<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/tools/lib, branch v6.7.11</title>
<subtitle>Clone of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git</subtitle>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/'/>
<entry>
<title>libbpf: Use OPTS_SET() macro in bpf_xdp_query()</title>
<updated>2024-03-26T22:18:10+00:00</updated>
<author>
<name>Toke Høiland-Jørgensen</name>
<email>toke@redhat.com</email>
</author>
<published>2024-02-06T12:59:22+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=682ddd62abd4bdcee7584246903e7a2df005fe0d'/>
<id>682ddd62abd4bdcee7584246903e7a2df005fe0d</id>
<content type='text'>
[ Upstream commit 92a871ab9fa59a74d013bc04f321026a057618e7 ]

When the feature_flags and xdp_zc_max_segs fields were added to the libbpf
bpf_xdp_query_opts, the code writing them did not use the OPTS_SET() macro.
This causes libbpf to write to those fields unconditionally, which means
that programs compiled against an older version of libbpf (with a smaller
size of the bpf_xdp_query_opts struct) will have its stack corrupted by
libbpf writing out of bounds.

The patch adding the feature_flags field has an early bail out if the
feature_flags field is not part of the opts struct (via the OPTS_HAS)
macro, but the patch adding xdp_zc_max_segs does not. For consistency, this
fix just changes the assignments to both fields to use the OPTS_SET()
macro.

Fixes: 13ce2daa259a ("xsk: add new netlink attribute dedicated for ZC max frags")
Signed-off-by: Toke Høiland-Jørgensen &lt;toke@redhat.com&gt;
Signed-off-by: Andrii Nakryiko &lt;andrii@kernel.org&gt;
Link: https://lore.kernel.org/bpf/20240206125922.1992815-1-toke@redhat.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 92a871ab9fa59a74d013bc04f321026a057618e7 ]

When the feature_flags and xdp_zc_max_segs fields were added to the libbpf
bpf_xdp_query_opts, the code writing them did not use the OPTS_SET() macro.
This causes libbpf to write to those fields unconditionally, which means
that programs compiled against an older version of libbpf (with a smaller
size of the bpf_xdp_query_opts struct) will have its stack corrupted by
libbpf writing out of bounds.

The patch adding the feature_flags field has an early bail out if the
feature_flags field is not part of the opts struct (via the OPTS_HAS)
macro, but the patch adding xdp_zc_max_segs does not. For consistency, this
fix just changes the assignments to both fields to use the OPTS_SET()
macro.

Fixes: 13ce2daa259a ("xsk: add new netlink attribute dedicated for ZC max frags")
Signed-off-by: Toke Høiland-Jørgensen &lt;toke@redhat.com&gt;
Signed-off-by: Andrii Nakryiko &lt;andrii@kernel.org&gt;
Link: https://lore.kernel.org/bpf/20240206125922.1992815-1-toke@redhat.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>libbpf: Add missing LIBBPF_API annotation to libbpf_set_memlock_rlim API</title>
<updated>2024-03-26T22:18:07+00:00</updated>
<author>
<name>Andrii Nakryiko</name>
<email>andrii@kernel.org</email>
</author>
<published>2024-02-01T17:20:24+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=74feabe8243ad01b59bda0e533b0e92d4f46067b'/>
<id>74feabe8243ad01b59bda0e533b0e92d4f46067b</id>
<content type='text'>
[ Upstream commit 93ee1eb85e28d1e35bb059c1f5965d65d5fc83c2 ]

LIBBPF_API annotation seems missing on libbpf_set_memlock_rlim API, so
add it to make this API callable from libbpf's shared library version.

Fixes: e542f2c4cd16 ("libbpf: Auto-bump RLIMIT_MEMLOCK if kernel needs it for BPF")
Fixes: ab9a5a05dc48 ("libbpf: fix up few libbpf.map problems")
Signed-off-by: Andrii Nakryiko &lt;andrii@kernel.org&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Acked-by: Eduard Zingerman &lt;eddyz87@gmail.com&gt;
Link: https://lore.kernel.org/bpf/20240201172027.604869-3-andrii@kernel.org
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 93ee1eb85e28d1e35bb059c1f5965d65d5fc83c2 ]

LIBBPF_API annotation seems missing on libbpf_set_memlock_rlim API, so
add it to make this API callable from libbpf's shared library version.

Fixes: e542f2c4cd16 ("libbpf: Auto-bump RLIMIT_MEMLOCK if kernel needs it for BPF")
Fixes: ab9a5a05dc48 ("libbpf: fix up few libbpf.map problems")
Signed-off-by: Andrii Nakryiko &lt;andrii@kernel.org&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Acked-by: Eduard Zingerman &lt;eddyz87@gmail.com&gt;
Link: https://lore.kernel.org/bpf/20240201172027.604869-3-andrii@kernel.org
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>libbpf: Fix faccessat() usage on Android</title>
<updated>2024-03-26T22:18:06+00:00</updated>
<author>
<name>Andrii Nakryiko</name>
<email>andrii@kernel.org</email>
</author>
<published>2024-01-26T22:09:44+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=14ec1c7a2b460520b860249129ec169fe9af17d2'/>
<id>14ec1c7a2b460520b860249129ec169fe9af17d2</id>
<content type='text'>
[ Upstream commit ad57654053805bf9a62602aaec74cc78edb6f235 ]

Android implementation of libc errors out with -EINVAL in faccessat() if
passed AT_EACCESS ([0]), this leads to ridiculous issue with libbpf
refusing to load /sys/kernel/btf/vmlinux on Androids ([1]). Fix by
detecting Android and redefining AT_EACCESS to 0, it's equivalent on
Android.

  [0] https://android.googlesource.com/platform/bionic/+/refs/heads/android13-release/libc/bionic/faccessat.cpp#50
  [1] https://github.com/libbpf/libbpf-bootstrap/issues/250#issuecomment-1911324250

Fixes: 6a4ab8869d0b ("libbpf: Fix the case of running as non-root with capabilities")
Signed-off-by: Andrii Nakryiko &lt;andrii@kernel.org&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Acked-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Link: https://lore.kernel.org/bpf/20240126220944.2497665-1-andrii@kernel.org
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 ad57654053805bf9a62602aaec74cc78edb6f235 ]

Android implementation of libc errors out with -EINVAL in faccessat() if
passed AT_EACCESS ([0]), this leads to ridiculous issue with libbpf
refusing to load /sys/kernel/btf/vmlinux on Androids ([1]). Fix by
detecting Android and redefining AT_EACCESS to 0, it's equivalent on
Android.

  [0] https://android.googlesource.com/platform/bionic/+/refs/heads/android13-release/libc/bionic/faccessat.cpp#50
  [1] https://github.com/libbpf/libbpf-bootstrap/issues/250#issuecomment-1911324250

Fixes: 6a4ab8869d0b ("libbpf: Fix the case of running as non-root with capabilities")
Signed-off-by: Andrii Nakryiko &lt;andrii@kernel.org&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Acked-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Link: https://lore.kernel.org/bpf/20240126220944.2497665-1-andrii@kernel.org
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>libbpf: Apply map_set_def_max_entries() for inner_maps on creation</title>
<updated>2024-03-26T22:18:04+00:00</updated>
<author>
<name>Andrey Grafin</name>
<email>conquistador@yandex-team.ru</email>
</author>
<published>2024-01-17T13:06:18+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=ced6fa7340de4d3e85d6632d847fc53c95210a37'/>
<id>ced6fa7340de4d3e85d6632d847fc53c95210a37</id>
<content type='text'>
[ Upstream commit f04deb90e516e8e48bf8693397529bc942a9e80b ]

This patch allows to auto create BPF_MAP_TYPE_ARRAY_OF_MAPS and
BPF_MAP_TYPE_HASH_OF_MAPS with values of BPF_MAP_TYPE_PERF_EVENT_ARRAY
by bpf_object__load().

Previous behaviour created a zero filled btf_map_def for inner maps and
tried to use it for a map creation but the linux kernel forbids to create
a BPF_MAP_TYPE_PERF_EVENT_ARRAY map with max_entries=0.

Fixes: 646f02ffdd49 ("libbpf: Add BTF-defined map-in-map support")
Signed-off-by: Andrey Grafin &lt;conquistador@yandex-team.ru&gt;
Signed-off-by: Andrii Nakryiko &lt;andrii@kernel.org&gt;
Acked-by: Yonghong Song &lt;yonghong.song@linux.dev&gt;
Acked-by: Hou Tao &lt;houtao1@huawei.com&gt;
Link: https://lore.kernel.org/bpf/20240117130619.9403-1-conquistador@yandex-team.ru
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&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 f04deb90e516e8e48bf8693397529bc942a9e80b ]

This patch allows to auto create BPF_MAP_TYPE_ARRAY_OF_MAPS and
BPF_MAP_TYPE_HASH_OF_MAPS with values of BPF_MAP_TYPE_PERF_EVENT_ARRAY
by bpf_object__load().

Previous behaviour created a zero filled btf_map_def for inner maps and
tried to use it for a map creation but the linux kernel forbids to create
a BPF_MAP_TYPE_PERF_EVENT_ARRAY map with max_entries=0.

Fixes: 646f02ffdd49 ("libbpf: Add BTF-defined map-in-map support")
Signed-off-by: Andrey Grafin &lt;conquistador@yandex-team.ru&gt;
Signed-off-by: Andrii Nakryiko &lt;andrii@kernel.org&gt;
Acked-by: Yonghong Song &lt;yonghong.song@linux.dev&gt;
Acked-by: Hou Tao &lt;houtao1@huawei.com&gt;
Link: https://lore.kernel.org/bpf/20240117130619.9403-1-conquistador@yandex-team.ru
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>libsubcmd: Fix memory leak in uniq()</title>
<updated>2024-02-05T20:17:05+00:00</updated>
<author>
<name>Ian Rogers</name>
<email>irogers@google.com</email>
</author>
<published>2023-12-08T00:05:13+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=c331709fb533b52f390067c635a219aaac805a02'/>
<id>c331709fb533b52f390067c635a219aaac805a02</id>
<content type='text'>
[ Upstream commit ad30469a841b50dbb541df4d6971d891f703c297 ]

uniq() will write one command name over another causing the overwritten
string to be leaked. Fix by doing a pass that removes duplicates and a
second that removes the holes.

Signed-off-by: Ian Rogers &lt;irogers@google.com&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Chenyuan Mi &lt;cymi20@fudan.edu.cn&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Link: https://lore.kernel.org/r/20231208000515.1693746-1-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 ad30469a841b50dbb541df4d6971d891f703c297 ]

uniq() will write one command name over another causing the overwritten
string to be leaked. Fix by doing a pass that removes duplicates and a
second that removes the holes.

Signed-off-by: Ian Rogers &lt;irogers@google.com&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Chenyuan Mi &lt;cymi20@fudan.edu.cn&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Link: https://lore.kernel.org/r/20231208000515.1693746-1-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 NULL pointer dereference in bpf_object__collect_prog_relos</title>
<updated>2024-02-05T20:16:55+00:00</updated>
<author>
<name>Mingyi Zhang</name>
<email>zhangmingyi5@huawei.com</email>
</author>
<published>2023-12-21T03:39:47+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=ab26541270c722eedf8eefd62797c3ce3d18a91b'/>
<id>ab26541270c722eedf8eefd62797c3ce3d18a91b</id>
<content type='text'>
[ Upstream commit fc3a5534e2a8855427403113cbeb54af5837bbe0 ]

An issue occurred while reading an ELF file in libbpf.c during fuzzing:

	Program received signal SIGSEGV, Segmentation fault.
	0x0000000000958e97 in bpf_object.collect_prog_relos () at libbpf.c:4206
	4206 in libbpf.c
	(gdb) bt
	#0 0x0000000000958e97 in bpf_object.collect_prog_relos () at libbpf.c:4206
	#1 0x000000000094f9d6 in bpf_object.collect_relos () at libbpf.c:6706
	#2 0x000000000092bef3 in bpf_object_open () at libbpf.c:7437
	#3 0x000000000092c046 in bpf_object.open_mem () at libbpf.c:7497
	#4 0x0000000000924afa in LLVMFuzzerTestOneInput () at fuzz/bpf-object-fuzzer.c:16
	#5 0x000000000060be11 in testblitz_engine::fuzzer::Fuzzer::run_one ()
	#6 0x000000000087ad92 in tracing::span::Span::in_scope ()
	#7 0x00000000006078aa in testblitz_engine::fuzzer::util::walkdir ()
	#8 0x00000000005f3217 in testblitz_engine::entrypoint::main::{{closure}} ()
	#9 0x00000000005f2601 in main ()
	(gdb)

scn_data was null at this code(tools/lib/bpf/src/libbpf.c):

	if (rel-&gt;r_offset % BPF_INSN_SZ || rel-&gt;r_offset &gt;= scn_data-&gt;d_size) {

The scn_data is derived from the code above:

	scn = elf_sec_by_idx(obj, sec_idx);
	scn_data = elf_sec_data(obj, scn);

	relo_sec_name = elf_sec_str(obj, shdr-&gt;sh_name);
	sec_name = elf_sec_name(obj, scn);
	if (!relo_sec_name || !sec_name)// don't check whether scn_data is NULL
		return -EINVAL;

In certain special scenarios, such as reading a malformed ELF file,
it is possible that scn_data may be a null pointer

Signed-off-by: Mingyi Zhang &lt;zhangmingyi5@huawei.com&gt;
Signed-off-by: Xin Liu &lt;liuxin350@huawei.com&gt;
Signed-off-by: Changye Wu &lt;wuchangye@huawei.com&gt;
Signed-off-by: Andrii Nakryiko &lt;andrii@kernel.org&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/20231221033947.154564-1-liuxin350@huawei.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 fc3a5534e2a8855427403113cbeb54af5837bbe0 ]

An issue occurred while reading an ELF file in libbpf.c during fuzzing:

	Program received signal SIGSEGV, Segmentation fault.
	0x0000000000958e97 in bpf_object.collect_prog_relos () at libbpf.c:4206
	4206 in libbpf.c
	(gdb) bt
	#0 0x0000000000958e97 in bpf_object.collect_prog_relos () at libbpf.c:4206
	#1 0x000000000094f9d6 in bpf_object.collect_relos () at libbpf.c:6706
	#2 0x000000000092bef3 in bpf_object_open () at libbpf.c:7437
	#3 0x000000000092c046 in bpf_object.open_mem () at libbpf.c:7497
	#4 0x0000000000924afa in LLVMFuzzerTestOneInput () at fuzz/bpf-object-fuzzer.c:16
	#5 0x000000000060be11 in testblitz_engine::fuzzer::Fuzzer::run_one ()
	#6 0x000000000087ad92 in tracing::span::Span::in_scope ()
	#7 0x00000000006078aa in testblitz_engine::fuzzer::util::walkdir ()
	#8 0x00000000005f3217 in testblitz_engine::entrypoint::main::{{closure}} ()
	#9 0x00000000005f2601 in main ()
	(gdb)

scn_data was null at this code(tools/lib/bpf/src/libbpf.c):

	if (rel-&gt;r_offset % BPF_INSN_SZ || rel-&gt;r_offset &gt;= scn_data-&gt;d_size) {

The scn_data is derived from the code above:

	scn = elf_sec_by_idx(obj, sec_idx);
	scn_data = elf_sec_data(obj, scn);

	relo_sec_name = elf_sec_str(obj, shdr-&gt;sh_name);
	sec_name = elf_sec_name(obj, scn);
	if (!relo_sec_name || !sec_name)// don't check whether scn_data is NULL
		return -EINVAL;

In certain special scenarios, such as reading a malformed ELF file,
it is possible that scn_data may be a null pointer

Signed-off-by: Mingyi Zhang &lt;zhangmingyi5@huawei.com&gt;
Signed-off-by: Xin Liu &lt;liuxin350@huawei.com&gt;
Signed-off-by: Changye Wu &lt;wuchangye@huawei.com&gt;
Signed-off-by: Andrii Nakryiko &lt;andrii@kernel.org&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/20231221033947.154564-1-liuxin350@huawei.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>libbpf: Fix potential uninitialized tail padding with LIBBPF_OPTS_RESET</title>
<updated>2024-02-05T20:16:49+00:00</updated>
<author>
<name>Yonghong Song</name>
<email>yonghong.song@linux.dev</email>
</author>
<published>2023-11-07T20:15:11+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=ccc125e4ba6be211d6fd5fcc9ff2d5d00c2a8835'/>
<id>ccc125e4ba6be211d6fd5fcc9ff2d5d00c2a8835</id>
<content type='text'>
[ Upstream commit 7f7c43693c1b46652cfafb7af67ba31726d6ec4e ]

Martin reported that there is a libbpf complaining of non-zero-value tail
padding with LIBBPF_OPTS_RESET macro if struct bpf_netkit_opts is modified
to have a 4-byte tail padding. This only happens to clang compiler.
The commend line is: ./test_progs -t tc_netkit_multi_links
Martin and I did some investigation and found this indeed the case and
the following are the investigation details.

Clang:
  clang version 18.0.0
  &lt;I tried clang15/16/17 and they all have similar results&gt;

tools/lib/bpf/libbpf_common.h:
  #define LIBBPF_OPTS_RESET(NAME, ...)                                      \
        do {                                                                \
                memset(&amp;NAME, 0, sizeof(NAME));                             \
                NAME = (typeof(NAME)) {                                     \
                        .sz = sizeof(NAME),                                 \
                        __VA_ARGS__                                         \
                };                                                          \
        } while (0)

  #endif

tools/lib/bpf/libbpf.h:
  struct bpf_netkit_opts {
        /* size of this struct, for forward/backward compatibility */
        size_t sz;
        __u32 flags;
        __u32 relative_fd;
        __u32 relative_id;
        __u64 expected_revision;
        size_t :0;
  };
  #define bpf_netkit_opts__last_field expected_revision
In the above struct bpf_netkit_opts, there is no tail padding.

prog_tests/tc_netkit.c:
  static void serial_test_tc_netkit_multi_links_target(int mode, int target)
  {
        ...
        LIBBPF_OPTS(bpf_netkit_opts, optl);
        ...
        LIBBPF_OPTS_RESET(optl,
                .flags = BPF_F_BEFORE,
                .relative_fd = bpf_program__fd(skel-&gt;progs.tc1),
        );
        ...
  }

Let us make the following source change, note that we have a 4-byte
tailing padding now.
#  diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
#  index 6cd9c501624f..0dd83910ae9a 100644
#  --- a/tools/lib/bpf/libbpf.h
#  +++ b/tools/lib/bpf/libbpf.h
#  @@ -803,13 +803,13 @@ bpf_program__attach_tcx(const struct bpf_program *prog, int ifindex,
#   struct bpf_netkit_opts {
#        /* size of this struct, for forward/backward compatibility */
#        size_t sz;
#  -       __u32 flags;
#        __u32 relative_fd;
#        __u32 relative_id;
#        __u64 expected_revision;
#  +       __u32 flags;
#        size_t :0;
#   };
#  -#define bpf_netkit_opts__last_field expected_revision
#  +#define bpf_netkit_opts__last_field flags

The clang 18 generated asm code looks like below:
    ;       LIBBPF_OPTS_RESET(optl,
    55e3: 48 8d 7d 98                   leaq    -0x68(%rbp), %rdi
    55e7: 31 f6                         xorl    %esi, %esi
    55e9: ba 20 00 00 00                movl    $0x20, %edx
    55ee: e8 00 00 00 00                callq   0x55f3 &lt;serial_test_tc_netkit_multi_links_target+0x18d3&gt;
    55f3: 48 c7 85 10 fd ff ff 20 00 00 00      movq    $0x20, -0x2f0(%rbp)
    55fe: 48 8b 85 68 ff ff ff          movq    -0x98(%rbp), %rax
    5605: 48 8b 78 18                   movq    0x18(%rax), %rdi
    5609: e8 00 00 00 00                callq   0x560e &lt;serial_test_tc_netkit_multi_links_target+0x18ee&gt;
    560e: 89 85 18 fd ff ff             movl    %eax, -0x2e8(%rbp)
    5614: c7 85 1c fd ff ff 00 00 00 00 movl    $0x0, -0x2e4(%rbp)
    561e: 48 c7 85 20 fd ff ff 00 00 00 00      movq    $0x0, -0x2e0(%rbp)
    5629: c7 85 28 fd ff ff 08 00 00 00 movl    $0x8, -0x2d8(%rbp)
    5633: 48 8b 85 10 fd ff ff          movq    -0x2f0(%rbp), %rax
    563a: 48 89 45 98                   movq    %rax, -0x68(%rbp)
    563e: 48 8b 85 18 fd ff ff          movq    -0x2e8(%rbp), %rax
    5645: 48 89 45 a0                   movq    %rax, -0x60(%rbp)
    5649: 48 8b 85 20 fd ff ff          movq    -0x2e0(%rbp), %rax
    5650: 48 89 45 a8                   movq    %rax, -0x58(%rbp)
    5654: 48 8b 85 28 fd ff ff          movq    -0x2d8(%rbp), %rax
    565b: 48 89 45 b0                   movq    %rax, -0x50(%rbp)
    ;       link = bpf_program__attach_netkit(skel-&gt;progs.tc2, ifindex, &amp;optl);

At -O0 level, the clang compiler creates an intermediate copy.
We have below to store 'flags' with 4-byte store and leave another 4 byte
in the same 8-byte-aligned storage undefined,
    5629: c7 85 28 fd ff ff 08 00 00 00 movl    $0x8, -0x2d8(%rbp)
and later we store 8-byte to the original zero'ed buffer
    5654: 48 8b 85 28 fd ff ff          movq    -0x2d8(%rbp), %rax
    565b: 48 89 45 b0                   movq    %rax, -0x50(%rbp)

This caused a problem as the 4-byte value at [%rbp-0x2dc, %rbp-0x2e0)
may be garbage.

gcc (gcc 11.4) does not have this issue as it does zeroing struct first before
doing assignments:
  ;       LIBBPF_OPTS_RESET(optl,
    50fd: 48 8d 85 40 fc ff ff          leaq    -0x3c0(%rbp), %rax
    5104: ba 20 00 00 00                movl    $0x20, %edx
    5109: be 00 00 00 00                movl    $0x0, %esi
    510e: 48 89 c7                      movq    %rax, %rdi
    5111: e8 00 00 00 00                callq   0x5116 &lt;serial_test_tc_netkit_multi_links_target+0x1522&gt;
    5116: 48 8b 45 f0                   movq    -0x10(%rbp), %rax
    511a: 48 8b 40 18                   movq    0x18(%rax), %rax
    511e: 48 89 c7                      movq    %rax, %rdi
    5121: e8 00 00 00 00                callq   0x5126 &lt;serial_test_tc_netkit_multi_links_target+0x1532&gt;
    5126: 48 c7 85 40 fc ff ff 00 00 00 00      movq    $0x0, -0x3c0(%rbp)
    5131: 48 c7 85 48 fc ff ff 00 00 00 00      movq    $0x0, -0x3b8(%rbp)
    513c: 48 c7 85 50 fc ff ff 00 00 00 00      movq    $0x0, -0x3b0(%rbp)
    5147: 48 c7 85 58 fc ff ff 00 00 00 00      movq    $0x0, -0x3a8(%rbp)
    5152: 48 c7 85 40 fc ff ff 20 00 00 00      movq    $0x20, -0x3c0(%rbp)
    515d: 89 85 48 fc ff ff             movl    %eax, -0x3b8(%rbp)
    5163: c7 85 58 fc ff ff 08 00 00 00 movl    $0x8, -0x3a8(%rbp)
  ;       link = bpf_program__attach_netkit(skel-&gt;progs.tc2, ifindex, &amp;optl);

It is not clear how to resolve the compiler code generation as the compiler
generates correct code w.r.t. how to handle unnamed padding in C standard.
So this patch changed LIBBPF_OPTS_RESET macro to avoid uninitialized tail
padding. We already knows LIBBPF_OPTS macro works on both gcc and clang,
even with tail padding. So LIBBPF_OPTS_RESET is changed to be a
LIBBPF_OPTS followed by a memcpy(), thus avoiding uninitialized tail padding.

The below is asm code generated with this patch and with clang compiler:
    ;       LIBBPF_OPTS_RESET(optl,
    55e3: 48 8d bd 10 fd ff ff          leaq    -0x2f0(%rbp), %rdi
    55ea: 31 f6                         xorl    %esi, %esi
    55ec: ba 20 00 00 00                movl    $0x20, %edx
    55f1: e8 00 00 00 00                callq   0x55f6 &lt;serial_test_tc_netkit_multi_links_target+0x18d6&gt;
    55f6: 48 c7 85 10 fd ff ff 20 00 00 00      movq    $0x20, -0x2f0(%rbp)
    5601: 48 8b 85 68 ff ff ff          movq    -0x98(%rbp), %rax
    5608: 48 8b 78 18                   movq    0x18(%rax), %rdi
    560c: e8 00 00 00 00                callq   0x5611 &lt;serial_test_tc_netkit_multi_links_target+0x18f1&gt;
    5611: 89 85 18 fd ff ff             movl    %eax, -0x2e8(%rbp)
    5617: c7 85 1c fd ff ff 00 00 00 00 movl    $0x0, -0x2e4(%rbp)
    5621: 48 c7 85 20 fd ff ff 00 00 00 00      movq    $0x0, -0x2e0(%rbp)
    562c: c7 85 28 fd ff ff 08 00 00 00 movl    $0x8, -0x2d8(%rbp)
    5636: 48 8b 85 10 fd ff ff          movq    -0x2f0(%rbp), %rax
    563d: 48 89 45 98                   movq    %rax, -0x68(%rbp)
    5641: 48 8b 85 18 fd ff ff          movq    -0x2e8(%rbp), %rax
    5648: 48 89 45 a0                   movq    %rax, -0x60(%rbp)
    564c: 48 8b 85 20 fd ff ff          movq    -0x2e0(%rbp), %rax
    5653: 48 89 45 a8                   movq    %rax, -0x58(%rbp)
    5657: 48 8b 85 28 fd ff ff          movq    -0x2d8(%rbp), %rax
    565e: 48 89 45 b0                   movq    %rax, -0x50(%rbp)
    ;       link = bpf_program__attach_netkit(skel-&gt;progs.tc2, ifindex, &amp;optl);

In the above code, a temporary buffer is zeroed and then has proper value assigned.
Finally, values in temporary buffer are copied to the original variable buffer,
hence tail padding is guaranteed to be 0.

Signed-off-by: Yonghong Song &lt;yonghong.song@linux.dev&gt;
Signed-off-by: Andrii Nakryiko &lt;andrii@kernel.org&gt;
Tested-by: Martin KaFai Lau &lt;martin.lau@kernel.org&gt;
Link: https://lore.kernel.org/bpf/20231107201511.2548645-1-yonghong.song@linux.dev
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 7f7c43693c1b46652cfafb7af67ba31726d6ec4e ]

Martin reported that there is a libbpf complaining of non-zero-value tail
padding with LIBBPF_OPTS_RESET macro if struct bpf_netkit_opts is modified
to have a 4-byte tail padding. This only happens to clang compiler.
The commend line is: ./test_progs -t tc_netkit_multi_links
Martin and I did some investigation and found this indeed the case and
the following are the investigation details.

Clang:
  clang version 18.0.0
  &lt;I tried clang15/16/17 and they all have similar results&gt;

tools/lib/bpf/libbpf_common.h:
  #define LIBBPF_OPTS_RESET(NAME, ...)                                      \
        do {                                                                \
                memset(&amp;NAME, 0, sizeof(NAME));                             \
                NAME = (typeof(NAME)) {                                     \
                        .sz = sizeof(NAME),                                 \
                        __VA_ARGS__                                         \
                };                                                          \
        } while (0)

  #endif

tools/lib/bpf/libbpf.h:
  struct bpf_netkit_opts {
        /* size of this struct, for forward/backward compatibility */
        size_t sz;
        __u32 flags;
        __u32 relative_fd;
        __u32 relative_id;
        __u64 expected_revision;
        size_t :0;
  };
  #define bpf_netkit_opts__last_field expected_revision
In the above struct bpf_netkit_opts, there is no tail padding.

prog_tests/tc_netkit.c:
  static void serial_test_tc_netkit_multi_links_target(int mode, int target)
  {
        ...
        LIBBPF_OPTS(bpf_netkit_opts, optl);
        ...
        LIBBPF_OPTS_RESET(optl,
                .flags = BPF_F_BEFORE,
                .relative_fd = bpf_program__fd(skel-&gt;progs.tc1),
        );
        ...
  }

Let us make the following source change, note that we have a 4-byte
tailing padding now.
#  diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
#  index 6cd9c501624f..0dd83910ae9a 100644
#  --- a/tools/lib/bpf/libbpf.h
#  +++ b/tools/lib/bpf/libbpf.h
#  @@ -803,13 +803,13 @@ bpf_program__attach_tcx(const struct bpf_program *prog, int ifindex,
#   struct bpf_netkit_opts {
#        /* size of this struct, for forward/backward compatibility */
#        size_t sz;
#  -       __u32 flags;
#        __u32 relative_fd;
#        __u32 relative_id;
#        __u64 expected_revision;
#  +       __u32 flags;
#        size_t :0;
#   };
#  -#define bpf_netkit_opts__last_field expected_revision
#  +#define bpf_netkit_opts__last_field flags

The clang 18 generated asm code looks like below:
    ;       LIBBPF_OPTS_RESET(optl,
    55e3: 48 8d 7d 98                   leaq    -0x68(%rbp), %rdi
    55e7: 31 f6                         xorl    %esi, %esi
    55e9: ba 20 00 00 00                movl    $0x20, %edx
    55ee: e8 00 00 00 00                callq   0x55f3 &lt;serial_test_tc_netkit_multi_links_target+0x18d3&gt;
    55f3: 48 c7 85 10 fd ff ff 20 00 00 00      movq    $0x20, -0x2f0(%rbp)
    55fe: 48 8b 85 68 ff ff ff          movq    -0x98(%rbp), %rax
    5605: 48 8b 78 18                   movq    0x18(%rax), %rdi
    5609: e8 00 00 00 00                callq   0x560e &lt;serial_test_tc_netkit_multi_links_target+0x18ee&gt;
    560e: 89 85 18 fd ff ff             movl    %eax, -0x2e8(%rbp)
    5614: c7 85 1c fd ff ff 00 00 00 00 movl    $0x0, -0x2e4(%rbp)
    561e: 48 c7 85 20 fd ff ff 00 00 00 00      movq    $0x0, -0x2e0(%rbp)
    5629: c7 85 28 fd ff ff 08 00 00 00 movl    $0x8, -0x2d8(%rbp)
    5633: 48 8b 85 10 fd ff ff          movq    -0x2f0(%rbp), %rax
    563a: 48 89 45 98                   movq    %rax, -0x68(%rbp)
    563e: 48 8b 85 18 fd ff ff          movq    -0x2e8(%rbp), %rax
    5645: 48 89 45 a0                   movq    %rax, -0x60(%rbp)
    5649: 48 8b 85 20 fd ff ff          movq    -0x2e0(%rbp), %rax
    5650: 48 89 45 a8                   movq    %rax, -0x58(%rbp)
    5654: 48 8b 85 28 fd ff ff          movq    -0x2d8(%rbp), %rax
    565b: 48 89 45 b0                   movq    %rax, -0x50(%rbp)
    ;       link = bpf_program__attach_netkit(skel-&gt;progs.tc2, ifindex, &amp;optl);

At -O0 level, the clang compiler creates an intermediate copy.
We have below to store 'flags' with 4-byte store and leave another 4 byte
in the same 8-byte-aligned storage undefined,
    5629: c7 85 28 fd ff ff 08 00 00 00 movl    $0x8, -0x2d8(%rbp)
and later we store 8-byte to the original zero'ed buffer
    5654: 48 8b 85 28 fd ff ff          movq    -0x2d8(%rbp), %rax
    565b: 48 89 45 b0                   movq    %rax, -0x50(%rbp)

This caused a problem as the 4-byte value at [%rbp-0x2dc, %rbp-0x2e0)
may be garbage.

gcc (gcc 11.4) does not have this issue as it does zeroing struct first before
doing assignments:
  ;       LIBBPF_OPTS_RESET(optl,
    50fd: 48 8d 85 40 fc ff ff          leaq    -0x3c0(%rbp), %rax
    5104: ba 20 00 00 00                movl    $0x20, %edx
    5109: be 00 00 00 00                movl    $0x0, %esi
    510e: 48 89 c7                      movq    %rax, %rdi
    5111: e8 00 00 00 00                callq   0x5116 &lt;serial_test_tc_netkit_multi_links_target+0x1522&gt;
    5116: 48 8b 45 f0                   movq    -0x10(%rbp), %rax
    511a: 48 8b 40 18                   movq    0x18(%rax), %rax
    511e: 48 89 c7                      movq    %rax, %rdi
    5121: e8 00 00 00 00                callq   0x5126 &lt;serial_test_tc_netkit_multi_links_target+0x1532&gt;
    5126: 48 c7 85 40 fc ff ff 00 00 00 00      movq    $0x0, -0x3c0(%rbp)
    5131: 48 c7 85 48 fc ff ff 00 00 00 00      movq    $0x0, -0x3b8(%rbp)
    513c: 48 c7 85 50 fc ff ff 00 00 00 00      movq    $0x0, -0x3b0(%rbp)
    5147: 48 c7 85 58 fc ff ff 00 00 00 00      movq    $0x0, -0x3a8(%rbp)
    5152: 48 c7 85 40 fc ff ff 20 00 00 00      movq    $0x20, -0x3c0(%rbp)
    515d: 89 85 48 fc ff ff             movl    %eax, -0x3b8(%rbp)
    5163: c7 85 58 fc ff ff 08 00 00 00 movl    $0x8, -0x3a8(%rbp)
  ;       link = bpf_program__attach_netkit(skel-&gt;progs.tc2, ifindex, &amp;optl);

It is not clear how to resolve the compiler code generation as the compiler
generates correct code w.r.t. how to handle unnamed padding in C standard.
So this patch changed LIBBPF_OPTS_RESET macro to avoid uninitialized tail
padding. We already knows LIBBPF_OPTS macro works on both gcc and clang,
even with tail padding. So LIBBPF_OPTS_RESET is changed to be a
LIBBPF_OPTS followed by a memcpy(), thus avoiding uninitialized tail padding.

The below is asm code generated with this patch and with clang compiler:
    ;       LIBBPF_OPTS_RESET(optl,
    55e3: 48 8d bd 10 fd ff ff          leaq    -0x2f0(%rbp), %rdi
    55ea: 31 f6                         xorl    %esi, %esi
    55ec: ba 20 00 00 00                movl    $0x20, %edx
    55f1: e8 00 00 00 00                callq   0x55f6 &lt;serial_test_tc_netkit_multi_links_target+0x18d6&gt;
    55f6: 48 c7 85 10 fd ff ff 20 00 00 00      movq    $0x20, -0x2f0(%rbp)
    5601: 48 8b 85 68 ff ff ff          movq    -0x98(%rbp), %rax
    5608: 48 8b 78 18                   movq    0x18(%rax), %rdi
    560c: e8 00 00 00 00                callq   0x5611 &lt;serial_test_tc_netkit_multi_links_target+0x18f1&gt;
    5611: 89 85 18 fd ff ff             movl    %eax, -0x2e8(%rbp)
    5617: c7 85 1c fd ff ff 00 00 00 00 movl    $0x0, -0x2e4(%rbp)
    5621: 48 c7 85 20 fd ff ff 00 00 00 00      movq    $0x0, -0x2e0(%rbp)
    562c: c7 85 28 fd ff ff 08 00 00 00 movl    $0x8, -0x2d8(%rbp)
    5636: 48 8b 85 10 fd ff ff          movq    -0x2f0(%rbp), %rax
    563d: 48 89 45 98                   movq    %rax, -0x68(%rbp)
    5641: 48 8b 85 18 fd ff ff          movq    -0x2e8(%rbp), %rax
    5648: 48 89 45 a0                   movq    %rax, -0x60(%rbp)
    564c: 48 8b 85 20 fd ff ff          movq    -0x2e0(%rbp), %rax
    5653: 48 89 45 a8                   movq    %rax, -0x58(%rbp)
    5657: 48 8b 85 28 fd ff ff          movq    -0x2d8(%rbp), %rax
    565e: 48 89 45 b0                   movq    %rax, -0x50(%rbp)
    ;       link = bpf_program__attach_netkit(skel-&gt;progs.tc2, ifindex, &amp;optl);

In the above code, a temporary buffer is zeroed and then has proper value assigned.
Finally, values in temporary buffer are copied to the original variable buffer,
hence tail padding is guaranteed to be 0.

Signed-off-by: Yonghong Song &lt;yonghong.song@linux.dev&gt;
Signed-off-by: Andrii Nakryiko &lt;andrii@kernel.org&gt;
Tested-by: Martin KaFai Lau &lt;martin.lau@kernel.org&gt;
Link: https://lore.kernel.org/bpf/20231107201511.2548645-1-yonghong.song@linux.dev
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>libapi: Add missing linux/types.h header to get the __u64 type on io.h</title>
<updated>2024-01-25T23:45:20+00:00</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
<email>acme@redhat.com</email>
</author>
<published>2023-11-30T17:11:45+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=a66b6f84213827ee2738c43b01f94e722eff3416'/>
<id>a66b6f84213827ee2738c43b01f94e722eff3416</id>
<content type='text'>
[ Upstream commit af76b2dec0984a079d8497bfa37d29a9b55932e1 ]

There are functions using __u64, so we need to have the linux/types.h
header otherwise we'll break when its not included before api/io.h.

Fixes: e95770af4c4a280f ("tools api: Add a lightweight buffered reading api")
Reviewed-by: Ian Rogers &lt;irogers@google.com&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Link: https://lore.kernel.org/lkml/ZWjDPL+IzPPsuC3X@kernel.org
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 af76b2dec0984a079d8497bfa37d29a9b55932e1 ]

There are functions using __u64, so we need to have the linux/types.h
header otherwise we'll break when its not included before api/io.h.

Fixes: e95770af4c4a280f ("tools api: Add a lightweight buffered reading api")
Reviewed-by: Ian Rogers &lt;irogers@google.com&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Link: https://lore.kernel.org/lkml/ZWjDPL+IzPPsuC3X@kernel.org
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>Merge tag 'perf-tools-for-v6.7-1-2023-11-01' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools</title>
<updated>2023-11-03T18:17:38+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2023-11-03T18:17:38+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=7ab89417ed235f56d84c7893d38d4905e38d2692'/>
<id>7ab89417ed235f56d84c7893d38d4905e38d2692</id>
<content type='text'>
Pull perf tools updates from Namhyung Kim:
 "Build:

   - Compile BPF programs by default if clang (&gt;= 12.0.1) is available
     to enable more features like kernel lock contention, off-cpu
     profiling, kwork, sample filtering and so on.

     This can be disabled by passing BUILD_BPF_SKEL=0 to make.

   - Produce better error messages for bison on debug build (make
     DEBUG=1) by defining YYDEBUG symbol internally.

  perf record:

   - Track sideband events (like FORK/MMAP) from all CPUs even if perf
     record targets a subset of CPUs only (using -C option). Otherwise
     it may lose some information happened on a CPU out of the target
     list.

   - Fix checking raw sched_switch tracepoint argument using system BTF.
     This affects off-cpu profiling which attaches a BPF program to the
     raw tracepoint.

  perf lock contention:

   - Add --lock-cgroup option to see contention by cgroups. This should
     be used with BPF only (using -b option).

       $ sudo perf lock con -ab --lock-cgroup -- sleep 1
        contended   total wait     max wait     avg wait   cgroup

              835     14.06 ms     41.19 us     16.83 us   /system.slice/led.service
               25    122.38 us     13.77 us      4.89 us   /
               44     23.73 us      3.87 us       539 ns   /user.slice/user-657345.slice/session-c4.scope
                1       491 ns       491 ns       491 ns   /system.slice/connectd.service

   - Add -G/--cgroup-filter option to see contention only for given
     cgroups.

     This can be useful when you identified a cgroup in the above
     command and want to investigate more on it. It also works with
     other output options like -t/--threads and -l/--lock-addr.

       $ sudo perf lock con -ab -G /user.slice/user-657345.slice/session-c4.scope -- sleep 1
        contended   total wait     max wait     avg wait         type   caller

                8     77.11 us     17.98 us      9.64 us     spinlock   futex_wake+0xc8
                2     24.56 us     14.66 us     12.28 us     spinlock   tick_do_update_jiffies64+0x25
                1      4.97 us      4.97 us      4.97 us     spinlock   futex_q_lock+0x2a

   - Use per-cpu array for better spinlock tracking. This is to improve
     performance of the BPF program and to avoid nested contention on a
     lock in the BPF hash map.

   - Update callstack check for PowerPC. To find a representative caller
     of a lock, it needs to look up the call stacks. It ends the lookup
     when it sees 0 in the call stack buffer. However, PowerPC call
     stacks can have 0 values in the beginning so skip them when it
     expects valid call stacks after.

  perf kwork:

   - Support 'sched' class (for -k option) so that it can see task
     scheduling event (using sched_switch tracepoint) as well as irq and
     workqueue items.

   - Add perf kwork top subcommand to show more accurate cpu utilization
     with sched class above. It works both with a recorded data (using
     perf kwork record command) and BPF (using -b option). Unlike perf
     top command, it does not support interactive mode (yet).

       $ sudo perf kwork top -b -k sched
       Starting trace, Hit &lt;Ctrl+C&gt; to stop and report
       ^C
       Total  : 160702.425 ms, 8 cpus
       %Cpu(s):  36.00% id,   0.00% hi,   0.00% si
       %Cpu0   [||||||||||||||||||              61.66%]
       %Cpu1   [||||||||||||||||||              61.27%]
       %Cpu2   [|||||||||||||||||||             66.40%]
       %Cpu3   [||||||||||||||||||              61.28%]
       %Cpu4   [||||||||||||||||||              61.82%]
       %Cpu5   [|||||||||||||||||||||||         77.41%]
       %Cpu6   [||||||||||||||||||              61.73%]
       %Cpu7   [||||||||||||||||||              63.25%]

             PID     SPID    %CPU           RUNTIME  COMMMAND
         -------------------------------------------------------------
               0        0   38.72       8089.463 ms  [swapper/1]
               0        0   38.71       8084.547 ms  [swapper/3]
               0        0   38.33       8007.532 ms  [swapper/0]
               0        0   38.26       7992.985 ms  [swapper/6]
               0        0   38.17       7971.865 ms  [swapper/4]
               0        0   36.74       7447.765 ms  [swapper/7]
               0        0   33.59       6486.942 ms  [swapper/2]
               0        0   22.58       3771.268 ms  [swapper/5]
            9545     9351    2.48        447.136 ms  sched-messaging
            9574     9351    2.09        418.583 ms  sched-messaging
            9724     9351    2.05        372.407 ms  sched-messaging
            9531     9351    2.01        368.804 ms  sched-messaging
            9512     9351    2.00        362.250 ms  sched-messaging
            9514     9351    1.95        357.767 ms  sched-messaging
            9538     9351    1.86        384.476 ms  sched-messaging
            9712     9351    1.84        386.490 ms  sched-messaging
            9723     9351    1.83        380.021 ms  sched-messaging
            9722     9351    1.82        382.738 ms  sched-messaging
            9517     9351    1.81        354.794 ms  sched-messaging
            9559     9351    1.79        344.305 ms  sched-messaging
            9725     9351    1.77        365.315 ms  sched-messaging
       &lt;SNIP&gt;

   - Add hard/soft-irq statistics to perf kwork top. This will show the
     total CPU utilization with IRQ stats like below:

       $ sudo perf kwork top -b -k sched,irq,softirq
       Starting trace, Hit &lt;Ctrl+C&gt; to stop and report
       ^C
       Total  :  12554.889 ms, 8 cpus
       %Cpu(s):  96.23% id,   0.10% hi,   0.19% si      &lt;---- here
       %Cpu0   [|                                4.60%]
       %Cpu1   [|                                4.59%]
       %Cpu2   [                                 2.73%]
       %Cpu3   [|                                3.81%]
       &lt;SNIP&gt;

  perf bench:

   - Add -G/--cgroups option to perf bench sched pipe. The pipe bench is
     good to measure context switch overhead. With this option, it puts
     the reader and writer tasks in separate cgroups to enforce context
     switch between two different cgroups.

     Also it needs to set CPU affinity of the tasks in a CPU to
     accurately measure the impact of cgroup context switches.

       $ sudo perf stat -e context-switches,cgroup-switches -- \
       &gt; taskset -c 0 perf bench sched pipe -l 100000
       # Running 'sched/pipe' benchmark:
       # Executed 100000 pipe operations between two processes

            Total time: 0.307 [sec]

              3.078180 usecs/op
                324867 ops/sec

        Performance counter stats for 'taskset -c 0 perf bench sched pipe -l 100000':

                  200,026      context-switches
                       63      cgroup-switches

              0.321637922 seconds time elapsed

     You can see small number of cgroup-switches because both write and
     read tasks are in the same cgroup.

       $ sudo mkdir /sys/fs/cgroup/{AAA,BBB}

       $ sudo perf stat -e context-switches,cgroup-switches -- \
       &gt; taskset -c 0 perf bench sched pipe -l 100000 -G AAA,BBB
       # Running 'sched/pipe' benchmark:
       # Executed 100000 pipe operations between two processes

            Total time: 0.351 [sec]

              3.512990 usecs/op
                284657 ops/sec

        Performance counter stats for 'taskset -c 0 perf bench sched pipe -l 100000 -G AAA,BBB':

                  200,020      context-switches
                  200,019      cgroup-switches

              0.365034567 seconds time elapsed

     Now context-switches and cgroup-switches are almost same. And you
     can see the pipe operation took little more.

   - Kill child processes when perf bench sched messaging exited
     abnormally. Otherwise it'd leave the child doing unnecessary work.

  perf test:

   - Fix various shellcheck issues on the tests written in shell script.

   - Skip tests when condition is not satisfied:
      - object code reading test for non-text section addresses.
      - CoreSight test if cs_etm// event is not available.
      - lock contention test if not enough CPUs.

  Event parsing:

   - Make PMU alias name loading lazy to reduce the startup time in the
     event parsing code for perf record, stat and others in the general
     case.

   - Lazily compute PMU default config. In the same sense, delay PMU
     initialization until it's really needed to reduce the startup cost.

   - Fix event term values that are raw events. The event specification
     can have several terms including event name. But sometimes it
     clashes with raw event encoding which starts with 'r' and has
     hex-digits.

     For example, an event named 'read' should be processed as a normal
     event but it was mis-treated as a raw encoding and caused a
     failure.

       $ perf stat -e 'uncore_imc_free_running/event=read/' -a sleep 1
       event syntax error: '..nning/event=read/'
                                         \___ parser error
       Run 'perf list' for a list of valid events

        Usage: perf stat [&lt;options&gt;] [&lt;command&gt;]

           -e, --event &lt;event&gt; event selector. use 'perf list' to list available events

  Event metrics:

   - Add "Compat" regex to match event with multiple identifiers.

   - Usual updates for Intel, Power10, Arm telemetry/CMN and AmpereOne.

  Misc:

   - Assorted memory leak fixes and footprint reduction.

   - Add "bpf_skeletons" to perf version --build-options so that users
     can check whether their perf tools have BPF support easily.

   - Fix unaligned access in Intel-PT packet decoder found by
     undefined-behavior sanitizer.

   - Avoid frequency mode for the dummy event. Surprisingly it'd impact
     kernel timer tick handler performance by force iterating all PMU
     events.

   - Update bash shell completion for events and metrics"

* tag 'perf-tools-for-v6.7-1-2023-11-01' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools: (187 commits)
  perf vendor events intel: Update tsx_cycles_per_elision metrics
  perf vendor events intel: Update bonnell version number to v5
  perf vendor events intel: Update westmereex events to v4
  perf vendor events intel: Update meteorlake events to v1.06
  perf vendor events intel: Update knightslanding events to v16
  perf vendor events intel: Add typo fix for ivybridge FP
  perf vendor events intel: Update a spelling in haswell/haswellx
  perf vendor events intel: Update emeraldrapids to v1.01
  perf vendor events intel: Update alderlake/alderlake events to v1.23
  perf build: Disable BPF skeletons if clang version is &lt; 12.0.1
  perf callchain: Fix spelling mistake "statisitcs" -&gt; "statistics"
  perf report: Fix spelling mistake "heirachy" -&gt; "hierarchy"
  perf python: Fix binding linkage due to rename and move of evsel__increase_rlimit()
  perf tests: test_arm_coresight: Simplify source iteration
  perf vendor events intel: Add tigerlake two metrics
  perf vendor events intel: Add broadwellde two metrics
  perf vendor events intel: Fix broadwellde tma_info_system_dram_bw_use metric
  perf mem_info: Add and use map_symbol__exit and addr_map_symbol__exit
  perf callchain: Minor layout changes to callchain_list
  perf callchain: Make brtype_stat in callchain_list optional
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull perf tools updates from Namhyung Kim:
 "Build:

   - Compile BPF programs by default if clang (&gt;= 12.0.1) is available
     to enable more features like kernel lock contention, off-cpu
     profiling, kwork, sample filtering and so on.

     This can be disabled by passing BUILD_BPF_SKEL=0 to make.

   - Produce better error messages for bison on debug build (make
     DEBUG=1) by defining YYDEBUG symbol internally.

  perf record:

   - Track sideband events (like FORK/MMAP) from all CPUs even if perf
     record targets a subset of CPUs only (using -C option). Otherwise
     it may lose some information happened on a CPU out of the target
     list.

   - Fix checking raw sched_switch tracepoint argument using system BTF.
     This affects off-cpu profiling which attaches a BPF program to the
     raw tracepoint.

  perf lock contention:

   - Add --lock-cgroup option to see contention by cgroups. This should
     be used with BPF only (using -b option).

       $ sudo perf lock con -ab --lock-cgroup -- sleep 1
        contended   total wait     max wait     avg wait   cgroup

              835     14.06 ms     41.19 us     16.83 us   /system.slice/led.service
               25    122.38 us     13.77 us      4.89 us   /
               44     23.73 us      3.87 us       539 ns   /user.slice/user-657345.slice/session-c4.scope
                1       491 ns       491 ns       491 ns   /system.slice/connectd.service

   - Add -G/--cgroup-filter option to see contention only for given
     cgroups.

     This can be useful when you identified a cgroup in the above
     command and want to investigate more on it. It also works with
     other output options like -t/--threads and -l/--lock-addr.

       $ sudo perf lock con -ab -G /user.slice/user-657345.slice/session-c4.scope -- sleep 1
        contended   total wait     max wait     avg wait         type   caller

                8     77.11 us     17.98 us      9.64 us     spinlock   futex_wake+0xc8
                2     24.56 us     14.66 us     12.28 us     spinlock   tick_do_update_jiffies64+0x25
                1      4.97 us      4.97 us      4.97 us     spinlock   futex_q_lock+0x2a

   - Use per-cpu array for better spinlock tracking. This is to improve
     performance of the BPF program and to avoid nested contention on a
     lock in the BPF hash map.

   - Update callstack check for PowerPC. To find a representative caller
     of a lock, it needs to look up the call stacks. It ends the lookup
     when it sees 0 in the call stack buffer. However, PowerPC call
     stacks can have 0 values in the beginning so skip them when it
     expects valid call stacks after.

  perf kwork:

   - Support 'sched' class (for -k option) so that it can see task
     scheduling event (using sched_switch tracepoint) as well as irq and
     workqueue items.

   - Add perf kwork top subcommand to show more accurate cpu utilization
     with sched class above. It works both with a recorded data (using
     perf kwork record command) and BPF (using -b option). Unlike perf
     top command, it does not support interactive mode (yet).

       $ sudo perf kwork top -b -k sched
       Starting trace, Hit &lt;Ctrl+C&gt; to stop and report
       ^C
       Total  : 160702.425 ms, 8 cpus
       %Cpu(s):  36.00% id,   0.00% hi,   0.00% si
       %Cpu0   [||||||||||||||||||              61.66%]
       %Cpu1   [||||||||||||||||||              61.27%]
       %Cpu2   [|||||||||||||||||||             66.40%]
       %Cpu3   [||||||||||||||||||              61.28%]
       %Cpu4   [||||||||||||||||||              61.82%]
       %Cpu5   [|||||||||||||||||||||||         77.41%]
       %Cpu6   [||||||||||||||||||              61.73%]
       %Cpu7   [||||||||||||||||||              63.25%]

             PID     SPID    %CPU           RUNTIME  COMMMAND
         -------------------------------------------------------------
               0        0   38.72       8089.463 ms  [swapper/1]
               0        0   38.71       8084.547 ms  [swapper/3]
               0        0   38.33       8007.532 ms  [swapper/0]
               0        0   38.26       7992.985 ms  [swapper/6]
               0        0   38.17       7971.865 ms  [swapper/4]
               0        0   36.74       7447.765 ms  [swapper/7]
               0        0   33.59       6486.942 ms  [swapper/2]
               0        0   22.58       3771.268 ms  [swapper/5]
            9545     9351    2.48        447.136 ms  sched-messaging
            9574     9351    2.09        418.583 ms  sched-messaging
            9724     9351    2.05        372.407 ms  sched-messaging
            9531     9351    2.01        368.804 ms  sched-messaging
            9512     9351    2.00        362.250 ms  sched-messaging
            9514     9351    1.95        357.767 ms  sched-messaging
            9538     9351    1.86        384.476 ms  sched-messaging
            9712     9351    1.84        386.490 ms  sched-messaging
            9723     9351    1.83        380.021 ms  sched-messaging
            9722     9351    1.82        382.738 ms  sched-messaging
            9517     9351    1.81        354.794 ms  sched-messaging
            9559     9351    1.79        344.305 ms  sched-messaging
            9725     9351    1.77        365.315 ms  sched-messaging
       &lt;SNIP&gt;

   - Add hard/soft-irq statistics to perf kwork top. This will show the
     total CPU utilization with IRQ stats like below:

       $ sudo perf kwork top -b -k sched,irq,softirq
       Starting trace, Hit &lt;Ctrl+C&gt; to stop and report
       ^C
       Total  :  12554.889 ms, 8 cpus
       %Cpu(s):  96.23% id,   0.10% hi,   0.19% si      &lt;---- here
       %Cpu0   [|                                4.60%]
       %Cpu1   [|                                4.59%]
       %Cpu2   [                                 2.73%]
       %Cpu3   [|                                3.81%]
       &lt;SNIP&gt;

  perf bench:

   - Add -G/--cgroups option to perf bench sched pipe. The pipe bench is
     good to measure context switch overhead. With this option, it puts
     the reader and writer tasks in separate cgroups to enforce context
     switch between two different cgroups.

     Also it needs to set CPU affinity of the tasks in a CPU to
     accurately measure the impact of cgroup context switches.

       $ sudo perf stat -e context-switches,cgroup-switches -- \
       &gt; taskset -c 0 perf bench sched pipe -l 100000
       # Running 'sched/pipe' benchmark:
       # Executed 100000 pipe operations between two processes

            Total time: 0.307 [sec]

              3.078180 usecs/op
                324867 ops/sec

        Performance counter stats for 'taskset -c 0 perf bench sched pipe -l 100000':

                  200,026      context-switches
                       63      cgroup-switches

              0.321637922 seconds time elapsed

     You can see small number of cgroup-switches because both write and
     read tasks are in the same cgroup.

       $ sudo mkdir /sys/fs/cgroup/{AAA,BBB}

       $ sudo perf stat -e context-switches,cgroup-switches -- \
       &gt; taskset -c 0 perf bench sched pipe -l 100000 -G AAA,BBB
       # Running 'sched/pipe' benchmark:
       # Executed 100000 pipe operations between two processes

            Total time: 0.351 [sec]

              3.512990 usecs/op
                284657 ops/sec

        Performance counter stats for 'taskset -c 0 perf bench sched pipe -l 100000 -G AAA,BBB':

                  200,020      context-switches
                  200,019      cgroup-switches

              0.365034567 seconds time elapsed

     Now context-switches and cgroup-switches are almost same. And you
     can see the pipe operation took little more.

   - Kill child processes when perf bench sched messaging exited
     abnormally. Otherwise it'd leave the child doing unnecessary work.

  perf test:

   - Fix various shellcheck issues on the tests written in shell script.

   - Skip tests when condition is not satisfied:
      - object code reading test for non-text section addresses.
      - CoreSight test if cs_etm// event is not available.
      - lock contention test if not enough CPUs.

  Event parsing:

   - Make PMU alias name loading lazy to reduce the startup time in the
     event parsing code for perf record, stat and others in the general
     case.

   - Lazily compute PMU default config. In the same sense, delay PMU
     initialization until it's really needed to reduce the startup cost.

   - Fix event term values that are raw events. The event specification
     can have several terms including event name. But sometimes it
     clashes with raw event encoding which starts with 'r' and has
     hex-digits.

     For example, an event named 'read' should be processed as a normal
     event but it was mis-treated as a raw encoding and caused a
     failure.

       $ perf stat -e 'uncore_imc_free_running/event=read/' -a sleep 1
       event syntax error: '..nning/event=read/'
                                         \___ parser error
       Run 'perf list' for a list of valid events

        Usage: perf stat [&lt;options&gt;] [&lt;command&gt;]

           -e, --event &lt;event&gt; event selector. use 'perf list' to list available events

  Event metrics:

   - Add "Compat" regex to match event with multiple identifiers.

   - Usual updates for Intel, Power10, Arm telemetry/CMN and AmpereOne.

  Misc:

   - Assorted memory leak fixes and footprint reduction.

   - Add "bpf_skeletons" to perf version --build-options so that users
     can check whether their perf tools have BPF support easily.

   - Fix unaligned access in Intel-PT packet decoder found by
     undefined-behavior sanitizer.

   - Avoid frequency mode for the dummy event. Surprisingly it'd impact
     kernel timer tick handler performance by force iterating all PMU
     events.

   - Update bash shell completion for events and metrics"

* tag 'perf-tools-for-v6.7-1-2023-11-01' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools: (187 commits)
  perf vendor events intel: Update tsx_cycles_per_elision metrics
  perf vendor events intel: Update bonnell version number to v5
  perf vendor events intel: Update westmereex events to v4
  perf vendor events intel: Update meteorlake events to v1.06
  perf vendor events intel: Update knightslanding events to v16
  perf vendor events intel: Add typo fix for ivybridge FP
  perf vendor events intel: Update a spelling in haswell/haswellx
  perf vendor events intel: Update emeraldrapids to v1.01
  perf vendor events intel: Update alderlake/alderlake events to v1.23
  perf build: Disable BPF skeletons if clang version is &lt; 12.0.1
  perf callchain: Fix spelling mistake "statisitcs" -&gt; "statistics"
  perf report: Fix spelling mistake "heirachy" -&gt; "hierarchy"
  perf python: Fix binding linkage due to rename and move of evsel__increase_rlimit()
  perf tests: test_arm_coresight: Simplify source iteration
  perf vendor events intel: Add tigerlake two metrics
  perf vendor events intel: Add broadwellde two metrics
  perf vendor events intel: Fix broadwellde tma_info_system_dram_bw_use metric
  perf mem_info: Add and use map_symbol__exit and addr_map_symbol__exit
  perf callchain: Minor layout changes to callchain_list
  perf callchain: Make brtype_stat in callchain_list optional
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>libperf rc_check: Add RC_CHK_EQUAL</title>
<updated>2023-10-25T20:37:22+00:00</updated>
<author>
<name>Ian Rogers</name>
<email>irogers@google.com</email>
</author>
<published>2023-10-24T22:23:07+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=78c32f4cb12f9430e29402118635dcf972b7d325'/>
<id>78c32f4cb12f9430e29402118635dcf972b7d325</id>
<content type='text'>
Comparing pointers with reference count checking is tricky to avoid a
SEGV. Add a convenience macro to simplify and use.

Signed-off-by: Ian Rogers &lt;irogers@google.com&gt;
Cc: K Prateek Nayak &lt;kprateek.nayak@amd.com&gt;
Cc: Ravi Bangoria &lt;ravi.bangoria@amd.com&gt;
Cc: Sandipan Das &lt;sandipan.das@amd.com&gt;
Cc: Anshuman Khandual &lt;anshuman.khandual@arm.com&gt;
Cc: German Gomez &lt;german.gomez@arm.com&gt;
Cc: James Clark &lt;james.clark@arm.com&gt;
Cc: Nick Terrell &lt;terrelln@fb.com&gt;
Cc: Sean Christopherson &lt;seanjc@google.com&gt;
Cc: Changbin Du &lt;changbin.du@huawei.com&gt;
Cc: liuwenyu &lt;liuwenyu7@huawei.com&gt;
Cc: Yang Jihong &lt;yangjihong1@huawei.com&gt;
Cc: Masami Hiramatsu &lt;mhiramat@kernel.org&gt;
Cc: Miguel Ojeda &lt;ojeda@kernel.org&gt;
Cc: Song Liu &lt;song@kernel.org&gt;
Cc: Leo Yan &lt;leo.yan@linaro.org&gt;
Cc: Kajol Jain &lt;kjain@linux.ibm.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Kan Liang &lt;kan.liang@linux.intel.com&gt;
Cc: Athira Rajeev &lt;atrajeev@linux.vnet.ibm.com&gt;
Cc: Yanteng Si &lt;siyanteng@loongson.cn&gt;
Cc: Liam Howlett &lt;liam.howlett@oracle.com&gt;
Cc: Paolo Bonzini &lt;pbonzini@redhat.com&gt;
Link: https://lore.kernel.org/r/20231024222353.3024098-5-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>
Comparing pointers with reference count checking is tricky to avoid a
SEGV. Add a convenience macro to simplify and use.

Signed-off-by: Ian Rogers &lt;irogers@google.com&gt;
Cc: K Prateek Nayak &lt;kprateek.nayak@amd.com&gt;
Cc: Ravi Bangoria &lt;ravi.bangoria@amd.com&gt;
Cc: Sandipan Das &lt;sandipan.das@amd.com&gt;
Cc: Anshuman Khandual &lt;anshuman.khandual@arm.com&gt;
Cc: German Gomez &lt;german.gomez@arm.com&gt;
Cc: James Clark &lt;james.clark@arm.com&gt;
Cc: Nick Terrell &lt;terrelln@fb.com&gt;
Cc: Sean Christopherson &lt;seanjc@google.com&gt;
Cc: Changbin Du &lt;changbin.du@huawei.com&gt;
Cc: liuwenyu &lt;liuwenyu7@huawei.com&gt;
Cc: Yang Jihong &lt;yangjihong1@huawei.com&gt;
Cc: Masami Hiramatsu &lt;mhiramat@kernel.org&gt;
Cc: Miguel Ojeda &lt;ojeda@kernel.org&gt;
Cc: Song Liu &lt;song@kernel.org&gt;
Cc: Leo Yan &lt;leo.yan@linaro.org&gt;
Cc: Kajol Jain &lt;kjain@linux.ibm.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Kan Liang &lt;kan.liang@linux.intel.com&gt;
Cc: Athira Rajeev &lt;atrajeev@linux.vnet.ibm.com&gt;
Cc: Yanteng Si &lt;siyanteng@loongson.cn&gt;
Cc: Liam Howlett &lt;liam.howlett@oracle.com&gt;
Cc: Paolo Bonzini &lt;pbonzini@redhat.com&gt;
Link: https://lore.kernel.org/r/20231024222353.3024098-5-irogers@google.com
Signed-off-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
