[Buildroot] [PATCH v2 0/2] packages/linux-tools: perf: allow building perf with libtraceevent

[Buildroot] [PATCH v2 0/2] packages/linux-tools: perf: allow building perf with libtraceevent

[Alexis Lothoré via buildroot]

Hello,
this series is the v2 aiming to allow building perf with libtraceevent
support, in order to be able for example to manipulate and record
uprobes with perf.

This new revision gets a new commit enforcing PKG_CONFIG_LIBDIR for the
perf makefile. I am not sure how I did not get the corresponding error
the first time (maybe it needed some full rebuild to trigger), but I now
see that I fail to build perf with multiple stable kernels if I do not
enforce this variable (if it is not defined, the perf makefile will set
it to a value that is wrong in a buildroot build, see [1]). I found a
similar thread and attempt (see [2]), this series proposes to implement
the second option mentioned in there.

Also, as mentioned in the previous revision, perf may fail to build on
some older kernels because the patch correctly setting pkg-config binary
name has not been backported. I have identified that only 6.6 needed it
(as perf builds start to fail from 6.3, and are fixed in 6.11). The
corresponding stable backport request as been sent (see [3])

@Luca: since all stable kernels should get the relevant fix and then
allow to build perf with libtraceevent support, I eventually chose _not_
to mention any issue in the Kconfig.

[1] https://elixir.bootlin.com/linux/v6.12.36/source/tools/perf/Makefile.perf#L211
[2] https://lore.kernel.org/buildroot/aBk4au4rQpZJMrTQ@vamoirid-laptop/
[3] https://lore.kernel.org/stable/2025070955-discover-tree-644c@gregkh/T/#m394f2c9392da7cfd3ca130af6a7ec8ff6ee4b6bf

To: buildroot@buildroot.org
Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Cc: Luca Ceresoli <luca.ceresoli@bootlin.com>
Cc: Olivier Benjamin <olivier.benjamin@bootlin.com>

Signed-off-by: Alexis Lothoré <alexis.lothore@bootlin.com>
---
Changes in v2:
- enforce PKG_CONFIG_LIBDIR
- Link to v1: https://lore.kernel.org/r/20250625-perf_libtraceevent-v1-1-0bf7620bc6c9@bootlin.com

---
Alexis Lothoré (2):
      package/linux-tools: perf: build with libtraceevent support when it is selected
      packages/linux-tools: perf: enforce PKG_CONFIG_LIBDIR

 package/linux-tools/linux-tool-perf.mk.in | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)
---
base-commit: f28f34e200bbadf0aea32110c72f7199e65fb0b9
change-id: 20250625-perf_libtraceevent-17e46ee28f90

Best regards,
-- 
Alexis Lothoré, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

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[Buildroot] [PATCH v2 1/2] package/linux-tools: perf: build with libtraceevent support when it is selected

[Alexis Lothoré via buildroot]

When trying to perform a custom uprobe recording on a target with perf
built by buildroot, the recording step fails as perf can not record
uprobes without libtraceevent support:

  $ perf probe -x linked_list insert_name index
  Target program is compiled without optimization. Skipping prologue.
  Probe on address 0x808 to force probing at the function entry.

  Added new event:
    probe_linked_list:insert_name (on insert_name in /root/gdb/linked_list with index)

  perf is not linked with libtraceevent, to use the new probe you can use tracefs:

          cd /sys/kernel/tracing/
          echo 1 > events/probe_linked_list/insert_name/enable
          echo 1 > tracing_on
          cat trace_pipe
          Before removing the probe, echo 0 > events/probe_linked_list/insert_name/enable
  $ perf record -e probe_linked_list:insert_name ./linked_list
  event syntax error: 'probe_linked_list:insert_name'
                       \___ unsupported tracepoint

  libtraceevent is necessary for tracepoint support
  Run 'perf list' for a list of valid events

   Usage: perf record [<options>] [<command>]
      or: perf record [<options>] -- <command> [<options>]

      -e, --event <event>   event selector. use 'perf list' to list available events

libtraceevent support for perf has been disabled with commit
b4ab45a5c1db ("package/linux-tools: disable libtracevent detection")
because there was no libtraceevent package in buildroot to replace the
former libtraceevent removed from the kernel sources. Since then, commit
1474f1b34b17 ("package/libtraceevent: new package") has introduced a
libtraceevent package. We can then expose again the possibility to build
perf with libtraceevent support.

Make buildroot perf makefile detect if libtraceevent package has been
enabled, and if so, allow to build perf with libtraceevent support.

Signed-off-by: Alexis Lothoré <alexis.lothore@bootlin.com>
---
Changes in v2:
- no change
---
 package/linux-tools/linux-tool-perf.mk.in | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/package/linux-tools/linux-tool-perf.mk.in b/package/linux-tools/linux-tool-perf.mk.in
index d67318571aa4deefde5b38effe1ade0b87f4627b..1e19ee7f1c4e46d210c079d796f9461f2bfaae08 100644
--- a/package/linux-tools/linux-tool-perf.mk.in
+++ b/package/linux-tools/linux-tool-perf.mk.in
@@ -28,7 +28,6 @@ PERF_MAKE_FLAGS = \
 	NO_LIBPERL=1 \
 	NO_LIBPYTHON=1 \
 	NO_LIBBIONIC=1 \
-	NO_LIBTRACEEVENT=1 \
 	NO_SHELLCHECK=1
 
 # We need to pass an argument to ld for setting the emulation when
@@ -128,6 +127,12 @@ PERF_MAKE_FLAGS += CORESIGHT=1
 # bare "ifdef CORESIGHT" constructs.
 endif
 
+ifeq ($(BR2_PACKAGE_LIBTRACEEVENT),y)
+PERF_DEPENDENCIES += libtraceevent
+else
+PERF_MAKE_FLAGS += NO_LIBTRACEEVENT=1
+endif
+
 # We really do not want to build the perf documentation, because it
 # has stringent requirement on the documentation generation tools,
 # like xmlto and asciidoc), which may be lagging behind on some

-- 
2.50.0

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Re: [Buildroot] [PATCH v2 1/2] package/linux-tools: perf: build with libtraceevent support when it is selected

[Luca Ceresoli via buildroot]

On mercoledì 9 luglio 2025 17:04:14 Ora legale dell’Europa centrale 
Alexis Lothoré wrote:
>When trying to perform a custom uprobe recording on a target with perf
>built by buildroot, the recording step fails as perf can not record
>uprobes without libtraceevent support:
>
>  $ perf probe -x linked_list insert_name index
>  Target program is compiled without optimization. Skipping prologue.
>  Probe on address 0x808 to force probing at the function entry.
>
>  Added new event:
>    probe_linked_list:insert_name (on insert_name in
>/root/gdb/linked_list with index)
>
>  perf is not linked with libtraceevent, to use the new probe you can
>use tracefs:
>
>          cd /sys/kernel/tracing/
>          echo 1 > events/probe_linked_list/insert_name/enable
>          echo 1 > tracing_on
>          cat trace_pipe
>          Before removing the probe, echo 0 >
>events/probe_linked_list/insert_name/enable $ perf record -e
>probe_linked_list:insert_name ./linked_list event syntax error:
>'probe_linked_list:insert_name'
>                       \___ unsupported tracepoint
>
>  libtraceevent is necessary for tracepoint support
>  Run 'perf list' for a list of valid events
>
>   Usage: perf record [<options>] [<command>]
>      or: perf record [<options>] -- <command> [<options>]
>
>      -e, --event <event>   event selector. use 'perf list' to list
>available events
>
>libtraceevent support for perf has been disabled with commit
>b4ab45a5c1db ("package/linux-tools: disable libtracevent detection")
>because there was no libtraceevent package in buildroot to replace the
>former libtraceevent removed from the kernel sources. Since then,
>commit 1474f1b34b17 ("package/libtraceevent: new package") has
>introduced a libtraceevent package. We can then expose again the
>possibility to build perf with libtraceevent support.
>
>Make buildroot perf makefile detect if libtraceevent package has been
>enabled, and if so, allow to build perf with libtraceevent support.
>
>Signed-off-by: Alexis Lothoré <alexis.lothore@bootlin.com>

Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Tested-by: Luca Ceresoli <luca.ceresoli@bootlin.com>

Luca

-- 
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com



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Re: [Buildroot] [PATCH v2 1/2] package/linux-tools: perf: build with libtraceevent support when it is selected

[Julien Olivain via buildroot]

On 09/07/2025 17:04, Alexis Lothoré via buildroot wrote:
> When trying to perform a custom uprobe recording on a target with perf
> built by buildroot, the recording step fails as perf can not record
> uprobes without libtraceevent support:
> 
>   $ perf probe -x linked_list insert_name index
>   Target program is compiled without optimization. Skipping prologue.
>   Probe on address 0x808 to force probing at the function entry.
> 
>   Added new event:
>     probe_linked_list:insert_name (on insert_name in 
> /root/gdb/linked_list with index)
> 
>   perf is not linked with libtraceevent, to use the new probe you can 
> use tracefs:
> 
>           cd /sys/kernel/tracing/
>           echo 1 > events/probe_linked_list/insert_name/enable
>           echo 1 > tracing_on
>           cat trace_pipe
>           Before removing the probe, echo 0 > 
> events/probe_linked_list/insert_name/enable
>   $ perf record -e probe_linked_list:insert_name ./linked_list
>   event syntax error: 'probe_linked_list:insert_name'
>                        \___ unsupported tracepoint
> 
>   libtraceevent is necessary for tracepoint support
>   Run 'perf list' for a list of valid events
> 
>    Usage: perf record [<options>] [<command>]
>       or: perf record [<options>] -- <command> [<options>]
> 
>       -e, --event <event>   event selector. use 'perf list' to list 
> available events
> 
> libtraceevent support for perf has been disabled with commit
> b4ab45a5c1db ("package/linux-tools: disable libtracevent detection")
> because there was no libtraceevent package in buildroot to replace the
> former libtraceevent removed from the kernel sources. Since then, 
> commit
> 1474f1b34b17 ("package/libtraceevent: new package") has introduced a
> libtraceevent package. We can then expose again the possibility to 
> build
> perf with libtraceevent support.
> 
> Make buildroot perf makefile detect if libtraceevent package has been
> enabled, and if so, allow to build perf with libtraceevent support.
> 
> Signed-off-by: Alexis Lothoré <alexis.lothore@bootlin.com>

Series applied to master, thanks.
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Re: [Buildroot] [PATCH v2 1/2] package/linux-tools: perf: build with libtraceevent support when it is selected

[Arnout Vandecappelle via buildroot]

In reply of:
> When trying to perform a custom uprobe recording on a target with perf
> built by buildroot, the recording step fails as perf can not record
> uprobes without libtraceevent support:
> 
>   $ perf probe -x linked_list insert_name index
>   Target program is compiled without optimization. Skipping prologue.
>   Probe on address 0x808 to force probing at the function entry.
> 
>   Added new event:
>     probe_linked_list:insert_name (on insert_name in /root/gdb/linked_list with index)
> 
>   perf is not linked with libtraceevent, to use the new probe you can use tracefs:
> 
>           cd /sys/kernel/tracing/
>           echo 1 > events/probe_linked_list/insert_name/enable
>           echo 1 > tracing_on
>           cat trace_pipe
>           Before removing the probe, echo 0 > events/probe_linked_list/insert_name/enable
>   $ perf record -e probe_linked_list:insert_name ./linked_list
>   event syntax error: 'probe_linked_list:insert_name'
>                        \___ unsupported tracepoint
> 
>   libtraceevent is necessary for tracepoint support
>   Run 'perf list' for a list of valid events
> 
>    Usage: perf record [<options>] [<command>]
>       or: perf record [<options>] -- <command> [<options>]
> 
>       -e, --event <event>   event selector. use 'perf list' to list available events
> 
> libtraceevent support for perf has been disabled with commit
> b4ab45a5c1db ("package/linux-tools: disable libtracevent detection")
> because there was no libtraceevent package in buildroot to replace the
> former libtraceevent removed from the kernel sources. Since then, commit
> 1474f1b34b17 ("package/libtraceevent: new package") has introduced a
> libtraceevent package. We can then expose again the possibility to build
> perf with libtraceevent support.
> 
> Make buildroot perf makefile detect if libtraceevent package has been
> enabled, and if so, allow to build perf with libtraceevent support.
> 
> Signed-off-by: Alexis Lothoré <alexis.lothore@bootlin.com>

Applied to 2025.02.x and 2025.11.x. Thanks

> ---
> Changes in v2:
> - no change
> ---
>  package/linux-tools/linux-tool-perf.mk.in | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/package/linux-tools/linux-tool-perf.mk.in b/package/linux-tools/linux-tool-perf.mk.in
> index d67318571aa4deefde5b38effe1ade0b87f4627b..1e19ee7f1c4e46d210c079d796f9461f2bfaae08 100644
> --- a/package/linux-tools/linux-tool-perf.mk.in
> +++ b/package/linux-tools/linux-tool-perf.mk.in
> @@ -28,7 +28,6 @@ PERF_MAKE_FLAGS = \
>  	NO_LIBPERL=1 \
>  	NO_LIBPYTHON=1 \
>  	NO_LIBBIONIC=1 \
> -	NO_LIBTRACEEVENT=1 \
>  	NO_SHELLCHECK=1
>  
>  # We need to pass an argument to ld for setting the emulation when
> @@ -128,6 +127,12 @@ PERF_MAKE_FLAGS += CORESIGHT=1
>  # bare "ifdef CORESIGHT" constructs.
>  endif
>  
> +ifeq ($(BR2_PACKAGE_LIBTRACEEVENT),y)
> +PERF_DEPENDENCIES += libtraceevent
> +else
> +PERF_MAKE_FLAGS += NO_LIBTRACEEVENT=1
> +endif
> +
>  # We really do not want to build the perf documentation, because it
>  # has stringent requirement on the documentation generation tools,
>  # like xmlto and asciidoc), which may be lagging behind on some
> 
> -- 
> 2.50.0
> 
> _______________________________________________
> buildroot mailing list
> buildroot@buildroot.org
> https://lists.buildroot.org/mailman/listinfo/buildroot
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[Buildroot] [PATCH v2 2/2] packages/linux-tools: perf: enforce PKG_CONFIG_LIBDIR

[Alexis Lothoré via buildroot]

For kernel patched with 440cf77625e3 ("perf: build: Setup
PKG_CONFIG_LIBDIR for cross compilation"), if neither PKG_CONFIG_LIBDIR,
PKG_CONFIG_PATH nor PKG_CONFIG_SYSROOT_DIR are provided, the perf
Makefile while try to set some default value for PKG_CONFIG_LIBDIR,
which will not point correctly to buildroot staging directory. This
issue will lead for example to a failure to find libtraceevent even
if it is correctly enabled and installed in the staging dir, and so it
will make perf fail to build.

Make sure to call the perf make command with PKG_CONFIG_LIBDIR variable
set and pointing to buildroot staging area to make sure to properly
detect perf dependencies.

Signed-off-by: Alexis Lothoré <alexis.lothore@bootlin.com>
---
Changes in v2:
- new patch
---
 package/linux-tools/linux-tool-perf.mk.in | 1 +
 1 file changed, 1 insertion(+)

diff --git a/package/linux-tools/linux-tool-perf.mk.in b/package/linux-tools/linux-tool-perf.mk.in
index 1e19ee7f1c4e46d210c079d796f9461f2bfaae08..3238948d7608920d6c236e47fcdce8a31fb67545 100644
--- a/package/linux-tools/linux-tool-perf.mk.in
+++ b/package/linux-tools/linux-tool-perf.mk.in
@@ -23,6 +23,7 @@ PERF_MAKE_FLAGS = \
 	JOBS=$(PARALLEL_JOBS) \
 	ARCH=$(PERF_ARCH) \
 	DESTDIR=$(TARGET_DIR) \
+	PKG_CONFIG_LIBDIR="$(STAGING_DIR)/usr/lib/pkgconfig" \
 	prefix=/usr \
 	NO_GTK2=1 \
 	NO_LIBPERL=1 \

-- 
2.50.0

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Re: [Buildroot] [PATCH v2 2/2] packages/linux-tools: perf: enforce PKG_CONFIG_LIBDIR

[Luca Ceresoli via buildroot]

On mercoledì 9 luglio 2025 17:04:15 Ora legale dell’Europa centrale 
Alexis Lothoré wrote:
>For kernel patched with 440cf77625e3 ("perf: build: Setup
>PKG_CONFIG_LIBDIR for cross compilation"), if neither
>PKG_CONFIG_LIBDIR, PKG_CONFIG_PATH nor PKG_CONFIG_SYSROOT_DIR are
>provided, the perf Makefile while try to set some default value for
>PKG_CONFIG_LIBDIR, which will not point correctly to buildroot staging
>directory. This issue will lead for example to a failure to find
>libtraceevent even if it is correctly enabled and installed in the
>staging dir, and so it will make perf fail to build.
>
>Make sure to call the perf make command with PKG_CONFIG_LIBDIR variable
>set and pointing to buildroot staging area to make sure to properly
>detect perf dependencies.
>
>Signed-off-by: Alexis Lothoré <alexis.lothore@bootlin.com>

Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Tested-by: Luca Ceresoli <luca.ceresoli@bootlin.com>

Luca

-- 
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com



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Re: [Buildroot] [PATCH v2 2/2] packages/linux-tools: perf: enforce PKG_CONFIG_LIBDIR

[Arnout Vandecappelle via buildroot]

In reply of:
> For kernel patched with 440cf77625e3 ("perf: build: Setup
> PKG_CONFIG_LIBDIR for cross compilation"), if neither PKG_CONFIG_LIBDIR,
> PKG_CONFIG_PATH nor PKG_CONFIG_SYSROOT_DIR are provided, the perf
> Makefile while try to set some default value for PKG_CONFIG_LIBDIR,
> which will not point correctly to buildroot staging directory. This
> issue will lead for example to a failure to find libtraceevent even
> if it is correctly enabled and installed in the staging dir, and so it
> will make perf fail to build.
> 
> Make sure to call the perf make command with PKG_CONFIG_LIBDIR variable
> set and pointing to buildroot staging area to make sure to properly
> detect perf dependencies.
> 
> Signed-off-by: Alexis Lothoré <alexis.lothore@bootlin.com>

Applied to 2025.02.x and 2025.11.x. Thanks

> ---
> Changes in v2:
> - new patch
> ---
>  package/linux-tools/linux-tool-perf.mk.in | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/package/linux-tools/linux-tool-perf.mk.in b/package/linux-tools/linux-tool-perf.mk.in
> index 1e19ee7f1c4e46d210c079d796f9461f2bfaae08..3238948d7608920d6c236e47fcdce8a31fb67545 100644
> --- a/package/linux-tools/linux-tool-perf.mk.in
> +++ b/package/linux-tools/linux-tool-perf.mk.in
> @@ -23,6 +23,7 @@ PERF_MAKE_FLAGS = \
>  	JOBS=$(PARALLEL_JOBS) \
>  	ARCH=$(PERF_ARCH) \
>  	DESTDIR=$(TARGET_DIR) \
> +	PKG_CONFIG_LIBDIR="$(STAGING_DIR)/usr/lib/pkgconfig" \
>  	prefix=/usr \
>  	NO_GTK2=1 \
>  	NO_LIBPERL=1 \
> 
> -- 
> 2.50.0
> 
> _______________________________________________
> buildroot mailing list
> buildroot@buildroot.org
> https://lists.buildroot.org/mailman/listinfo/buildroot
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