[PATCH v2] selftests/tracing: Fix test_multiple_writes stall

[PATCH v2] selftests/tracing: Fix test_multiple_writes stall

[Fushuai Wang]

When /sys/kernel/tracing/buffer_size_kb is less than 12KB,
the test_multiple_writes test will stall and wait for more
input due to insufficient buffer space.

Check current buffer_size_kb value before the test. If it is
less than 12KB, it temporarily increase the buffer to 12KB,
and restore the original value after the tests are completed.

Fixes: 37f46601383a ("selftests/tracing: Add basic test for trace_marker_raw file")
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Fushuai Wang <wangfushuai@baidu.com>
---
V1 -> V2: Restore buffer_size_kb outside of awk script.

 .../ftrace/test.d/00basic/trace_marker_raw.tc  | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/ftrace/test.d/00basic/trace_marker_raw.tc b/tools/testing/selftests/ftrace/test.d/00basic/trace_marker_raw.tc
index 7daf7292209e..a2c42e13f614 100644
--- a/tools/testing/selftests/ftrace/test.d/00basic/trace_marker_raw.tc
+++ b/tools/testing/selftests/ftrace/test.d/00basic/trace_marker_raw.tc
@@ -89,6 +89,7 @@ test_buffer() {
 	# The id must be four bytes, test that 3 bytes fails a write
 	if echo -n abc > ./trace_marker_raw ; then
 		echo "Too small of write expected to fail but did not"
+		echo ${ORIG} > buffer_size_kb
 		exit_fail
 	fi
 
@@ -99,9 +100,24 @@ test_buffer() {
 
 	if write_buffer 0xdeadbeef $size ; then
 		echo "Too big of write expected to fail but did not"
+		echo ${ORIG} > buffer_size_kb
 		exit_fail
 	fi
 }
 
+ORIG=`cat buffer_size_kb`
+
+# test_multiple_writes test needs at least 12KB buffer
+NEW_SIZE=12
+
+if [ ${ORIG} -lt ${NEW_SIZE} ]; then
+	echo ${NEW_SIZE} > buffer_size_kb
+fi
+
 test_buffer
-test_multiple_writes
+if ! test_multiple_writes; then
+	echo ${ORIG} > buffer_size_kb
+	exit_fail
+fi
+
+echo ${ORIG} > buffer_size_kb
-- 
2.36.1

Re: [PATCH v2] selftests/tracing: Fix test_multiple_writes stall

[Fushuai Wang]

> When /sys/kernel/tracing/buffer_size_kb is less than 12KB,
> the test_multiple_writes test will stall and wait for more
> input due to insufficient buffer space.
> 
> Check current buffer_size_kb value before the test. If it is
> less than 12KB, it temporarily increase the buffer to 12KB,
> and restore the original value after the tests are completed.
> 
> Fixes: 37f46601383a ("selftests/tracing: Add basic test for trace_marker_raw file")
> Suggested-by: Steven Rostedt <rostedt@goodmis.org>
> Signed-off-by: Fushuai Wang <wangfushuai@baidu.com>

Gentle ping.

---
Regards,
WANG

Re: [PATCH v2] selftests/tracing: Fix test_multiple_writes stall

[Steven Rostedt]

On Wed,  7 Jan 2026 11:49:14 +0800
Fushuai Wang <fushuai.wang@linux.dev> wrote:

> > When /sys/kernel/tracing/buffer_size_kb is less than 12KB,
> > the test_multiple_writes test will stall and wait for more
> > input due to insufficient buffer space.
> > 
> > Check current buffer_size_kb value before the test. If it is
> > less than 12KB, it temporarily increase the buffer to 12KB,
> > and restore the original value after the tests are completed.
> > 
> > Fixes: 37f46601383a ("selftests/tracing: Add basic test for trace_marker_raw file")
> > Suggested-by: Steven Rostedt <rostedt@goodmis.org>
> > Signed-off-by: Fushuai Wang <wangfushuai@baidu.com>  
> 
> Gentle ping.
> 

Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>

Shuah,

Care to take this through your tree? It does fix a bug so it likely should
go into the rc releases and not wait for the next merge window.

Thanks,

-- Steve

Re: [PATCH v2] selftests/tracing: Fix test_multiple_writes stall

[Shuah]

On 1/7/26 08:18, Steven Rostedt wrote:
> On Wed,  7 Jan 2026 11:49:14 +0800
> Fushuai Wang <fushuai.wang@linux.dev> wrote:
> 
>>> When /sys/kernel/tracing/buffer_size_kb is less than 12KB,
>>> the test_multiple_writes test will stall and wait for more
>>> input due to insufficient buffer space.
>>>
>>> Check current buffer_size_kb value before the test. If it is
>>> less than 12KB, it temporarily increase the buffer to 12KB,
>>> and restore the original value after the tests are completed.
>>>
>>> Fixes: 37f46601383a ("selftests/tracing: Add basic test for trace_marker_raw file")
>>> Suggested-by: Steven Rostedt <rostedt@goodmis.org>
>>> Signed-off-by: Fushuai Wang <wangfushuai@baidu.com>
>>
>> Gentle ping.
>>
> 
> Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
> 
> Shuah,
> 
> Care to take this through your tree? It does fix a bug so it likely should
> go into the rc releases and not wait for the next merge window.
> 

Yes I can take this through and send this for rc5 or rc6.
But first the following warning needs fixing before I can
apply the patch

WARNING: From:/Signed-off-by: email address mismatch: 'From: Fushuai Wang <fushuai.wang@linux.dev>' != 'Signed-off-by: Fushuai Wang <wangfushuai@baidu.com>'

Fushuai, please send me v3

thanks,
-- Shuah

Re: [PATCH v2] selftests/tracing: Fix test_multiple_writes stall

[Steven Rostedt]

On Thu, 8 Jan 2026 11:27:26 -0700
Shuah <shuah@kernel.org> wrote:

> Yes I can take this through and send this for rc5 or rc6.
> But first the following warning needs fixing before I can
> apply the patch
> 
> WARNING: From:/Signed-off-by: email address mismatch: 'From: Fushuai Wang <fushuai.wang@linux.dev>' != 'Signed-off-by: Fushuai Wang <wangfushuai@baidu.com>'

Hmm, do emails have to match? There's times I used a different SoB than the
From. The From is different than the SoB. The important part I found was to
make sure the name is the same. But I didn't think the email address was
important. And this will become more of an issue, as gmail blocks my
goodmis.org account, so I send with my kernel.org account when my goodmis
is the only one I sign off with. Thus this restriction will fail for me on
my patches.

-- Steve

Re: [PATCH v2] selftests/tracing: Fix test_multiple_writes stall

[Shuah Khan]

On 1/8/26 12:48, Steven Rostedt wrote:
> On Thu, 8 Jan 2026 11:27:26 -0700
> Shuah <shuah@kernel.org> wrote:
> 
>> Yes I can take this through and send this for rc5 or rc6.
>> But first the following warning needs fixing before I can
>> apply the patch
>>
>> WARNING: From:/Signed-off-by: email address mismatch: 'From: Fushuai Wang <fushuai.wang@linux.dev>' != 'Signed-off-by: Fushuai Wang <wangfushuai@baidu.com>'
> 
> Hmm, do emails have to match? There's times I used a different SoB than the
> From. The From is different than the SoB. The important part I found was to
> make sure the name is the same. But I didn't think the email address was
> important. And this will become more of an issue, as gmail blocks my
> goodmis.org account, so I send with my kernel.org account when my goodmis
> is the only one I sign off with. Thus this restriction will fail for me on
> my patches.

I go by the warning - I don't take patches unless From address
matches the SoB.

thanks,
-- Shuah

Re: [PATCH v2] selftests/tracing: Fix test_multiple_writes stall

[Steven Rostedt]

On Thu, 8 Jan 2026 14:03:31 -0700
Shuah Khan <skhan@linuxfoundation.org> wrote:

> On 1/8/26 12:48, Steven Rostedt wrote:
> > On Thu, 8 Jan 2026 11:27:26 -0700
> > Shuah <shuah@kernel.org> wrote:
> >   
> >> Yes I can take this through and send this for rc5 or rc6.
> >> But first the following warning needs fixing before I can
> >> apply the patch
> >>
> >> WARNING: From:/Signed-off-by: email address mismatch: 'From: Fushuai Wang <fushuai.wang@linux.dev>' != 'Signed-off-by: Fushuai Wang <wangfushuai@baidu.com>'  
> > 
> > Hmm, do emails have to match? There's times I used a different SoB than the
> > From. The From is different than the SoB. The important part I found was to
> > make sure the name is the same. But I didn't think the email address was
> > important. And this will become more of an issue, as gmail blocks my
> > goodmis.org account, so I send with my kernel.org account when my goodmis
> > is the only one I sign off with. Thus this restriction will fail for me on
> > my patches.  
> 
> I go by the warning - I don't take patches unless From address
> matches the SoB.

I guess my patches would then fail your requirements ;-)

Anyway, Fushuai, you can add to the top of your commit:

From: Fushuai Wang <wangfushuai@baidu.com>

and that will make the From and SoB match without having to change your
mail client. I usually have that. Because Linus doesn't like my patches
having my company name in it for the "author" but I have it in the SoB to
give credit to the one paying me to do the work.

-- Steve

Re: [PATCH v2] selftests/tracing: Fix test_multiple_writes stall

[Fushuai Wang]

> Anyway, Fushuai, you can add to the top of your commit:
> 
> From: Fushuai Wang <wangfushuai@baidu.com>
> 
> and that will make the From and SoB match without having to change your
> mail client. I usually have that. Because Linus doesn't like my patches
> having my company name in it for the "author" but I have it in the SoB to
> give credit to the one paying me to do the work.

Thanks!
I will send a v3 shortly.

---
Regards,
WANG