2024-06-10 21:27:04

by Masami Hiramatsu

Subject: [PATCH 2/3] tracing/kprobe: Remove unneeded WARN_ON_ONCE() in selftests

From: Masami Hiramatsu (Google) <[email protected]>

Since the kprobe-events selftest shows OK or NG with the reason, the
WARN_ON_ONCE()s for each place are redundant. Let's remove it.

Signed-off-by: Masami Hiramatsu (Google) <[email protected]>
---
kernel/trace/trace_kprobe.c | 26 +++++++++++++-------------
1 file changed, 13 insertions(+), 13 deletions(-)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 16383247bdbf..4abed36544d0 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -2023,18 +2023,18 @@ static __init int kprobe_trace_self_tests_init(void)
pr_info("Testing kprobe tracing: ");

ret = create_or_delete_trace_kprobe("p:testprobe kprobe_trace_selftest_target $stack $stack0 +0($stack)");
- if (WARN_ON_ONCE(ret)) {
+ if (ret) {
pr_warn("error on probing function entry.\n");
warn++;
} else {
/* Enable trace point */
tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
- if (WARN_ON_ONCE(tk == NULL)) {
+ if (tk == NULL) {
pr_warn("error on getting new probe.\n");
warn++;
} else {
file = find_trace_probe_file(tk, top_trace_array());
- if (WARN_ON_ONCE(file == NULL)) {
+ if (file == NULL) {
pr_warn("error on getting probe file.\n");
warn++;
} else
@@ -2044,18 +2044,18 @@ static __init int kprobe_trace_self_tests_init(void)
}

ret = create_or_delete_trace_kprobe("r:testprobe2 kprobe_trace_selftest_target $retval");
- if (WARN_ON_ONCE(ret)) {
+ if (ret) {
pr_warn("error on probing function return.\n");
warn++;
} else {
/* Enable trace point */
tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
- if (WARN_ON_ONCE(tk == NULL)) {
+ if (tk == NULL) {
pr_warn("error on getting 2nd new probe.\n");
warn++;
} else {
file = find_trace_probe_file(tk, top_trace_array());
- if (WARN_ON_ONCE(file == NULL)) {
+ if (file == NULL) {
pr_warn("error on getting probe file.\n");
warn++;
} else
@@ -2079,7 +2079,7 @@ static __init int kprobe_trace_self_tests_init(void)

/* Disable trace points before removing it */
tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
- if (WARN_ON_ONCE(tk == NULL)) {
+ if (tk == NULL) {
pr_warn("error on getting test probe.\n");
warn++;
} else {
@@ -2089,7 +2089,7 @@ static __init int kprobe_trace_self_tests_init(void)
}

file = find_trace_probe_file(tk, top_trace_array());
- if (WARN_ON_ONCE(file == NULL)) {
+ if (file == NULL) {
pr_warn("error on getting probe file.\n");
warn++;
} else
@@ -2098,7 +2098,7 @@ static __init int kprobe_trace_self_tests_init(void)
}

tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
- if (WARN_ON_ONCE(tk == NULL)) {
+ if (tk == NULL) {
pr_warn("error on getting 2nd test probe.\n");
warn++;
} else {
@@ -2108,7 +2108,7 @@ static __init int kprobe_trace_self_tests_init(void)
}

file = find_trace_probe_file(tk, top_trace_array());
- if (WARN_ON_ONCE(file == NULL)) {
+ if (file == NULL) {
pr_warn("error on getting probe file.\n");
warn++;
} else
@@ -2117,20 +2117,20 @@ static __init int kprobe_trace_self_tests_init(void)
}

ret = create_or_delete_trace_kprobe("-:testprobe");
- if (WARN_ON_ONCE(ret)) {
+ if (ret) {
pr_warn("error on deleting a probe.\n");
warn++;
}

ret = create_or_delete_trace_kprobe("-:testprobe2");
- if (WARN_ON_ONCE(ret)) {
+ if (ret) {
pr_warn("error on deleting a probe.\n");
warn++;
}

end:
ret = dyn_events_release_all(&trace_kprobe_ops);
- if (WARN_ON_ONCE(ret)) {
+ if (ret) {
pr_warn("error on cleaning up probes.\n");
warn++;
}

2024-06-10 21:40:49

by Steven Rostedt

Subject: Re: [PATCH 2/3] tracing/kprobe: Remove unneeded WARN_ON_ONCE() in selftests

On Tue, 11 Jun 2024 06:26:44 +0900
"Masami Hiramatsu (Google)" <[email protected]> wrote:

> From: Masami Hiramatsu (Google) <[email protected]>
>
> Since the kprobe-events selftest shows OK or NG with the reason, the
> WARN_ON_ONCE()s for each place are redundant. Let's remove it.

Note, the ktests we run to validate commits, fail when it detects a WARN()
triggered.

If this fails in any configuration, ktest will not detect it failed.

-- Steve


>
> Signed-off-by: Masami Hiramatsu (Google) <[email protected]>
> ---
> kernel/trace/trace_kprobe.c | 26 +++++++++++++-------------
> 1 file changed, 13 insertions(+), 13 deletions(-)

2024-06-11 00:18:11

by Steven Rostedt

Subject: Re: [PATCH 2/3] tracing/kprobe: Remove unneeded WARN_ON_ONCE() in selftests

On Tue, 11 Jun 2024 06:26:44 +0900
"Masami Hiramatsu (Google)" <[email protected]> wrote:

> From: Masami Hiramatsu (Google) <[email protected]>
>
> Since the kprobe-events selftest shows OK or NG with the reason, the
> WARN_ON_ONCE()s for each place are redundant. Let's remove it.
>
> Signed-off-by: Masami Hiramatsu (Google) <[email protected]>
> ---
> kernel/trace/trace_kprobe.c | 26 +++++++++++++-------------
> 1 file changed, 13 insertions(+), 13 deletions(-)
>
> diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
> index 16383247bdbf..4abed36544d0 100644
> --- a/kernel/trace/trace_kprobe.c
> +++ b/kernel/trace/trace_kprobe.c
> @@ -2023,18 +2023,18 @@ static __init int kprobe_trace_self_tests_init(void)
> pr_info("Testing kprobe tracing: ");
>
> ret = create_or_delete_trace_kprobe("p:testprobe kprobe_trace_selftest_target $stack $stack0 +0($stack)");
> - if (WARN_ON_ONCE(ret)) {
> + if (ret) {
> pr_warn("error on probing function entry.\n");

Actually, you can consolidate this to:

if (WARN_ONCE(ret, "error on probing function entry."))

> warn++;
> } else {
> /* Enable trace point */
> tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
> - if (WARN_ON_ONCE(tk == NULL)) {
> + if (tk == NULL) {
> pr_warn("error on getting new probe.\n");

And this to:

if (WARN_ONCE(tk == NULL, "error on getting new probe."))

end so on.

-- Steve

> warn++;
> } else {
> file = find_trace_probe_file(tk, top_trace_array());
> - if (WARN_ON_ONCE(file == NULL)) {
> + if (file == NULL) {
> pr_warn("error on getting probe file.\n");
> warn++;
> } else
> @@ -2044,18 +2044,18 @@ static __init int kprobe_trace_self_tests_init(void)
> }
>
> ret = create_or_delete_trace_kprobe("r:testprobe2 kprobe_trace_selftest_target $retval");
> - if (WARN_ON_ONCE(ret)) {
> + if (ret) {
> pr_warn("error on probing function return.\n");
> warn++;
> } else {
> /* Enable trace point */
> tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
> - if (WARN_ON_ONCE(tk == NULL)) {
> + if (tk == NULL) {
> pr_warn("error on getting 2nd new probe.\n");
> warn++;
> } else {
> file = find_trace_probe_file(tk, top_trace_array());
> - if (WARN_ON_ONCE(file == NULL)) {
> + if (file == NULL) {
> pr_warn("error on getting probe file.\n");
> warn++;
> } else
> @@ -2079,7 +2079,7 @@ static __init int kprobe_trace_self_tests_init(void)
>
> /* Disable trace points before removing it */
> tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
> - if (WARN_ON_ONCE(tk == NULL)) {
> + if (tk == NULL) {
> pr_warn("error on getting test probe.\n");
> warn++;
> } else {
> @@ -2089,7 +2089,7 @@ static __init int kprobe_trace_self_tests_init(void)
> }
>
> file = find_trace_probe_file(tk, top_trace_array());
> - if (WARN_ON_ONCE(file == NULL)) {
> + if (file == NULL) {
> pr_warn("error on getting probe file.\n");
> warn++;
> } else
> @@ -2098,7 +2098,7 @@ static __init int kprobe_trace_self_tests_init(void)
> }
>
> tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
> - if (WARN_ON_ONCE(tk == NULL)) {
> + if (tk == NULL) {
> pr_warn("error on getting 2nd test probe.\n");
> warn++;
> } else {
> @@ -2108,7 +2108,7 @@ static __init int kprobe_trace_self_tests_init(void)
> }
>
> file = find_trace_probe_file(tk, top_trace_array());
> - if (WARN_ON_ONCE(file == NULL)) {
> + if (file == NULL) {
> pr_warn("error on getting probe file.\n");
> warn++;
> } else
> @@ -2117,20 +2117,20 @@ static __init int kprobe_trace_self_tests_init(void)
> }
>
> ret = create_or_delete_trace_kprobe("-:testprobe");
> - if (WARN_ON_ONCE(ret)) {
> + if (ret) {
> pr_warn("error on deleting a probe.\n");
> warn++;
> }
>
> ret = create_or_delete_trace_kprobe("-:testprobe2");
> - if (WARN_ON_ONCE(ret)) {
> + if (ret) {
> pr_warn("error on deleting a probe.\n");
> warn++;
> }
>
> end:
> ret = dyn_events_release_all(&trace_kprobe_ops);
> - if (WARN_ON_ONCE(ret)) {
> + if (ret) {
> pr_warn("error on cleaning up probes.\n");
> warn++;
> }

2024-06-11 00:18:43

by Masami Hiramatsu

Subject: Re: [PATCH 2/3] tracing/kprobe: Remove unneeded WARN_ON_ONCE() in selftests

On Mon, 10 Jun 2024 17:40:52 -0400
Steven Rostedt <[email protected]> wrote:

> On Tue, 11 Jun 2024 06:26:44 +0900
> "Masami Hiramatsu (Google)" <[email protected]> wrote:
>
> > From: Masami Hiramatsu (Google) <[email protected]>
> >
> > Since the kprobe-events selftest shows OK or NG with the reason, the
> > WARN_ON_ONCE()s for each place are redundant. Let's remove it.
>
> Note, the ktests we run to validate commits, fail when it detects a WARN()
> triggered.
>
> If this fails in any configuration, ktest will not detect it failed.

Hmm, I think there are 2 options,
- remove pr_warn() instead. (WARN_ON_ONCE + pr_warn is redundant)
- Or, remove WARN_ON_ONCE() from each place, but add WARN_ON_ONCE() when
`warn` is not zero.

Thank you,

>
> -- Steve
>
>
> >
> > Signed-off-by: Masami Hiramatsu (Google) <[email protected]>
> > ---
> > kernel/trace/trace_kprobe.c | 26 +++++++++++++-------------
> > 1 file changed, 13 insertions(+), 13 deletions(-)
>


--
Masami Hiramatsu (Google) <[email protected]>

2024-06-11 06:12:10

by Masami Hiramatsu

Subject: Re: [PATCH 2/3] tracing/kprobe: Remove unneeded WARN_ON_ONCE() in selftests

On Mon, 10 Jun 2024 20:18:13 -0400
Steven Rostedt <[email protected]> wrote:

> On Tue, 11 Jun 2024 06:26:44 +0900
> "Masami Hiramatsu (Google)" <[email protected]> wrote:
>
> > From: Masami Hiramatsu (Google) <[email protected]>
> >
> > Since the kprobe-events selftest shows OK or NG with the reason, the
> > WARN_ON_ONCE()s for each place are redundant. Let's remove it.
> >
> > Signed-off-by: Masami Hiramatsu (Google) <[email protected]>
> > ---
> > kernel/trace/trace_kprobe.c | 26 +++++++++++++-------------
> > 1 file changed, 13 insertions(+), 13 deletions(-)
> >
> > diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
> > index 16383247bdbf..4abed36544d0 100644
> > --- a/kernel/trace/trace_kprobe.c
> > +++ b/kernel/trace/trace_kprobe.c
> > @@ -2023,18 +2023,18 @@ static __init int kprobe_trace_self_tests_init(void)
> > pr_info("Testing kprobe tracing: ");
> >
> > ret = create_or_delete_trace_kprobe("p:testprobe kprobe_trace_selftest_target $stack $stack0 +0($stack)");
> > - if (WARN_ON_ONCE(ret)) {
> > + if (ret) {
> > pr_warn("error on probing function entry.\n");
>
> Actually, you can consolidate this to:
>
> if (WARN_ONCE(ret, "error on probing function entry."))

Ahh, OK, let me update it.

>
> > warn++;
> > } else {
> > /* Enable trace point */
> > tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
> > - if (WARN_ON_ONCE(tk == NULL)) {
> > + if (tk == NULL) {
> > pr_warn("error on getting new probe.\n");
>
> And this to:
>
> if (WARN_ONCE(tk == NULL, "error on getting new probe."))

Thank you!

>
> end so on.
>
> -- Steve
>
> > warn++;
> > } else {
> > file = find_trace_probe_file(tk, top_trace_array());
> > - if (WARN_ON_ONCE(file == NULL)) {
> > + if (file == NULL) {
> > pr_warn("error on getting probe file.\n");
> > warn++;
> > } else
> > @@ -2044,18 +2044,18 @@ static __init int kprobe_trace_self_tests_init(void)
> > }
> >
> > ret = create_or_delete_trace_kprobe("r:testprobe2 kprobe_trace_selftest_target $retval");
> > - if (WARN_ON_ONCE(ret)) {
> > + if (ret) {
> > pr_warn("error on probing function return.\n");
> > warn++;
> > } else {
> > /* Enable trace point */
> > tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
> > - if (WARN_ON_ONCE(tk == NULL)) {
> > + if (tk == NULL) {
> > pr_warn("error on getting 2nd new probe.\n");
> > warn++;
> > } else {
> > file = find_trace_probe_file(tk, top_trace_array());
> > - if (WARN_ON_ONCE(file == NULL)) {
> > + if (file == NULL) {
> > pr_warn("error on getting probe file.\n");
> > warn++;
> > } else
> > @@ -2079,7 +2079,7 @@ static __init int kprobe_trace_self_tests_init(void)
> >
> > /* Disable trace points before removing it */
> > tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
> > - if (WARN_ON_ONCE(tk == NULL)) {
> > + if (tk == NULL) {
> > pr_warn("error on getting test probe.\n");
> > warn++;
> > } else {
> > @@ -2089,7 +2089,7 @@ static __init int kprobe_trace_self_tests_init(void)
> > }
> >
> > file = find_trace_probe_file(tk, top_trace_array());
> > - if (WARN_ON_ONCE(file == NULL)) {
> > + if (file == NULL) {
> > pr_warn("error on getting probe file.\n");
> > warn++;
> > } else
> > @@ -2098,7 +2098,7 @@ static __init int kprobe_trace_self_tests_init(void)
> > }
> >
> > tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
> > - if (WARN_ON_ONCE(tk == NULL)) {
> > + if (tk == NULL) {
> > pr_warn("error on getting 2nd test probe.\n");
> > warn++;
> > } else {
> > @@ -2108,7 +2108,7 @@ static __init int kprobe_trace_self_tests_init(void)
> > }
> >
> > file = find_trace_probe_file(tk, top_trace_array());
> > - if (WARN_ON_ONCE(file == NULL)) {
> > + if (file == NULL) {
> > pr_warn("error on getting probe file.\n");
> > warn++;
> > } else
> > @@ -2117,20 +2117,20 @@ static __init int kprobe_trace_self_tests_init(void)
> > }
> >
> > ret = create_or_delete_trace_kprobe("-:testprobe");
> > - if (WARN_ON_ONCE(ret)) {
> > + if (ret) {
> > pr_warn("error on deleting a probe.\n");
> > warn++;
> > }
> >
> > ret = create_or_delete_trace_kprobe("-:testprobe2");
> > - if (WARN_ON_ONCE(ret)) {
> > + if (ret) {
> > pr_warn("error on deleting a probe.\n");
> > warn++;
> > }
> >
> > end:
> > ret = dyn_events_release_all(&trace_kprobe_ops);
> > - if (WARN_ON_ONCE(ret)) {
> > + if (ret) {
> > pr_warn("error on cleaning up probes.\n");
> > warn++;
> > }
>


--
Masami Hiramatsu (Google) <[email protected]>