<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/tools/lib, branch v6.17.4</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>libperf event: Ensure tracing data is multiple of 8 sized</title>
<updated>2025-10-19T14:37:02+00:00</updated>
<author>
<name>Ian Rogers</name>
<email>irogers@google.com</email>
</author>
<published>2025-08-21T16:38:19+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=fbd0890e88479e379133fe4287039cac1d83b4a6'/>
<id>fbd0890e88479e379133fe4287039cac1d83b4a6</id>
<content type='text'>
[ Upstream commit b39c915a4f365cce6bdc0e538ed95d31823aea8f ]

Perf's synthetic-events.c will ensure 8-byte alignment of tracing
data, writing it after a perf_record_header_tracing_data event.

Add padding to struct perf_record_header_tracing_data to make it 16-byte
rather than 12-byte sized.

Fixes: 055c67ed39887c55 ("perf tools: Move event synthesizing routines to separate .c file")
Reviewed-by: James Clark &lt;james.clark@linaro.org&gt;
Signed-off-by: Ian Rogers &lt;irogers@google.com&gt;
Acked-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Tested-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Athira Rajeev &lt;atrajeev@linux.ibm.com&gt;
Cc: Blake Jones &lt;blakejones@google.com&gt;
Cc: Chun-Tse Shao &lt;ctshao@google.com&gt;
Cc: Collin Funk &lt;collin.funk1@gmail.com&gt;
Cc: Howard Chu &lt;howardchu95@gmail.com&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: Jan Polensky &lt;japo@linux.ibm.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Kan Liang &lt;kan.liang@linux.intel.com&gt;
Cc: Li Huafei &lt;lihuafei1@huawei.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Nam Cao &lt;namcao@linutronix.de&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Steinar H. Gunderson &lt;sesse@google.com&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Link: https://lore.kernel.org/r/20250821163820.1132977-6-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit b39c915a4f365cce6bdc0e538ed95d31823aea8f ]

Perf's synthetic-events.c will ensure 8-byte alignment of tracing
data, writing it after a perf_record_header_tracing_data event.

Add padding to struct perf_record_header_tracing_data to make it 16-byte
rather than 12-byte sized.

Fixes: 055c67ed39887c55 ("perf tools: Move event synthesizing routines to separate .c file")
Reviewed-by: James Clark &lt;james.clark@linaro.org&gt;
Signed-off-by: Ian Rogers &lt;irogers@google.com&gt;
Acked-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Tested-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Athira Rajeev &lt;atrajeev@linux.ibm.com&gt;
Cc: Blake Jones &lt;blakejones@google.com&gt;
Cc: Chun-Tse Shao &lt;ctshao@google.com&gt;
Cc: Collin Funk &lt;collin.funk1@gmail.com&gt;
Cc: Howard Chu &lt;howardchu95@gmail.com&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: Jan Polensky &lt;japo@linux.ibm.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Kan Liang &lt;kan.liang@linux.intel.com&gt;
Cc: Li Huafei &lt;lihuafei1@huawei.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Nam Cao &lt;namcao@linutronix.de&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Steinar H. Gunderson &lt;sesse@google.com&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Link: https://lore.kernel.org/r/20250821163820.1132977-6-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>libbpf: Fix error when st-prefix_ops and ops from differ btf</title>
<updated>2025-10-15T10:03:38+00:00</updated>
<author>
<name>D. Wythe</name>
<email>alibuda@linux.alibaba.com</email>
</author>
<published>2025-09-26T07:17:51+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=3b6a86058efc692227f47860b425bfc04d1627c5'/>
<id>3b6a86058efc692227f47860b425bfc04d1627c5</id>
<content type='text'>
[ Upstream commit 0cc114dc358cf8da2ca23a366e761e89a46ca277 ]

When a module registers a struct_ops, the struct_ops type and its
corresponding map_value type ("bpf_struct_ops_") may reside in different
btf objects, here are four possible case:

+--------+---------------+-------------+---------------------------------+
|        |bpf_struct_ops_| xxx_ops     |                                 |
+--------+---------------+-------------+---------------------------------+
| case 0 | btf_vmlinux   | btf_vmlinux | be used and reg only in vmlinux |
+--------+---------------+-------------+---------------------------------+
| case 1 | btf_vmlinux   | mod_btf     | INVALID                         |
+--------+---------------+-------------+---------------------------------+
| case 2 | mod_btf       | btf_vmlinux | reg in mod but be used both in  |
|        |               |             | vmlinux and mod.                |
+--------+---------------+-------------+---------------------------------+
| case 3 | mod_btf       | mod_btf     | be used and reg only in mod     |
+--------+---------------+-------------+---------------------------------+

Currently we figure out the mod_btf by searching with the struct_ops type,
which makes it impossible to figure out the mod_btf when the struct_ops
type is in btf_vmlinux while it's corresponding map_value type is in
mod_btf (case 2).

The fix is to use the corresponding map_value type ("bpf_struct_ops_")
as the lookup anchor instead of the struct_ops type to figure out the
`btf` and `mod_btf` via find_ksym_btf_id(), and then we can locate
the kern_type_id via btf__find_by_name_kind() with the `btf` we just
obtained from find_ksym_btf_id().

With this change the lookup obtains the correct btf and mod_btf for case 2,
preserves correct behavior for other valid cases, and still fails as
expected for the invalid scenario (case 1).

Fixes: 590a00888250 ("bpf: libbpf: Add STRUCT_OPS support")
Signed-off-by: D. Wythe &lt;alibuda@linux.alibaba.com&gt;
Signed-off-by: Andrii Nakryiko &lt;andrii@kernel.org&gt;
Acked-by: Andrii Nakryiko &lt;andrii@kernel.org&gt;
Acked-by: Martin KaFai Lau &lt;martin.lau@kernel.org&gt;
Link: https://lore.kernel.org/bpf/20250926071751.108293-1-alibuda@linux.alibaba.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 0cc114dc358cf8da2ca23a366e761e89a46ca277 ]

When a module registers a struct_ops, the struct_ops type and its
corresponding map_value type ("bpf_struct_ops_") may reside in different
btf objects, here are four possible case:

+--------+---------------+-------------+---------------------------------+
|        |bpf_struct_ops_| xxx_ops     |                                 |
+--------+---------------+-------------+---------------------------------+
| case 0 | btf_vmlinux   | btf_vmlinux | be used and reg only in vmlinux |
+--------+---------------+-------------+---------------------------------+
| case 1 | btf_vmlinux   | mod_btf     | INVALID                         |
+--------+---------------+-------------+---------------------------------+
| case 2 | mod_btf       | btf_vmlinux | reg in mod but be used both in  |
|        |               |             | vmlinux and mod.                |
+--------+---------------+-------------+---------------------------------+
| case 3 | mod_btf       | mod_btf     | be used and reg only in mod     |
+--------+---------------+-------------+---------------------------------+

Currently we figure out the mod_btf by searching with the struct_ops type,
which makes it impossible to figure out the mod_btf when the struct_ops
type is in btf_vmlinux while it's corresponding map_value type is in
mod_btf (case 2).

The fix is to use the corresponding map_value type ("bpf_struct_ops_")
as the lookup anchor instead of the struct_ops type to figure out the
`btf` and `mod_btf` via find_ksym_btf_id(), and then we can locate
the kern_type_id via btf__find_by_name_kind() with the `btf` we just
obtained from find_ksym_btf_id().

With this change the lookup obtains the correct btf and mod_btf for case 2,
preserves correct behavior for other valid cases, and still fails as
expected for the invalid scenario (case 1).

Fixes: 590a00888250 ("bpf: libbpf: Add STRUCT_OPS support")
Signed-off-by: D. Wythe &lt;alibuda@linux.alibaba.com&gt;
Signed-off-by: Andrii Nakryiko &lt;andrii@kernel.org&gt;
Acked-by: Andrii Nakryiko &lt;andrii@kernel.org&gt;
Acked-by: Martin KaFai Lau &lt;martin.lau@kernel.org&gt;
Link: https://lore.kernel.org/bpf/20250926071751.108293-1-alibuda@linux.alibaba.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>libbpf: Export bpf_object__prepare symbol</title>
<updated>2025-10-15T10:03:20+00:00</updated>
<author>
<name>Mykyta Yatsenko</name>
<email>yatsenko@meta.com</email>
</author>
<published>2025-08-19T21:51:19+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ee9d40eb5825f1e2e4410c44d7ff124b3fc11290'/>
<id>ee9d40eb5825f1e2e4410c44d7ff124b3fc11290</id>
<content type='text'>
[ Upstream commit 2693227c1150d58bf82ef45a394a554373be5286 ]

Add missing LIBBPF_API macro for bpf_object__prepare function to enable
its export. libbpf.map had bpf_object__prepare already listed.

Fixes: 1315c28ed809 ("libbpf: Split bpf object load into prepare/load")
Signed-off-by: Mykyta Yatsenko &lt;yatsenko@meta.com&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Acked-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Link: https://lore.kernel.org/bpf/20250819215119.37795-1-mykyta.yatsenko5@gmail.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 2693227c1150d58bf82ef45a394a554373be5286 ]

Add missing LIBBPF_API macro for bpf_object__prepare function to enable
its export. libbpf.map had bpf_object__prepare already listed.

Fixes: 1315c28ed809 ("libbpf: Split bpf object load into prepare/load")
Signed-off-by: Mykyta Yatsenko &lt;yatsenko@meta.com&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Acked-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Link: https://lore.kernel.org/bpf/20250819215119.37795-1-mykyta.yatsenko5@gmail.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>libbpf: Fix reuse of DEVMAP</title>
<updated>2025-10-15T10:03:19+00:00</updated>
<author>
<name>Yureka Lilian</name>
<email>yuka@yuka.dev</email>
</author>
<published>2025-08-14T18:01:12+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=6737bc841ab4d56702b9b5bdedfb785490265227'/>
<id>6737bc841ab4d56702b9b5bdedfb785490265227</id>
<content type='text'>
[ Upstream commit 6c6b4146deb12d20f42490d5013f2043df942161 ]

Previously, re-using pinned DEVMAP maps would always fail, because
get_map_info on a DEVMAP always returns flags with BPF_F_RDONLY_PROG set,
but BPF_F_RDONLY_PROG being set on a map during creation is invalid.

Thus, ignore the BPF_F_RDONLY_PROG flag in the flags returned from
get_map_info when checking for compatibility with an existing DEVMAP.

The same problem is handled in a third-party ebpf library:
- https://github.com/cilium/ebpf/issues/925
- https://github.com/cilium/ebpf/pull/930

Fixes: 0cdbb4b09a06 ("devmap: Allow map lookups from eBPF")
Signed-off-by: Yureka Lilian &lt;yuka@yuka.dev&gt;
Signed-off-by: Andrii Nakryiko &lt;andrii@kernel.org&gt;
Link: https://lore.kernel.org/bpf/20250814180113.1245565-3-yuka@yuka.dev
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 6c6b4146deb12d20f42490d5013f2043df942161 ]

Previously, re-using pinned DEVMAP maps would always fail, because
get_map_info on a DEVMAP always returns flags with BPF_F_RDONLY_PROG set,
but BPF_F_RDONLY_PROG being set on a map during creation is invalid.

Thus, ignore the BPF_F_RDONLY_PROG flag in the flags returned from
get_map_info when checking for compatibility with an existing DEVMAP.

The same problem is handled in a third-party ebpf library:
- https://github.com/cilium/ebpf/issues/925
- https://github.com/cilium/ebpf/pull/930

Fixes: 0cdbb4b09a06 ("devmap: Allow map lookups from eBPF")
Signed-off-by: Yureka Lilian &lt;yuka@yuka.dev&gt;
Signed-off-by: Andrii Nakryiko &lt;andrii@kernel.org&gt;
Link: https://lore.kernel.org/bpf/20250814180113.1245565-3-yuka@yuka.dev
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf subcmd: avoid crash in exclude_cmds when excludes is empty</title>
<updated>2025-09-13T00:51:35+00:00</updated>
<author>
<name>hupu</name>
<email>hupu.gm@gmail.com</email>
</author>
<published>2025-09-10T08:16:55+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=a5edf3550f4260504b7e0ab3d40d13ffe924b773'/>
<id>a5edf3550f4260504b7e0ab3d40d13ffe924b773</id>
<content type='text'>
When cross-compiling the perf tool for ARM64, `perf help` may crash
with the following assertion failure:

  help.c:122: exclude_cmds: Assertion `cmds-&gt;names[ci] == NULL' failed.

This happens when the perf binary is not named exactly "perf" or when
multiple "perf-*" binaries exist in the same directory. In such cases,
the `excludes` command list can be empty, which leads to the final
assertion in exclude_cmds() being triggered.

Add a simple guard at the beginning of exclude_cmds() to return early
if excludes-&gt;cnt is zero, preventing the crash.

Signed-off-by: hupu &lt;hupu.gm@gmail.com&gt;
Reported-by: Guilherme Amadio &lt;amadio@gentoo.org&gt;
Reviewed-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Link: https://lore.kernel.org/r/20250909094953.106706-1-amadio@gentoo.org
Signed-off-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
When cross-compiling the perf tool for ARM64, `perf help` may crash
with the following assertion failure:

  help.c:122: exclude_cmds: Assertion `cmds-&gt;names[ci] == NULL' failed.

This happens when the perf binary is not named exactly "perf" or when
multiple "perf-*" binaries exist in the same directory. In such cases,
the `excludes` command list can be empty, which leads to the final
assertion in exclude_cmds() being triggered.

Add a simple guard at the beginning of exclude_cmds() to return early
if excludes-&gt;cnt is zero, preventing the crash.

Signed-off-by: hupu &lt;hupu.gm@gmail.com&gt;
Reported-by: Guilherme Amadio &lt;amadio@gentoo.org&gt;
Reviewed-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Link: https://lore.kernel.org/r/20250909094953.106706-1-amadio@gentoo.org
Signed-off-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>libbpf: Add the ability to suppress perf event enablement</title>
<updated>2025-08-07T16:01:41+00:00</updated>
<author>
<name>Ilya Leoshkevich</name>
<email>iii@linux.ibm.com</email>
</author>
<published>2025-08-06T16:22:41+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=9474e27a24a41e55d0ac2b77d8171fddec7dbb87'/>
<id>9474e27a24a41e55d0ac2b77d8171fddec7dbb87</id>
<content type='text'>
Automatically enabling a perf event after attaching a BPF prog to it is
not always desirable.

Add a new "dont_enable" field to struct bpf_perf_event_opts. While
introducing "enable" instead would be nicer in that it would avoid
a double negation in the implementation, it would make
DECLARE_LIBBPF_OPTS() less efficient.

Acked-by: Eduard Zingerman &lt;eddyz87@gmail.com&gt;
Suggested-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Tested-by: Thomas Richter &lt;tmricht@linux.ibm.com&gt;
Co-developed-by: Thomas Richter &lt;tmricht@linux.ibm.com&gt;
Signed-off-by: Thomas Richter &lt;tmricht@linux.ibm.com&gt;
Signed-off-by: Ilya Leoshkevich &lt;iii@linux.ibm.com&gt;
Link: https://lore.kernel.org/r/20250806162417.19666-2-iii@linux.ibm.com
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Automatically enabling a perf event after attaching a BPF prog to it is
not always desirable.

Add a new "dont_enable" field to struct bpf_perf_event_opts. While
introducing "enable" instead would be nicer in that it would avoid
a double negation in the implementation, it would make
DECLARE_LIBBPF_OPTS() less efficient.

Acked-by: Eduard Zingerman &lt;eddyz87@gmail.com&gt;
Suggested-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Tested-by: Thomas Richter &lt;tmricht@linux.ibm.com&gt;
Co-developed-by: Thomas Richter &lt;tmricht@linux.ibm.com&gt;
Signed-off-by: Thomas Richter &lt;tmricht@linux.ibm.com&gt;
Signed-off-by: Ilya Leoshkevich &lt;iii@linux.ibm.com&gt;
Link: https://lore.kernel.org/r/20250806162417.19666-2-iii@linux.ibm.com
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf</title>
<updated>2025-08-02T00:13:26+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2025-08-02T00:13:26+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=a6923c06a3b2e2c534ae28c53a7531e76cc95cfa'/>
<id>a6923c06a3b2e2c534ae28c53a7531e76cc95cfa</id>
<content type='text'>
Pull bpf fixes from Alexei Starovoitov:

 - Fix kCFI failures in JITed BPF code on arm64 (Sami Tolvanen, Puranjay
   Mohan, Mark Rutland, Maxwell Bland)

 - Disallow tail calls between BPF programs that use different cgroup
   local storage maps to prevent out-of-bounds access (Daniel Borkmann)

 - Fix unaligned access in flow_dissector and netfilter BPF programs
   (Paul Chaignon)

 - Avoid possible use of uninitialized mod_len in libbpf (Achill
   Gilgenast)

* tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
  selftests/bpf: Test for unaligned flow_dissector ctx access
  bpf: Improve ctx access verifier error message
  bpf: Check netfilter ctx accesses are aligned
  bpf: Check flow_dissector ctx accesses are aligned
  arm64/cfi,bpf: Support kCFI + BPF on arm64
  cfi: Move BPF CFI types and helpers to generic code
  cfi: add C CFI type macro
  libbpf: Avoid possible use of uninitialized mod_len
  bpf: Fix oob access in cgroup local storage
  bpf: Move cgroup iterator helpers to bpf.h
  bpf: Move bpf map owner out of common struct
  bpf: Add cookie object to bpf maps
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull bpf fixes from Alexei Starovoitov:

 - Fix kCFI failures in JITed BPF code on arm64 (Sami Tolvanen, Puranjay
   Mohan, Mark Rutland, Maxwell Bland)

 - Disallow tail calls between BPF programs that use different cgroup
   local storage maps to prevent out-of-bounds access (Daniel Borkmann)

 - Fix unaligned access in flow_dissector and netfilter BPF programs
   (Paul Chaignon)

 - Avoid possible use of uninitialized mod_len in libbpf (Achill
   Gilgenast)

* tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
  selftests/bpf: Test for unaligned flow_dissector ctx access
  bpf: Improve ctx access verifier error message
  bpf: Check netfilter ctx accesses are aligned
  bpf: Check flow_dissector ctx accesses are aligned
  arm64/cfi,bpf: Support kCFI + BPF on arm64
  cfi: Move BPF CFI types and helpers to generic code
  cfi: add C CFI type macro
  libbpf: Avoid possible use of uninitialized mod_len
  bpf: Fix oob access in cgroup local storage
  bpf: Move cgroup iterator helpers to bpf.h
  bpf: Move bpf map owner out of common struct
  bpf: Add cookie object to bpf maps
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'perf-tools-for-v6.17-2025-08-01' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools</title>
<updated>2025-08-01T23:55:47+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2025-08-01T23:55:47+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=f4f346c3465949ebba80c6cc52cd8d2eeaa545fd'/>
<id>f4f346c3465949ebba80c6cc52cd8d2eeaa545fd</id>
<content type='text'>
Pull perf tools updates from Namhyung Kim:
 "Build-ID processing goodies:

     Build-IDs are content based hashes to link regions of memory to ELF
     files in post processing. They have been available in distros for
     quite a while:

       $ file /bin/bash
       /bin/bash: ELF 64-bit LSB pie executable, x86-64, version 1 (SYSV),
       dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2,
       BuildID[sha1]=707a1c670cd72f8e55ffedfbe94ea98901b7ce3a,
       for GNU/Linux 3.2.0, stripped

     It is possible to ask the kernel to get it from mmap executable
     backing storage at time they are being put in place and send it as
     metadata at that moment to have in perf.data.

     Prefer that across the board to speed up 'record' time - it post
     processes the samples to find binaries touched by any samples and
     to save them with build-ID. It can skip reading build-ID in
     userspace if it comes from the kernel.

  perf record:

   * Make --buildid-mmap default.  The kernel can generate MMAP2 events
     with a build-ID from ELF header.  Use that by default instead of using
     inode and device ID to identify binaries.  It also can be disabled
     with --no-buildid-mmap.

   * Use BPF for -u/--uid option to sample processes belong to a user.
     BPF can track user processes more accurately and the existing logic
     often fails to get the list of processes due to race with reading the
     /proc filesystem.

   * Generate PERF_RECORD_BPF_METADATA when it profiles BPF programs and
     they have variables starting with "bpf_metadata_".  This will help to
     identify BPF objects used in the profile.  This has been supported in
     bpftool for some time and allows the recording of metadata such as
     commit hashes, versions, etc, that now gets recorded in perf.data as
     well.

   * Collect list of DSOs touched in the sample callchains as well as in
     the sample itself.  This would increase the processing time at the end
     of record, but can improve the data quality.

  perf stat:

   * Add a new 'drm' pseudo-PMU support like in 'hwmon'.  It can collect
     DRM usage stats using fdinfo in /proc.

     On my Intel laptop, it shows like below:

       $ perf list drm
       ...

       drm:
         drm-active-stolen-system0
              [Total memory active in one or more engines. Unit: drm_i915]
         drm-active-system0
              [Total memory active in one or more engines. Unit: drm_i915]
         drm-engine-capacity-video
              [Engine capacity. Unit: drm_i915]
         drm-engine-copy
              [Utilization in ns. Unit: drm_i915]
         drm-engine-render
              [Utilization in ns. Unit: drm_i915]
         drm-engine-video
              [Utilization in ns. Unit: drm_i915]
         ...

       $ sudo perf stat -a -e drm-engine-render,drm-engine-video,drm-engine-capacity-video sleep 1

        Performance counter stats for 'system wide':

       48,137,316,988,873 ns       drm-engine-render
           34,452,696,746 ns       drm-engine-video
                       20 capacity drm-engine-capacity-video

              1.002086194 seconds time elapsed

  perf list

   * Add description for software events.  The description is in JSON format
     and the event parser now can handle the software events like others
     (for example, it's case-insensitive and subject to wildcard matching).

       $ perf list software

       List of pre-defined events (to be used in -e or -M):

       software:
         alignment-faults
              [Number of kernel handled memory alignment faults. Unit: software]
         bpf-output
              [An event used by BPF programs to write to the perf ring buffer. Unit: software]
         cgroup-switches
              [Number of context switches to a task in a different cgroup. Unit: software]
         context-switches
              [Number of context switches [This event is an alias of cs]. Unit: software]
         cpu-clock
              [Per-CPU high-resolution timer based event. Unit: software]
         cpu-migrations
              [Number of times a process has migrated to a new CPU [This event is an alias of migrations]. Unit: software]
         cs
              [Number of context switches [This event is an alias of context-switches]. Unit: software]
         dummy
              [A placeholder event that doesn't count anything. Unit: software]
         emulation-faults
              [Number of kernel handled unimplemented instruction faults handled through emulation. Unit: software]
         faults
              [Number of page faults [This event is an alias of page-faults]. Unit: software]
         major-faults
              [Number of major page faults. Major faults require I/O to handle. Unit: software]
         migrations
              [Number of times a process has migrated to a new CPU [This event is an alias of cpu-migrations]. Unit: software]
         minor-faults
              [Number of minor page faults. Minor faults don't require I/O to handle. Unit: software]
         page-faults
              [Number of page faults [This event is an alias of faults]. Unit: software]
         task-clock
              [Per-task high-resolution timer based event. Unit: software]

  perf ftrace:

   * Add -e/--events option to perf ftrace latency to measure latency
     between the two events instead of a function.

       $ sudo perf ftrace latency -ab -e i915_request_wait_begin,i915_request_wait_end --hide-empty -- sleep 1
       #   DURATION     |      COUNT | GRAPH                                |
          256 -  512 us |          4 | ######                               |
            2 -    4 ms |          2 | ###                                  |
            4 -    8 ms |         12 | ###################                  |
            8 -   16 ms |         10 | ################                     |

       # statistics  (in usec)
         total time:               194915
           avg time:                 6961
           max time:                12855
           min time:                  373
              count:                   28

   * Add new function graph tracer options (--graph-opts) to display more
     info like arguments and return value.  They will be passed to the
     kernel ftrace directly.

       $ sudo perf ftrace -G vfs_write --graph-opts retval,retaddr
       # tracer: function_graph
       #
       # CPU  DURATION                  FUNCTION CALLS
       # |     |   |                     |   |   |   |
       ...
       5)               |  mutex_unlock() { /* &lt;-rb_simple_write+0xda/0x150 */
       5)   0.188 us    |    local_clock(); /* &lt;-lock_release+0x2ad/0x440 ret=0x3bf2a3cf90e */
       5)               |    rt_mutex_slowunlock() { /* &lt;-rb_simple_write+0xda/0x150 */
       5)               |      _raw_spin_lock_irqsave() { /* &lt;-rt_mutex_slowunlock+0x4f/0x200 */
       5)   0.123 us    |        preempt_count_add(); /* &lt;-_raw_spin_lock_irqsave+0x23/0x90 ret=0x0 */
       5)   0.128 us    |        local_clock(); /* &lt;-__lock_acquire.isra.0+0x17a/0x740 ret=0x3bf2a3cfc8b */
       5)   0.086 us    |        do_raw_spin_trylock(); /* &lt;-_raw_spin_lock_irqsave+0x4a/0x90 ret=0x1 */
       5)   0.845 us    |      } /* _raw_spin_lock_irqsave ret=0x292 */
       ...

  Misc:

   * Add perf archive --exclude-buildids &lt;FILE&gt; option to skip some binaries.
     The format of the FILE should be same as an output of perf buildid-list.

   * Get rid of dependency of libcrypto.  It was just to get SHA-1 hash so
     implement it directly like in the kernel.  A side effect is that it
     needs -fno-strict-aliasing compiler option (again, like in the kernel).

   * Convert all shell script tests to use bash"

* tag 'perf-tools-for-v6.17-2025-08-01' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools: (179 commits)
  perf record: Cache build-ID of hit DSOs only
  perf test: Ensure lock contention using pipe mode
  perf python: Stop using deprecated PyUnicode_AsString()
  perf list: Skip ABI PMUs when printing pmu values
  perf list: Remove tracepoint printing code
  perf tp_pmu: Add event APIs
  perf tp_pmu: Factor existing tracepoint logic to new file
  perf parse-events: Remove non-json software events
  perf jevents: Add common software event json
  perf tools: Remove libtraceevent in .gitignore
  perf test: Fix comment ordering
  perf sort: Use perf_env to set arch sort keys and header
  perf test: Move PERF_SAMPLE_WEIGHT_STRUCT parsing to common test
  perf sample: Remove arch notion of sample parsing
  perf env: Remove global perf_env
  perf trace: Avoid global perf_env with evsel__env
  perf auxtrace: Pass perf_env from session through to mmap read
  perf machine: Explicitly pass in host perf_env
  perf bench synthesize: Avoid use of global perf_env
  perf top: Make perf_env locally scoped
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull perf tools updates from Namhyung Kim:
 "Build-ID processing goodies:

     Build-IDs are content based hashes to link regions of memory to ELF
     files in post processing. They have been available in distros for
     quite a while:

       $ file /bin/bash
       /bin/bash: ELF 64-bit LSB pie executable, x86-64, version 1 (SYSV),
       dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2,
       BuildID[sha1]=707a1c670cd72f8e55ffedfbe94ea98901b7ce3a,
       for GNU/Linux 3.2.0, stripped

     It is possible to ask the kernel to get it from mmap executable
     backing storage at time they are being put in place and send it as
     metadata at that moment to have in perf.data.

     Prefer that across the board to speed up 'record' time - it post
     processes the samples to find binaries touched by any samples and
     to save them with build-ID. It can skip reading build-ID in
     userspace if it comes from the kernel.

  perf record:

   * Make --buildid-mmap default.  The kernel can generate MMAP2 events
     with a build-ID from ELF header.  Use that by default instead of using
     inode and device ID to identify binaries.  It also can be disabled
     with --no-buildid-mmap.

   * Use BPF for -u/--uid option to sample processes belong to a user.
     BPF can track user processes more accurately and the existing logic
     often fails to get the list of processes due to race with reading the
     /proc filesystem.

   * Generate PERF_RECORD_BPF_METADATA when it profiles BPF programs and
     they have variables starting with "bpf_metadata_".  This will help to
     identify BPF objects used in the profile.  This has been supported in
     bpftool for some time and allows the recording of metadata such as
     commit hashes, versions, etc, that now gets recorded in perf.data as
     well.

   * Collect list of DSOs touched in the sample callchains as well as in
     the sample itself.  This would increase the processing time at the end
     of record, but can improve the data quality.

  perf stat:

   * Add a new 'drm' pseudo-PMU support like in 'hwmon'.  It can collect
     DRM usage stats using fdinfo in /proc.

     On my Intel laptop, it shows like below:

       $ perf list drm
       ...

       drm:
         drm-active-stolen-system0
              [Total memory active in one or more engines. Unit: drm_i915]
         drm-active-system0
              [Total memory active in one or more engines. Unit: drm_i915]
         drm-engine-capacity-video
              [Engine capacity. Unit: drm_i915]
         drm-engine-copy
              [Utilization in ns. Unit: drm_i915]
         drm-engine-render
              [Utilization in ns. Unit: drm_i915]
         drm-engine-video
              [Utilization in ns. Unit: drm_i915]
         ...

       $ sudo perf stat -a -e drm-engine-render,drm-engine-video,drm-engine-capacity-video sleep 1

        Performance counter stats for 'system wide':

       48,137,316,988,873 ns       drm-engine-render
           34,452,696,746 ns       drm-engine-video
                       20 capacity drm-engine-capacity-video

              1.002086194 seconds time elapsed

  perf list

   * Add description for software events.  The description is in JSON format
     and the event parser now can handle the software events like others
     (for example, it's case-insensitive and subject to wildcard matching).

       $ perf list software

       List of pre-defined events (to be used in -e or -M):

       software:
         alignment-faults
              [Number of kernel handled memory alignment faults. Unit: software]
         bpf-output
              [An event used by BPF programs to write to the perf ring buffer. Unit: software]
         cgroup-switches
              [Number of context switches to a task in a different cgroup. Unit: software]
         context-switches
              [Number of context switches [This event is an alias of cs]. Unit: software]
         cpu-clock
              [Per-CPU high-resolution timer based event. Unit: software]
         cpu-migrations
              [Number of times a process has migrated to a new CPU [This event is an alias of migrations]. Unit: software]
         cs
              [Number of context switches [This event is an alias of context-switches]. Unit: software]
         dummy
              [A placeholder event that doesn't count anything. Unit: software]
         emulation-faults
              [Number of kernel handled unimplemented instruction faults handled through emulation. Unit: software]
         faults
              [Number of page faults [This event is an alias of page-faults]. Unit: software]
         major-faults
              [Number of major page faults. Major faults require I/O to handle. Unit: software]
         migrations
              [Number of times a process has migrated to a new CPU [This event is an alias of cpu-migrations]. Unit: software]
         minor-faults
              [Number of minor page faults. Minor faults don't require I/O to handle. Unit: software]
         page-faults
              [Number of page faults [This event is an alias of faults]. Unit: software]
         task-clock
              [Per-task high-resolution timer based event. Unit: software]

  perf ftrace:

   * Add -e/--events option to perf ftrace latency to measure latency
     between the two events instead of a function.

       $ sudo perf ftrace latency -ab -e i915_request_wait_begin,i915_request_wait_end --hide-empty -- sleep 1
       #   DURATION     |      COUNT | GRAPH                                |
          256 -  512 us |          4 | ######                               |
            2 -    4 ms |          2 | ###                                  |
            4 -    8 ms |         12 | ###################                  |
            8 -   16 ms |         10 | ################                     |

       # statistics  (in usec)
         total time:               194915
           avg time:                 6961
           max time:                12855
           min time:                  373
              count:                   28

   * Add new function graph tracer options (--graph-opts) to display more
     info like arguments and return value.  They will be passed to the
     kernel ftrace directly.

       $ sudo perf ftrace -G vfs_write --graph-opts retval,retaddr
       # tracer: function_graph
       #
       # CPU  DURATION                  FUNCTION CALLS
       # |     |   |                     |   |   |   |
       ...
       5)               |  mutex_unlock() { /* &lt;-rb_simple_write+0xda/0x150 */
       5)   0.188 us    |    local_clock(); /* &lt;-lock_release+0x2ad/0x440 ret=0x3bf2a3cf90e */
       5)               |    rt_mutex_slowunlock() { /* &lt;-rb_simple_write+0xda/0x150 */
       5)               |      _raw_spin_lock_irqsave() { /* &lt;-rt_mutex_slowunlock+0x4f/0x200 */
       5)   0.123 us    |        preempt_count_add(); /* &lt;-_raw_spin_lock_irqsave+0x23/0x90 ret=0x0 */
       5)   0.128 us    |        local_clock(); /* &lt;-__lock_acquire.isra.0+0x17a/0x740 ret=0x3bf2a3cfc8b */
       5)   0.086 us    |        do_raw_spin_trylock(); /* &lt;-_raw_spin_lock_irqsave+0x4a/0x90 ret=0x1 */
       5)   0.845 us    |      } /* _raw_spin_lock_irqsave ret=0x292 */
       ...

  Misc:

   * Add perf archive --exclude-buildids &lt;FILE&gt; option to skip some binaries.
     The format of the FILE should be same as an output of perf buildid-list.

   * Get rid of dependency of libcrypto.  It was just to get SHA-1 hash so
     implement it directly like in the kernel.  A side effect is that it
     needs -fno-strict-aliasing compiler option (again, like in the kernel).

   * Convert all shell script tests to use bash"

* tag 'perf-tools-for-v6.17-2025-08-01' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools: (179 commits)
  perf record: Cache build-ID of hit DSOs only
  perf test: Ensure lock contention using pipe mode
  perf python: Stop using deprecated PyUnicode_AsString()
  perf list: Skip ABI PMUs when printing pmu values
  perf list: Remove tracepoint printing code
  perf tp_pmu: Add event APIs
  perf tp_pmu: Factor existing tracepoint logic to new file
  perf parse-events: Remove non-json software events
  perf jevents: Add common software event json
  perf tools: Remove libtraceevent in .gitignore
  perf test: Fix comment ordering
  perf sort: Use perf_env to set arch sort keys and header
  perf test: Move PERF_SAMPLE_WEIGHT_STRUCT parsing to common test
  perf sample: Remove arch notion of sample parsing
  perf env: Remove global perf_env
  perf trace: Avoid global perf_env with evsel__env
  perf auxtrace: Pass perf_env from session through to mmap read
  perf machine: Explicitly pass in host perf_env
  perf bench synthesize: Avoid use of global perf_env
  perf top: Make perf_env locally scoped
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>libbpf: Avoid possible use of uninitialized mod_len</title>
<updated>2025-07-31T18:39:46+00:00</updated>
<author>
<name>Achill Gilgenast</name>
<email>fossdd@pwned.life</email>
</author>
<published>2025-07-29T09:45:53+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=13cb75730b7a8b2dc8fe32874e159b2c7b75efde'/>
<id>13cb75730b7a8b2dc8fe32874e159b2c7b75efde</id>
<content type='text'>
Though mod_len is only read when mod_name != NULL and both are initialized
together, gcc15 produces a warning with -Werror=maybe-uninitialized:

libbpf.c: In function 'find_kernel_btf_id.constprop':
libbpf.c:10100:33: error: 'mod_len' may be used uninitialized [-Werror=maybe-uninitialized]
10100 |                 if (mod_name &amp;&amp; strncmp(mod-&gt;name, mod_name, mod_len) != 0)
      |                                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
libbpf.c:10070:21: note: 'mod_len' was declared here
10070 |         int ret, i, mod_len;
      |                     ^~~~~~~

Silence the false positive.

Signed-off-by: Achill Gilgenast &lt;fossdd@pwned.life&gt;
Acked-by: Yonghong Song &lt;yonghong.song@linux.dev&gt;
Acked-by: Eduard Zingerman &lt;eddyz87@gmail.com&gt;
Link: https://lore.kernel.org/r/20250729094611.2065713-1-fossdd@pwned.life
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Though mod_len is only read when mod_name != NULL and both are initialized
together, gcc15 produces a warning with -Werror=maybe-uninitialized:

libbpf.c: In function 'find_kernel_btf_id.constprop':
libbpf.c:10100:33: error: 'mod_len' may be used uninitialized [-Werror=maybe-uninitialized]
10100 |                 if (mod_name &amp;&amp; strncmp(mod-&gt;name, mod_name, mod_len) != 0)
      |                                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
libbpf.c:10070:21: note: 'mod_len' was declared here
10070 |         int ret, i, mod_len;
      |                     ^~~~~~~

Silence the false positive.

Signed-off-by: Achill Gilgenast &lt;fossdd@pwned.life&gt;
Acked-by: Yonghong Song &lt;yonghong.song@linux.dev&gt;
Acked-by: Eduard Zingerman &lt;eddyz87@gmail.com&gt;
Link: https://lore.kernel.org/r/20250729094611.2065713-1-fossdd@pwned.life
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf parse-events: Support user CPUs mixed with threads/processes</title>
<updated>2025-07-24T20:41:35+00:00</updated>
<author>
<name>Ian Rogers</name>
<email>irogers@google.com</email>
</author>
<published>2025-07-19T03:05:14+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=811082e4b668db9689f8ce927a106036b4ed4e96'/>
<id>811082e4b668db9689f8ce927a106036b4ed4e96</id>
<content type='text'>
Counting events system-wide with a specified CPU prior to this change
worked:
```
$ perf stat -e 'msr/tsc/,msr/tsc,cpu=cpu_core/,msr/tsc,cpu=cpu_atom/' -a sleep 1

  Performance counter stats for 'system wide':

     59,393,419,099      msr/tsc/
     33,927,965,927      msr/tsc,cpu=cpu_core/
     25,465,608,044      msr/tsc,cpu=cpu_atom/
```

However, when counting with process the counts became system wide:
```
$ perf stat -e 'msr/tsc/,msr/tsc,cpu=cpu_core/,msr/tsc,cpu=cpu_atom/' perf test -F 10
 10.1: Basic parsing test                                            : Ok
 10.2: Parsing without PMU name                                      : Ok
 10.3: Parsing with PMU name                                         : Ok

 Performance counter stats for 'perf test -F 10':

        59,233,549      msr/tsc/
        59,227,556      msr/tsc,cpu=cpu_core/
        59,224,053      msr/tsc,cpu=cpu_atom/
```

Make the handling of CPU maps with event parsing clearer. When an
event is parsed creating an evsel the cpus should be either the PMU's
cpumask or user specified CPUs.

Update perf_evlist__propagate_maps so that it doesn't clobber the user
specified CPUs. Try to make the behavior clearer, firstly fix up
missing cpumasks. Next, perform sanity checks and adjustments from the
global evlist CPU requests and for the PMU including simplifying to
the "any CPU"(-1) value. Finally remove the event if the cpumask is
empty.

So that events are opened with a CPU and a thread change stat's
create_perf_stat_counter to give both.

With the change things are fixed:
```
$ perf stat --no-scale -e 'msr/tsc/,msr/tsc,cpu=cpu_core/,msr/tsc,cpu=cpu_atom/' perf test -F 10
 10.1: Basic parsing test                                            : Ok
 10.2: Parsing without PMU name                                      : Ok
 10.3: Parsing with PMU name                                         : Ok

 Performance counter stats for 'perf test -F 10':

        63,704,975      msr/tsc/
        47,060,704      msr/tsc,cpu=cpu_core/                        (4.62%)
        16,640,591      msr/tsc,cpu=cpu_atom/                        (2.18%)
```

However, note the "--no-scale" option is used. This is necessary as
the running time for the event on the counter isn't the same as the
enabled time because the thread doesn't necessarily run on the CPUs
specified for the counter. All counter values are scaled with:

  scaled_value = value * time_enabled / time_running

and so without --no-scale the scaled_value becomes very large. This
problem already exists on hybrid systems for the same reason. Here are
2 runs of the same code with an instructions event that counts the
same on both types of core, there is no real multiplexing happening on
the event:

```
$ perf stat -e instructions perf test -F 10
...
 Performance counter stats for 'perf test -F 10':

        87,896,447      cpu_atom/instructions/                       (14.37%)
        98,171,964      cpu_core/instructions/                       (85.63%)
...
$ perf stat --no-scale -e instructions perf test -F 10
...
 Performance counter stats for 'perf test -F 10':

        13,069,890      cpu_atom/instructions/                       (19.32%)
        83,460,274      cpu_core/instructions/                       (80.68%)
...
```
The scaling has inflated per-PMU instruction counts and the overall
count by 2x.

To fix this the kernel needs changing when a task+CPU event (or just
task event on hybrid) is scheduled out. A fix could be that the state
isn't inactive but off for such events, so that time_enabled counts
don't accumulate on them.

Reviewed-by: Thomas Falcon &lt;thomas.falcon@intel.com&gt;
Signed-off-by: Ian Rogers &lt;irogers@google.com&gt;
Link: https://lore.kernel.org/r/20250719030517.1990983-13-irogers@google.com
Signed-off-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Counting events system-wide with a specified CPU prior to this change
worked:
```
$ perf stat -e 'msr/tsc/,msr/tsc,cpu=cpu_core/,msr/tsc,cpu=cpu_atom/' -a sleep 1

  Performance counter stats for 'system wide':

     59,393,419,099      msr/tsc/
     33,927,965,927      msr/tsc,cpu=cpu_core/
     25,465,608,044      msr/tsc,cpu=cpu_atom/
```

However, when counting with process the counts became system wide:
```
$ perf stat -e 'msr/tsc/,msr/tsc,cpu=cpu_core/,msr/tsc,cpu=cpu_atom/' perf test -F 10
 10.1: Basic parsing test                                            : Ok
 10.2: Parsing without PMU name                                      : Ok
 10.3: Parsing with PMU name                                         : Ok

 Performance counter stats for 'perf test -F 10':

        59,233,549      msr/tsc/
        59,227,556      msr/tsc,cpu=cpu_core/
        59,224,053      msr/tsc,cpu=cpu_atom/
```

Make the handling of CPU maps with event parsing clearer. When an
event is parsed creating an evsel the cpus should be either the PMU's
cpumask or user specified CPUs.

Update perf_evlist__propagate_maps so that it doesn't clobber the user
specified CPUs. Try to make the behavior clearer, firstly fix up
missing cpumasks. Next, perform sanity checks and adjustments from the
global evlist CPU requests and for the PMU including simplifying to
the "any CPU"(-1) value. Finally remove the event if the cpumask is
empty.

So that events are opened with a CPU and a thread change stat's
create_perf_stat_counter to give both.

With the change things are fixed:
```
$ perf stat --no-scale -e 'msr/tsc/,msr/tsc,cpu=cpu_core/,msr/tsc,cpu=cpu_atom/' perf test -F 10
 10.1: Basic parsing test                                            : Ok
 10.2: Parsing without PMU name                                      : Ok
 10.3: Parsing with PMU name                                         : Ok

 Performance counter stats for 'perf test -F 10':

        63,704,975      msr/tsc/
        47,060,704      msr/tsc,cpu=cpu_core/                        (4.62%)
        16,640,591      msr/tsc,cpu=cpu_atom/                        (2.18%)
```

However, note the "--no-scale" option is used. This is necessary as
the running time for the event on the counter isn't the same as the
enabled time because the thread doesn't necessarily run on the CPUs
specified for the counter. All counter values are scaled with:

  scaled_value = value * time_enabled / time_running

and so without --no-scale the scaled_value becomes very large. This
problem already exists on hybrid systems for the same reason. Here are
2 runs of the same code with an instructions event that counts the
same on both types of core, there is no real multiplexing happening on
the event:

```
$ perf stat -e instructions perf test -F 10
...
 Performance counter stats for 'perf test -F 10':

        87,896,447      cpu_atom/instructions/                       (14.37%)
        98,171,964      cpu_core/instructions/                       (85.63%)
...
$ perf stat --no-scale -e instructions perf test -F 10
...
 Performance counter stats for 'perf test -F 10':

        13,069,890      cpu_atom/instructions/                       (19.32%)
        83,460,274      cpu_core/instructions/                       (80.68%)
...
```
The scaling has inflated per-PMU instruction counts and the overall
count by 2x.

To fix this the kernel needs changing when a task+CPU event (or just
task event on hybrid) is scheduled out. A fix could be that the state
isn't inactive but off for such events, so that time_enabled counts
don't accumulate on them.

Reviewed-by: Thomas Falcon &lt;thomas.falcon@intel.com&gt;
Signed-off-by: Ian Rogers &lt;irogers@google.com&gt;
Link: https://lore.kernel.org/r/20250719030517.1990983-13-irogers@google.com
Signed-off-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
</pre>
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</entry>
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