(proto), \
PARAMS(args), PARAMS(cond))
#define TRACE_EVENT_CONDITION(name, proto, args, cond, \
struct, assign, print) \
- DECLARE_TRACE_CONDITION(name, PARAMS(proto), \
+ DECLARE_TRACE_EVENT_CONDITION(name, PARAMS(proto), \
PARAMS(args), PARAMS(cond))
#define TRACE_EVENT_SYSCALL(name, proto, args, struct, assign, \
print, reg, unreg) \
- DECLARE_TRACE_SYSCALL(name, PARAMS(proto), PARAMS(args))
+ DECLARE_TRACE_EVENT_SYSCALL(name, PARAMS(proto), PARAMS(args))
#define TRACE_EVENT_FLAGS(event, flag)
diff --git a/include/trace/bpf_probe.h b/include/trace/bpf_probe.h
index 183fa2aa2935..9391d54d3f12 100644
--- a/include/trace/bpf_probe.h
+++ b/include/trace/bpf_probe.h
@@ -119,14 +119,14 @@ static inline void bpf_test_buffer_##call(void) \
#undef DECLARE_TRACE
#define DECLARE_TRACE(call, proto, args) \
- __BPF_DECLARE_TRACE(call, PARAMS(proto), PARAMS(args)) \
- __DEFINE_EVENT(call, call, PARAMS(proto), PARAMS(args), 0)
+ __BPF_DECLARE_TRACE(call##_tp, PARAMS(proto), PARAMS(args)) \
+ __DEFINE_EVENT(call##_tp, call##_tp, PARAMS(proto), PARAMS(args), 0)
#undef DECLARE_TRACE_WRITABLE
#define DECLARE_TRACE_WRITABLE(call, proto, args, size) \
__CHECK_WRITABLE_BUF_SIZE(call, PARAMS(proto), PARAMS(args), size) \
- __BPF_DECLARE_TRACE(call, PARAMS(proto), PARAMS(args)) \
- __DEFINE_EVENT(call, call, PARAMS(proto), PARAMS(args), size)
+ __BPF_DECLARE_TRACE(call##_tp, PARAMS(proto), PARAMS(args)) \
+ __DEFINE_EVENT(call##_tp, call##_tp, PARAMS(proto), PARAMS(args), size)
#include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
diff --git a/include/trace/define_trace.h b/include/trace/define_trace.h
index ed52d0506c69..b2ba5a80583f 100644
--- a/include/trace/define_trace.h
+++ b/include/trace/define_trace.h
@@ -74,10 +74,18 @@
#undef DECLARE_TRACE
#define DECLARE_TRACE(name, proto, args) \
- DEFINE_TRACE(name, PARAMS(proto), PARAMS(args))
+ DEFINE_TRACE(name##_tp, PARAMS(proto), PARAMS(args))
#undef DECLARE_TRACE_CONDITION
#define DECLARE_TRACE_CONDITION(name, proto, args, cond) \
+ DEFINE_TRACE(name##_tp, PARAMS(proto), PARAMS(args))
+
+#undef DECLARE_TRACE_EVENT
+#define DECLARE_TRACE_EVENT(name, proto, args) \
+ DEFINE_TRACE(name, PARAMS(proto), PARAMS(args))
+
+#undef DECLARE_TRACE_EVENT_CONDITION
+#define DECLARE_TRACE_EVENT_CONDITION(name, proto, args, cond) \
DEFINE_TRACE(name, PARAMS(proto), PARAMS(args))
/* If requested, create helpers for calling these tracepoints from Rust. */
@@ -115,6 +123,11 @@
#undef DECLARE_TRACE_CONDITION
#define DECLARE_TRACE_CONDITION(name, proto, args, cond)
+#undef DECLARE_TRACE_EVENT
+#define DECLARE_TRACE_EVENT(name, proto, args)
+#undef DECLARE_TRACE_EVENT_CONDITION
+#define DECLARE_TRACE_EVENT_CONDITION(name, proto, args, cond)
+
#ifdef TRACEPOINTS_ENABLED
#include <trace/trace_events.h>
#include <trace/perf.h>
@@ -136,6 +149,8 @@
#undef TRACE_HEADER_MULTI_READ
#undef DECLARE_TRACE
#undef DECLARE_TRACE_CONDITION
+#undef DECLARE_TRACE_EVENT
+#undef DECLARE_TRACE_EVENT_CONDITION
/* Only undef what we defined in this file */
#ifdef UNDEF_TRACE_INCLUDE_FILE
diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h
index 8994e97d86c1..152fc8b37aa5 100644
--- a/include/trace/events/sched.h
+++ b/include/trace/events/sched.h
@@ -773,64 +773,64 @@ TRACE_EVENT(sched_wake_idle_without_ipi,
*
* Postfixed with _tp to make them easily identifiable in the code.
*/
-DECLARE_TRACE(pelt_cfs_tp,
+DECLARE_TRACE(pelt_cfs,
TP_PROTO(struct cfs_rq *cfs_rq),
TP_ARGS(cfs_rq));
-DECLARE_TRACE(pelt_rt_tp,
+DECLARE_TRACE(pelt_rt,
TP_PROTO(struct rq *rq),
TP_ARGS(rq));
-DECLARE_TRACE(pelt_dl_tp,
+DECLARE_TRACE(pelt_dl,
TP_PROTO(struct rq *rq),
TP_ARGS(rq));
-DECLARE_TRACE(pelt_hw_tp,
+DECLARE_TRACE(pelt_hw,
TP_PROTO(struct rq *rq),
TP_ARGS(rq));
-DECLARE_TRACE(pelt_irq_tp,
+DECLARE_TRACE(pelt_irq,
TP_PROTO(struct rq *rq),
TP_ARGS(rq));
-DECLARE_TRACE(pelt_se_tp,
+DECLARE_TRACE(pelt_se,
TP_PROTO(struct sched_entity *se),
TP_ARGS(se));
-DECLARE_TRACE(sched_cpu_capacity_tp,
+DECLARE_TRACE(sched_cpu_capacity,
TP_PROTO(struct rq *rq),
TP_ARGS(rq));
-DECLARE_TRACE(sched_overutilized_tp,
+DECLARE_TRACE(sched_overutilized,
TP_PROTO(struct root_domain *rd, bool overutilized),
TP_ARGS(rd, overutilized));
-DECLARE_TRACE(sched_util_est_cfs_tp,
+DECLARE_TRACE(sched_util_est_cfs,
TP_PROTO(struct cfs_rq *cfs_rq),
TP_ARGS(cfs_rq));
-DECLARE_TRACE(sched_util_est_se_tp,
+DECLARE_TRACE(sched_util_est_se,
TP_PROTO(struct sched_entity *se),
TP_ARGS(se));
-DECLARE_TRACE(sched_update_nr_running_tp,
+DECLARE_TRACE(sched_update_nr_running,
TP_PROTO(struct rq *rq, int change),
TP_ARGS(rq, change));
-DECLARE_TRACE(sched_compute_energy_tp,
+DECLARE_TRACE(sched_compute_energy,
TP_PROTO(struct task_struct *p, int dst_cpu, unsigned long energy,
unsigned long max_util, unsigned long busy_time),
TP_ARGS(p, dst_cpu, energy, max_util, busy_time));
-DECLARE_TRACE(sched_entry_tp,
+DECLARE_TRACE(sched_entry,
TP_PROTO(bool preempt, unsigned long ip),
TP_ARGS(preempt, ip));
-DECLARE_TRACE(sched_exit_tp,
+DECLARE_TRACE(sched_exit,
TP_PROTO(bool is_switch, unsigned long ip),
TP_ARGS(is_switch, ip));
-DECLARE_TRACE_CONDITION(sched_set_state_tp,
+DECLARE_TRACE_CONDITION(sched_set_state,
TP_PROTO(struct task_struct *tsk, int state),
TP_ARGS(tsk, state),
TP_CONDITION(!!(tsk->__state) != !!state));
diff --git a/include/trace/events/tcp.h b/include/trace/events/tcp.h
index 1a40c41ff8c3..4f9fa1b5b89b 100644
--- a/include/trace/events/tcp.h
+++ b/include/trace/events/tcp.h
@@ -259,7 +259,7 @@ TRACE_EVENT(tcp_retransmit_synack,
__entry->saddr_v6, __entry->daddr_v6)
);
-DECLARE_TRACE(tcp_cwnd_reduction_tp,
+DECLARE_TRACE(tcp_cwnd_reduction,
TP_PROTO(const struct sock *sk, int newly_acked_sacked,
int newly_lost, int flag),
TP_ARGS(sk, newly_acked_sacked, newly_lost, flag)
diff --git a/tools/testing/selftests/bpf/progs/raw_tp_null.c b/tools/testing/selftests/bpf/progs/raw_tp_null.c
index 5927054b6dd9..efa416f53968 100644
--- a/tools/testing/selftests/bpf/progs/raw_tp_null.c
+++ b/tools/testing/selftests/bpf/progs/raw_tp_null.c
@@ -10,7 +10,7 @@ char _license[] SEC("license") = "GPL";
int tid;
int i;
-SEC("tp_btf/bpf_testmod_test_raw_tp_null")
+SEC("tp_btf/bpf_testmod_test_raw_tp_null_tp")
int BPF_PROG(test_raw_tp_null, struct sk_buff *skb)
{
struct task_struct *task = bpf_get_current_task_btf();
diff --git a/tools/testing/selftests/bpf/progs/raw_tp_null_fail.c b/tools/testing/selftests/bpf/progs/raw_tp_null_fail.c
index 38d669957bf1..0d58114a4955 100644
--- a/tools/testing/selftests/bpf/progs/raw_tp_null_fail.c
+++ b/tools/testing/selftests/bpf/progs/raw_tp_null_fail.c
@@ -8,7 +8,7 @@
char _license[] SEC("license") = "GPL";
/* Ensure module parameter has PTR_MAYBE_NULL */
-SEC("tp_btf/bpf_testmod_test_raw_tp_null")
+SEC("tp_btf/bpf_testmod_test_raw_tp_null_tp")
__failure __msg("R1 invalid mem access 'trusted_ptr_or_null_'")
int test_raw_tp_null_bpf_testmod_test_raw_tp_null_arg_1(void *ctx) {
asm volatile("r1 = *(u64 *)(r1 +0); r1 = *(u64 *)(r1 +0);" ::: __clobber_all);
diff --git a/tools/testing/selftests/bpf/progs/test_module_attach.c b/tools/testing/selftests/bpf/progs/test_module_attach.c
index 7f3c233943b3..03d7f89787a1 100644
--- a/tools/testing/selftests/bpf/progs/test_module_attach.c
+++ b/tools/testing/selftests/bpf/progs/test_module_attach.c
@@ -19,7 +19,7 @@ int BPF_PROG(handle_raw_tp,
__u32 raw_tp_bare_write_sz = 0;
-SEC("raw_tp/bpf_testmod_test_write_bare")
+SEC("raw_tp/bpf_testmod_test_write_bare_tp")
int BPF_PROG(handle_raw_tp_bare,
struct task_struct *task, struct bpf_testmod_test_write_ctx *write_ctx)
{
@@ -31,7 +31,7 @@ int raw_tp_writable_bare_in_val = 0;
int raw_tp_writable_bare_early_ret = 0;
int raw_tp_writable_bare_out_val = 0;
-SEC("raw_tp.w/bpf_testmod_test_writable_bare")
+SEC("raw_tp.w/bpf_testmod_test_writable_bare_tp")
int BPF_PROG(handle_raw_tp_writable_bare,
struct bpf_testmod_test_writable_ctx *writable)
{
diff --git a/tools/testing/selftests/bpf/progs/test_tp_btf_nullable.c b/tools/testing/selftests/bpf/progs/test_tp_btf_nullable.c
index 39ff06f2c834..cf0547a613ff 100644
--- a/tools/testing/selftests/bpf/progs/test_tp_btf_nullable.c
+++ b/tools/testing/selftests/bpf/progs/test_tp_btf_nullable.c
@@ -6,14 +6,14 @@
#include "../test_kmods/bpf_testmod.h"
#include "bpf_misc.h"
-SEC("tp_btf/bpf_testmod_test_nullable_bare")
+SEC("tp_btf/bpf_testmod_test_nullable_bare_tp")
__failure __msg("R1 invalid mem access 'trusted_ptr_or_null_'")
int BPF_PROG(handle_tp_btf_nullable_bare1, struct bpf_testmod_test_read_ctx *nullable_ctx)
{
return nullable_ctx->len;
}
-SEC("tp_btf/bpf_testmod_test_nullable_bare")
+SEC("tp_btf/bpf_testmod_test_nullable_bare_tp")
int BPF_PROG(handle_tp_btf_nullable_bare2, struct bpf_testmod_test_read_ctx *nullable_ctx)
{
if (nullable_ctx)
diff --git a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c
index 3220f1d28697..18eded4d1d15 100644
--- a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c
+++ b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c
@@ -413,7 +413,7 @@ bpf_testmod_test_read(struct file *file, struct kobject *kobj,
(void)bpf_testmod_test_arg_ptr_to_struct(&struct_arg1_2);
- (void)trace_bpf_testmod_test_raw_tp_null(NULL);
+ (void)trace_bpf_testmod_test_raw_tp_null_tp(NULL);
bpf_testmod_test_struct_ops3();
@@ -431,14 +431,14 @@ bpf_testmod_test_read(struct file *file, struct kobject *kobj,
if (bpf_testmod_loop_test(101) > 100)
trace_bpf_testmod_test_read(current, &ctx);
- trace_bpf_testmod_test_nullable_bare(NULL);
+ trace_bpf_testmod_test_nullable_bare_tp(NULL);
/* Magic number to enable writable tp */
if (len == 64) {
struct bpf_testmod_test_writable_ctx writable = {
.val = 1024,
};
- trace_bpf_testmod_test_writable_bare(&writable);
+ trace_bpf_testmod_test_writable_bare_tp(&writable);
if (writable.early_ret)
return snprintf(buf, len, "%d\n", writable.val);
}
@@ -470,7 +470,7 @@ bpf_testmod_test_write(struct file *file, struct kobject *kobj,
.len = len,
};
- trace_bpf_testmod_test_write_bare(current, &ctx);
+ trace_bpf_testmod_test_write_bare_tp(current, &ctx);
return -EIO; /* always fail */
}
--
2.47.2
^ permalink raw reply related [flat|nested] 5+ messages in thread* [for-next][PATCH 3/4] tracing/sched: Use __string() instead of fixed lengths for task->comm
2025-05-15 8:51 [for-next][PATCH 0/4] tracing: Updates for v6.16 Steven Rostedt
2025-05-15 8:51 ` [for-next][PATCH 1/4] tracing: Cleanup upper_empty() in pid_list Steven Rostedt
2025-05-15 8:51 ` [for-next][PATCH 2/4] tracepoint: Have tracepoints created with DECLARE_TRACE() have _tp suffix Steven Rostedt
@ 2025-05-15 8:51 ` Steven Rostedt
2025-05-15 8:51 ` [for-next][PATCH 4/4] tracing: Record trace_clock and recover when reboot Steven Rostedt
3 siblings, 0 replies; 5+ messages in thread
From: Steven Rostedt @ 2025-05-15 8:51 UTC (permalink / raw)
To: linux-kernel
Cc: Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Andrew Morton,
Bhupesh, Linus Torvalds, Peter Zijlstra,
Sebastian Andrzej Siewior, Thomas Gleixner, Juri Lelli
From: Steven Rostedt <rostedt@goodmis.org>
The sched_switch and sched_waking events hardcoded the length of the comm
it recorded because these events were created before the dynamic strings
were implemented. Unfortunately, several other events copied this method.
As the size of the comm may change in the future, make the string dynamic.
The dynamic string requires a 4 byte meta data to hold the size and offset
of the string. The amount stored in the ring buffer will then be the
strlen(comm) + 5 (for the \n), and aligned to 4 bytes if there's no other
strings. This means that a task comm can have up to 10 characters before it
requires another 4 bytes in the ring buffer. Most tasks are usually less
than that, so this should not be a problem, and it also allows the name to
be extended over the TASK_COMM_LEN [1]
Note, sched_switch and the sched_waking trace events still hardcode the
length, as there is tooling that still requires that. An effort to update
the tooling will be made to allow this to change in the future.
[1] https://lore.kernel.org/all/20250507110444.963779-1-bhupesh@igalia.com/
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Bhupesh <bhupesh@igalia.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Juri Lelli <juri.lelli@redhat.com>
Link: https://lore.kernel.org/20250507133458.51bafd95@gandalf.local.home
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
include/trace/events/sched.h | 94 ++++++++++++++++++------------------
1 file changed, 47 insertions(+), 47 deletions(-)
diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h
index 152fc8b37aa5..fadc7592372b 100644
--- a/include/trace/events/sched.h
+++ b/include/trace/events/sched.h
@@ -20,16 +20,16 @@ TRACE_EVENT(sched_kthread_stop,
TP_ARGS(t),
TP_STRUCT__entry(
- __array( char, comm, TASK_COMM_LEN )
- __field( pid_t, pid )
+ __string( comm, t->comm )
+ __field( pid_t, pid )
),
TP_fast_assign(
- memcpy(__entry->comm, t->comm, TASK_COMM_LEN);
+ __assign_str(comm);
__entry->pid = t->pid;
),
- TP_printk("comm=%s pid=%d", __entry->comm, __entry->pid)
+ TP_printk("comm=%s pid=%d", __get_str(comm), __entry->pid)
);
/*
@@ -276,15 +276,15 @@ TRACE_EVENT(sched_migrate_task,
TP_ARGS(p, dest_cpu),
TP_STRUCT__entry(
- __array( char, comm, TASK_COMM_LEN )
- __field( pid_t, pid )
- __field( int, prio )
- __field( int, orig_cpu )
- __field( int, dest_cpu )
+ __string( comm, p->comm )
+ __field( pid_t, pid )
+ __field( int, prio )
+ __field( int, orig_cpu )
+ __field( int, dest_cpu )
),
TP_fast_assign(
- memcpy(__entry->comm, p->comm, TASK_COMM_LEN);
+ __assign_str(comm);
__entry->pid = p->pid;
__entry->prio = p->prio; /* XXX SCHED_DEADLINE */
__entry->orig_cpu = task_cpu(p);
@@ -292,7 +292,7 @@ TRACE_EVENT(sched_migrate_task,
),
TP_printk("comm=%s pid=%d prio=%d orig_cpu=%d dest_cpu=%d",
- __entry->comm, __entry->pid, __entry->prio,
+ __get_str(comm), __entry->pid, __entry->prio,
__entry->orig_cpu, __entry->dest_cpu)
);
@@ -303,19 +303,19 @@ DECLARE_EVENT_CLASS(sched_process_template,
TP_ARGS(p),
TP_STRUCT__entry(
- __array( char, comm, TASK_COMM_LEN )
- __field( pid_t, pid )
- __field( int, prio )
+ __string( comm, p->comm )
+ __field( pid_t, pid )
+ __field( int, prio )
),
TP_fast_assign(
- memcpy(__entry->comm, p->comm, TASK_COMM_LEN);
+ __assign_str(comm);
__entry->pid = p->pid;
__entry->prio = p->prio; /* XXX SCHED_DEADLINE */
),
TP_printk("comm=%s pid=%d prio=%d",
- __entry->comm, __entry->pid, __entry->prio)
+ __get_str(comm), __entry->pid, __entry->prio)
);
/*
@@ -349,19 +349,19 @@ TRACE_EVENT(sched_process_wait,
TP_ARGS(pid),
TP_STRUCT__entry(
- __array( char, comm, TASK_COMM_LEN )
+ __string( comm, current->comm )
__field( pid_t, pid )
__field( int, prio )
),
TP_fast_assign(
- memcpy(__entry->comm, current->comm, TASK_COMM_LEN);
+ __assign_str(comm);
__entry->pid = pid_nr(pid);
__entry->prio = current->prio; /* XXX SCHED_DEADLINE */
),
TP_printk("comm=%s pid=%d prio=%d",
- __entry->comm, __entry->pid, __entry->prio)
+ __get_str(comm), __entry->pid, __entry->prio)
);
/*
@@ -374,22 +374,22 @@ TRACE_EVENT(sched_process_fork,
TP_ARGS(parent, child),
TP_STRUCT__entry(
- __array( char, parent_comm, TASK_COMM_LEN )
- __field( pid_t, parent_pid )
- __array( char, child_comm, TASK_COMM_LEN )
- __field( pid_t, child_pid )
+ __string( parent_comm, parent->comm )
+ __field( pid_t, parent_pid )
+ __string( child_comm, child->comm )
+ __field( pid_t, child_pid )
),
TP_fast_assign(
- memcpy(__entry->parent_comm, parent->comm, TASK_COMM_LEN);
+ __assign_str(parent_comm);
__entry->parent_pid = parent->pid;
- memcpy(__entry->child_comm, child->comm, TASK_COMM_LEN);
+ __assign_str(child_comm);
__entry->child_pid = child->pid;
),
TP_printk("comm=%s pid=%d child_comm=%s child_pid=%d",
- __entry->parent_comm, __entry->parent_pid,
- __entry->child_comm, __entry->child_pid)
+ __get_str(parent_comm), __entry->parent_pid,
+ __get_str(child_comm), __entry->child_pid)
);
/*
@@ -473,19 +473,19 @@ DECLARE_EVENT_CLASS_SCHEDSTAT(sched_stat_template,
TP_ARGS(__perf_task(tsk), __perf_count(delay)),
TP_STRUCT__entry(
- __array( char, comm, TASK_COMM_LEN )
- __field( pid_t, pid )
- __field( u64, delay )
+ __string( comm, tsk->comm )
+ __field( pid_t, pid )
+ __field( u64, delay )
),
TP_fast_assign(
- memcpy(__entry->comm, tsk->comm, TASK_COMM_LEN);
+ __assign_str(comm);
__entry->pid = tsk->pid;
__entry->delay = delay;
),
TP_printk("comm=%s pid=%d delay=%Lu [ns]",
- __entry->comm, __entry->pid,
+ __get_str(comm), __entry->pid,
(unsigned long long)__entry->delay)
);
@@ -531,19 +531,19 @@ DECLARE_EVENT_CLASS(sched_stat_runtime,
TP_ARGS(tsk, __perf_count(runtime)),
TP_STRUCT__entry(
- __array( char, comm, TASK_COMM_LEN )
- __field( pid_t, pid )
- __field( u64, runtime )
+ __string( comm, tsk->comm )
+ __field( pid_t, pid )
+ __field( u64, runtime )
),
TP_fast_assign(
- memcpy(__entry->comm, tsk->comm, TASK_COMM_LEN);
+ __assign_str(comm);
__entry->pid = tsk->pid;
__entry->runtime = runtime;
),
TP_printk("comm=%s pid=%d runtime=%Lu [ns]",
- __entry->comm, __entry->pid,
+ __get_str(comm), __entry->pid,
(unsigned long long)__entry->runtime)
);
@@ -562,14 +562,14 @@ TRACE_EVENT(sched_pi_setprio,
TP_ARGS(tsk, pi_task),
TP_STRUCT__entry(
- __array( char, comm, TASK_COMM_LEN )
- __field( pid_t, pid )
- __field( int, oldprio )
- __field( int, newprio )
+ __string( comm, tsk->comm )
+ __field( pid_t, pid )
+ __field( int, oldprio )
+ __field( int, newprio )
),
TP_fast_assign(
- memcpy(__entry->comm, tsk->comm, TASK_COMM_LEN);
+ __assign_str(comm);
__entry->pid = tsk->pid;
__entry->oldprio = tsk->prio;
__entry->newprio = pi_task ?
@@ -579,7 +579,7 @@ TRACE_EVENT(sched_pi_setprio,
),
TP_printk("comm=%s pid=%d oldprio=%d newprio=%d",
- __entry->comm, __entry->pid,
+ __get_str(comm), __entry->pid,
__entry->oldprio, __entry->newprio)
);
@@ -589,16 +589,16 @@ TRACE_EVENT(sched_process_hang,
TP_ARGS(tsk),
TP_STRUCT__entry(
- __array( char, comm, TASK_COMM_LEN )
- __field( pid_t, pid )
+ __string( comm, tsk->comm )
+ __field( pid_t, pid )
),
TP_fast_assign(
- memcpy(__entry->comm, tsk->comm, TASK_COMM_LEN);
+ __assign_str(comm);
__entry->pid = tsk->pid;
),
- TP_printk("comm=%s pid=%d", __entry->comm, __entry->pid)
+ TP_printk("comm=%s pid=%d", __get_str(comm), __entry->pid)
);
#endif /* CONFIG_DETECT_HUNG_TASK */
--
2.47.2
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