<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/tools/lib, branch v6.6.16</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>libsubcmd: Fix memory leak in uniq()</title>
<updated>2024-02-05T20:14:32+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=6757fd72312bb3488f902b4b03953da73ef3276c'/>
<id>6757fd72312bb3488f902b4b03953da73ef3276c</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>2024-02-05T20:14:24+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=5f3e436832e86b826a6450eb8d1aaa51205a758e'/>
<id>5f3e436832e86b826a6450eb8d1aaa51205a758e</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>2024-02-05T20:14:18+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=aec8c7b1334b5f28b49bccc84fcfbae06f4b3f20'/>
<id>aec8c7b1334b5f28b49bccc84fcfbae06f4b3f20</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>2024-01-25T23:35:51+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=e9b7b8b3ac2cb8abb30f181fcc8a8838f7bda121'/>
<id>e9b7b8b3ac2cb8abb30f181fcc8a8838f7bda121</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>libperf rc_check: Make implicit enabling work for GCC</title>
<updated>2023-11-20T10:59:29+00:00</updated>
<author>
<name>Ian Rogers</name>
<email>irogers@google.com</email>
</author>
<published>2023-10-24T22:23:06+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=082c59ce88d652e96f25bb18fb79e18f7db63449'/>
<id>082c59ce88d652e96f25bb18fb79e18f7db63449</id>
<content type='text'>
[ Upstream commit 75265320d290c5f5891f16967b94883676c46705 ]

Make the implicit REFCOUNT_CHECKING robust to when building with GCC.

Fixes: 9be6ab181b7b ("libperf rc_check: Enable implicitly with sanitizers")
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/20231024222353.3024098-4-irogers@google.com
Signed-off-by: Namhyung Kim &lt;namhyung@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 75265320d290c5f5891f16967b94883676c46705 ]

Make the implicit REFCOUNT_CHECKING robust to when building with GCC.

Fixes: 9be6ab181b7b ("libperf rc_check: Enable implicitly with sanitizers")
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/20231024222353.3024098-4-irogers@google.com
Signed-off-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>libbpf: Fix syscall access arguments on riscv</title>
<updated>2023-11-20T10:59:00+00:00</updated>
<author>
<name>Alexandre Ghiti</name>
<email>alexghiti@rivosinc.com</email>
</author>
<published>2023-10-04T11:09:03+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=af1f32c95bd8823d00c83de15f1a5552478624a9'/>
<id>af1f32c95bd8823d00c83de15f1a5552478624a9</id>
<content type='text'>
[ Upstream commit 8a412c5c1cd6cc6c55e8b9b84fbb789fc395fe78 ]

Since commit 08d0ce30e0e4 ("riscv: Implement syscall wrappers"), riscv
selects ARCH_HAS_SYSCALL_WRAPPER so let's use the generic implementation
of PT_REGS_SYSCALL_REGS().

Fixes: 08d0ce30e0e4 ("riscv: Implement syscall wrappers")
Signed-off-by: Alexandre Ghiti &lt;alexghiti@rivosinc.com&gt;
Signed-off-by: Andrii Nakryiko &lt;andrii@kernel.org&gt;
Reviewed-by: Sami Tolvanen &lt;samitolvanen@google.com&gt;
Link: https://lore.kernel.org/bpf/20231004110905.49024-2-bjorn@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 8a412c5c1cd6cc6c55e8b9b84fbb789fc395fe78 ]

Since commit 08d0ce30e0e4 ("riscv: Implement syscall wrappers"), riscv
selects ARCH_HAS_SYSCALL_WRAPPER so let's use the generic implementation
of PT_REGS_SYSCALL_REGS().

Fixes: 08d0ce30e0e4 ("riscv: Implement syscall wrappers")
Signed-off-by: Alexandre Ghiti &lt;alexghiti@rivosinc.com&gt;
Signed-off-by: Andrii Nakryiko &lt;andrii@kernel.org&gt;
Reviewed-by: Sami Tolvanen &lt;samitolvanen@google.com&gt;
Link: https://lore.kernel.org/bpf/20231004110905.49024-2-bjorn@kernel.org
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'perf-tools-for-v6.6-1-2023-09-05' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools</title>
<updated>2023-09-10T03:06:17+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2023-09-10T03:06:17+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=535a265d7f0dd50d8c3a4f8b4f3a452d56bd160f'/>
<id>535a265d7f0dd50d8c3a4f8b4f3a452d56bd160f</id>
<content type='text'>
Pull perf tools updates from Arnaldo Carvalho de Melo:
 "perf tools maintainership:

   - Add git information for perf-tools and perf-tools-next trees and
     branches to the MAINTAINERS file. That is where development now
     takes place and myself and Namhyung Kim have write access, more
     people to come as we emulate other maintainer groups.

  perf record:

   - Record kernel data maps when 'perf record --data' is used, so that
     global variables can be resolved and used in tools that do data
     profiling.

  perf trace:

   - Remove the old, experimental support for BPF events in which a .c
     file was passed as an event: "perf trace -e hello.c" to then get
     compiled and loaded.

     The only known usage for that, that shipped with the kernel as an
     example for such events, augmented the raw_syscalls tracepoints and
     was converted to a libbpf skeleton, reusing all the user space
     components and the BPF code connected to the syscalls.

     In the end just the way to glue the BPF part and the user space
     type beautifiers changed, now being performed by libbpf skeletons.

     The next step is to use BTF to do pretty printing of all syscall
     types, as discussed with Alan Maguire and others.

     Now, on a perf built with BUILD_BPF_SKEL=1 we get most if not all
     path/filenames/strings, some of the networking data structures,
     perf_event_attr, etc, i.e. systemwide tracing of nanosleep calls
     and perf_event_open syscalls while 'perf stat' runs 'sleep' for 5
     seconds:

      # perf trace -a -e *nanosleep,perf* perf stat -e cycles,instructions sleep 5
         0.000 (   9.034 ms): perf/327641 perf_event_open(attr_uptr: { type: 0 (PERF_TYPE_HARDWARE), size: 136, config: 0 (PERF_COUNT_HW_CPU_CYCLES), sample_type: IDENTIFIER, read_format: TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING, disabled: 1, inherit: 1, enable_on_exec: 1, exclude_guest: 1 }, pid: 327642 (perf), cpu: -1, group_fd: -1, flags: FD_CLOEXEC) = 3
         9.039 (   0.006 ms): perf/327641 perf_event_open(attr_uptr: { type: 0 (PERF_TYPE_HARDWARE), size: 136, config: 0x1 (PERF_COUNT_HW_INSTRUCTIONS), sample_type: IDENTIFIER, read_format: TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING, disabled: 1, inherit: 1, enable_on_exec: 1, exclude_guest: 1 }, pid: 327642 (perf-exec), cpu: -1, group_fd: -1, flags: FD_CLOEXEC) = 4
             ? (           ): gpm/991  ... [continued]: clock_nanosleep())               = 0
        10.133 (           ): sleep/327642 clock_nanosleep(rqtp: { .tv_sec: 5, .tv_nsec: 0 }, rmtp: 0x7ffd36f83ed0) ...
             ? (           ): pool-gsd-smart/3051  ... [continued]: clock_nanosleep())   = 0
        30.276 (           ): gpm/991 clock_nanosleep(rqtp: { .tv_sec: 2, .tv_nsec: 0 }, rmtp: 0x7ffcc6f73710) ...
       223.215 (1000.430 ms): pool-gsd-smart/3051 clock_nanosleep(rqtp: { .tv_sec: 1, .tv_nsec: 0 }, rmtp: 0x7f6e7fffec90) = 0
        30.276 (2000.394 ms): gpm/991  ... [continued]: clock_nanosleep())               = 0
      1230.814 (           ): pool-gsd-smart/3051 clock_nanosleep(rqtp: { .tv_sec: 1, .tv_nsec: 0 }, rmtp: 0x7f6e7fffec90) ...
      1230.814 (1000.404 ms): pool-gsd-smart/3051  ... [continued]: clock_nanosleep())   = 0
      2030.886 (           ): gpm/991 clock_nanosleep(rqtp: { .tv_sec: 2, .tv_nsec: 0 }, rmtp: 0x7ffcc6f73710) ...
      2237.709 (1000.153 ms): pool-gsd-smart/3051 clock_nanosleep(rqtp: { .tv_sec: 1, .tv_nsec: 0 }, rmtp: 0x7f6e7fffec90) = 0
             ? (           ): crond/1172  ... [continued]: clock_nanosleep())            = 0
      3242.699 (           ): pool-gsd-smart/3051 clock_nanosleep(rqtp: { .tv_sec: 1, .tv_nsec: 0 }, rmtp: 0x7f6e7fffec90) ...
      2030.886 (2000.385 ms): gpm/991  ... [continued]: clock_nanosleep())               = 0
      3728.078 (           ): crond/1172 clock_nanosleep(rqtp: { .tv_sec: 60, .tv_nsec: 0 }, rmtp: 0x7ffe0971dcf0) ...
      3242.699 (1000.158 ms): pool-gsd-smart/3051  ... [continued]: clock_nanosleep())   = 0
      4031.409 (           ): gpm/991 clock_nanosleep(rqtp: { .tv_sec: 2, .tv_nsec: 0 }, rmtp: 0x7ffcc6f73710) ...
        10.133 (5000.375 ms): sleep/327642  ... [continued]: clock_nanosleep())          = 0

      Performance counter stats for 'sleep 5':

             2,617,347      cycles
             1,855,997      instructions                     #    0.71  insn per cycle

           5.002282128 seconds time elapsed

           0.000855000 seconds user
           0.000852000 seconds sys

  perf annotate:

   - Building with binutils' libopcode now is opt-in (BUILD_NONDISTRO=1)
     for licensing reasons, and we missed a build test on
     tools/perf/tests makefile.

     Since we now default to NDEBUG=1, we ended up segfaulting when
     building with BUILD_NONDISTRO=1 because a needed initialization
     routine was being "error checked" via an assert.

     Fix it by explicitly checking the result and aborting instead if it
     fails.

     We better back propagate the error, but at least 'perf annotate' on
     samples collected for a BPF program is back working when perf is
     built with BUILD_NONDISTRO=1.

  perf report/top:

   - Add back TUI hierarchy mode header, that is seen when using 'perf
     report/top --hierarchy'.

   - Fix the number of entries for 'e' key in the TUI that was
     preventing navigation of lines when expanding an entry.

  perf report/script:

   - Support cross platform register handling, allowing a perf.data file
     collected on one architecture to have registers sampled correctly
     displayed when analysis tools such as 'perf report' and 'perf
     script' are used on a different architecture.

   - Fix handling of event attributes in pipe mode, i.e. when one uses:

  	perf record -o - | perf report -i -

     When no perf.data files are used.

   - Handle files generated via pipe mode with a version of perf and
     then read also via pipe mode with a different version of perf,
     where the event attr record may have changed, use the record size
     field to properly support this version mismatch.

  perf probe:

   - Accessing global variables from uprobes isn't supported, make the
     error message state that instead of stating that some minimal
     kernel version is needed to have that feature. This seems just a
     tool limitation, the kernel probably has all that is needed.

  perf tests:

   - Fix a reference count related leak in the dlfilter v0 API where the
     result of a thread__find_symbol_fb() is not matched with an
     addr_location__exit() to drop the reference counts of the resolved
     components (machine, thread, map, symbol, etc). Add a dlfilter test
     to make sure that doesn't regresses.

   - Lots of fixes for the 'perf test' written in shell script related
     to problems found with the shellcheck utility.

   - Fixes for 'perf test' shell scripts testing features enabled when
     perf is built with BUILD_BPF_SKEL=1, such as 'perf stat' bpf
     counters.

   - Add perf record sample filtering test, things like the following
     example, that gets implemented as a BPF filter attached to the
     event:

       # perf record -e task-clock -c 10000 --filter 'ip &lt; 0xffffffff00000000'

   - Improve the way the task_analyzer test checks if libtraceevent is
     linked, using 'perf version --build-options' instead of the more
     expensinve 'perf record -e "sched:sched_switch"'.

   - Add support for riscv in the mmap-basic test. (This went as well
     via the RiscV tree, same contents).

  libperf:

   - Implement riscv mmap support (This went as well via the RiscV tree,
     same contents).

  perf script:

   - New tool that converts perf.data files to the firefox profiler
     format so that one can use the visualizer at
     https://profiler.firefox.com/. Done by Anup Sharma as part of this
     year's Google Summer of Code.

     One can generate the output and upload it to the web interface but
     Anup also automated everything:

       perf script gecko -F 99 -a sleep 60

   - Support syscall name parsing on arm64.

   - Print "cgroup" field on the same line as "comm".

  perf bench:

   - Add new 'uprobe' benchmark to measure the overhead of uprobes
     with/without BPF programs attached to it.

   - breakpoints are not available on power9, skip that test.

  perf stat:

   - Add #num_cpus_online literal to be used in 'perf stat' metrics, and
     add this extra 'perf test' check that exemplifies its purpose:

  	TEST_ASSERT_VAL("#num_cpus_online",
                         expr__parse(&amp;num_cpus_online, ctx, "#num_cpus_online") == 0);
  	TEST_ASSERT_VAL("#num_cpus", expr__parse(&amp;num_cpus, ctx, "#num_cpus") == 0);
  	TEST_ASSERT_VAL("#num_cpus &gt;= #num_cpus_online", num_cpus &gt;= num_cpus_online);

  Miscellaneous:

   - Improve tool startup time by lazily reading PMU, JSON, sysfs data.

   - Improve error reporting in the parsing of events, passing YYLTYPE
     to error routines, so that the output can show were the parsing
     error was found.

   - Add 'perf test' entries to check the parsing of events
     improvements.

   - Fix various leak for things detected by -fsanitize=address, mostly
     things that would be freed at tool exit, including:

       - Free evsel-&gt;filter on the destructor.

       - Allow tools to register a thread-&gt;priv destructor and use it in
         'perf trace'.

       - Free evsel-&gt;priv in 'perf trace'.

       - Free string returned by synthesize_perf_probe_point() when the
         caller fails to do all it needs.

   - Adjust various compiler options to not consider errors some
     warnings when building with broken headers found in things like
     python, flex, bison, as we otherwise build with -Werror. Some for
     gcc, some for clang, some for some specific version of those, some
     for some specific version of flex or bison, or some specific
     combination of these components, bah.

   - Allow customization of clang options for BPF target, this helps
     building on gentoo where there are other oddities where BPF targets
     gets passed some compiler options intended for the native build, so
     building with WERROR=0 helps while these oddities are fixed.

   - Dont pass ERR_PTR() values to perf_session__delete() in 'perf top'
     and 'perf lock', fixing some segfaults when handling some odd
     failures.

   - Add LTO build option.

   - Fix format of unordered lists in the perf docs
     (tools/perf/Documentation)

   - Overhaul the bison files, using constructs such as YYNOMEM.

   - Remove unused tokens from the bison .y files.

   - Add more comments to various structs.

   - A few LoongArch enablement patches.

  Vendor events (JSON):

   - Add JSON metrics for Yitian 710 DDR (aarch64). Things like:

  	EventName, BriefDescription
  	visible_window_limit_reached_rd, "At least one entry in read queue reaches the visible window limit.",
  	visible_window_limit_reached_wr, "At least one entry in write queue reaches the visible window limit.",
  	op_is_dqsosc_mpc	       , "A DQS Oscillator MPC command to DRAM.",
  	op_is_dqsosc_mrr	       , "A DQS Oscillator MRR command to DRAM.",
  	op_is_tcr_mrr		       , "A Temperature Compensated Refresh(TCR) MRR command to DRAM.",

   - Add AmpereOne metrics (aarch64).

   - Update N2 and V2 metrics (aarch64) and events using Arm telemetry
     repo.

   - Update scale units and descriptions of common topdown metrics on
     aarch64. Things like:
       - "MetricExpr": "stall_slot_frontend / (#slots * cpu_cycles)",
       - "BriefDescription": "Frontend bound L1 topdown metric",
       + "MetricExpr": "100 * (stall_slot_frontend / (#slots * cpu_cycles))",
       + "BriefDescription": "This metric is the percentage of total slots that were stalled due to resource constraints in the frontend of the processor.",

   - Update events for intel: meteorlake to 1.04, sapphirerapids to
     1.15, Icelake+ metric constraints.

   - Update files for the power10 platform"

* tag 'perf-tools-for-v6.6-1-2023-09-05' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools: (217 commits)
  perf parse-events: Fix driver config term
  perf parse-events: Fixes relating to no_value terms
  perf parse-events: Fix propagation of term's no_value when cloning
  perf parse-events: Name the two term enums
  perf list: Don't print Unit for "default_core"
  perf vendor events intel: Fix modifier in tma_info_system_mem_parallel_reads for skylake
  perf dlfilter: Avoid leak in v0 API test use of resolve_address()
  perf metric: Add #num_cpus_online literal
  perf pmu: Remove str from perf_pmu_alias
  perf parse-events: Make common term list to strbuf helper
  perf parse-events: Minor help message improvements
  perf pmu: Avoid uninitialized use of alias-&gt;str
  perf jevents: Use "default_core" for events with no Unit
  perf test stat_bpf_counters_cgrp: Enhance perf stat cgroup BPF counter test
  perf test shell stat_bpf_counters: Fix test on Intel
  perf test shell record_bpf_filter: Skip 6.2 kernel
  libperf: Get rid of attr.id field
  perf tools: Convert to perf_record_header_attr_id()
  libperf: Add perf_record_header_attr_id()
  perf tools: Handle old data in PERF_RECORD_ATTR
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull perf tools updates from Arnaldo Carvalho de Melo:
 "perf tools maintainership:

   - Add git information for perf-tools and perf-tools-next trees and
     branches to the MAINTAINERS file. That is where development now
     takes place and myself and Namhyung Kim have write access, more
     people to come as we emulate other maintainer groups.

  perf record:

   - Record kernel data maps when 'perf record --data' is used, so that
     global variables can be resolved and used in tools that do data
     profiling.

  perf trace:

   - Remove the old, experimental support for BPF events in which a .c
     file was passed as an event: "perf trace -e hello.c" to then get
     compiled and loaded.

     The only known usage for that, that shipped with the kernel as an
     example for such events, augmented the raw_syscalls tracepoints and
     was converted to a libbpf skeleton, reusing all the user space
     components and the BPF code connected to the syscalls.

     In the end just the way to glue the BPF part and the user space
     type beautifiers changed, now being performed by libbpf skeletons.

     The next step is to use BTF to do pretty printing of all syscall
     types, as discussed with Alan Maguire and others.

     Now, on a perf built with BUILD_BPF_SKEL=1 we get most if not all
     path/filenames/strings, some of the networking data structures,
     perf_event_attr, etc, i.e. systemwide tracing of nanosleep calls
     and perf_event_open syscalls while 'perf stat' runs 'sleep' for 5
     seconds:

      # perf trace -a -e *nanosleep,perf* perf stat -e cycles,instructions sleep 5
         0.000 (   9.034 ms): perf/327641 perf_event_open(attr_uptr: { type: 0 (PERF_TYPE_HARDWARE), size: 136, config: 0 (PERF_COUNT_HW_CPU_CYCLES), sample_type: IDENTIFIER, read_format: TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING, disabled: 1, inherit: 1, enable_on_exec: 1, exclude_guest: 1 }, pid: 327642 (perf), cpu: -1, group_fd: -1, flags: FD_CLOEXEC) = 3
         9.039 (   0.006 ms): perf/327641 perf_event_open(attr_uptr: { type: 0 (PERF_TYPE_HARDWARE), size: 136, config: 0x1 (PERF_COUNT_HW_INSTRUCTIONS), sample_type: IDENTIFIER, read_format: TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING, disabled: 1, inherit: 1, enable_on_exec: 1, exclude_guest: 1 }, pid: 327642 (perf-exec), cpu: -1, group_fd: -1, flags: FD_CLOEXEC) = 4
             ? (           ): gpm/991  ... [continued]: clock_nanosleep())               = 0
        10.133 (           ): sleep/327642 clock_nanosleep(rqtp: { .tv_sec: 5, .tv_nsec: 0 }, rmtp: 0x7ffd36f83ed0) ...
             ? (           ): pool-gsd-smart/3051  ... [continued]: clock_nanosleep())   = 0
        30.276 (           ): gpm/991 clock_nanosleep(rqtp: { .tv_sec: 2, .tv_nsec: 0 }, rmtp: 0x7ffcc6f73710) ...
       223.215 (1000.430 ms): pool-gsd-smart/3051 clock_nanosleep(rqtp: { .tv_sec: 1, .tv_nsec: 0 }, rmtp: 0x7f6e7fffec90) = 0
        30.276 (2000.394 ms): gpm/991  ... [continued]: clock_nanosleep())               = 0
      1230.814 (           ): pool-gsd-smart/3051 clock_nanosleep(rqtp: { .tv_sec: 1, .tv_nsec: 0 }, rmtp: 0x7f6e7fffec90) ...
      1230.814 (1000.404 ms): pool-gsd-smart/3051  ... [continued]: clock_nanosleep())   = 0
      2030.886 (           ): gpm/991 clock_nanosleep(rqtp: { .tv_sec: 2, .tv_nsec: 0 }, rmtp: 0x7ffcc6f73710) ...
      2237.709 (1000.153 ms): pool-gsd-smart/3051 clock_nanosleep(rqtp: { .tv_sec: 1, .tv_nsec: 0 }, rmtp: 0x7f6e7fffec90) = 0
             ? (           ): crond/1172  ... [continued]: clock_nanosleep())            = 0
      3242.699 (           ): pool-gsd-smart/3051 clock_nanosleep(rqtp: { .tv_sec: 1, .tv_nsec: 0 }, rmtp: 0x7f6e7fffec90) ...
      2030.886 (2000.385 ms): gpm/991  ... [continued]: clock_nanosleep())               = 0
      3728.078 (           ): crond/1172 clock_nanosleep(rqtp: { .tv_sec: 60, .tv_nsec: 0 }, rmtp: 0x7ffe0971dcf0) ...
      3242.699 (1000.158 ms): pool-gsd-smart/3051  ... [continued]: clock_nanosleep())   = 0
      4031.409 (           ): gpm/991 clock_nanosleep(rqtp: { .tv_sec: 2, .tv_nsec: 0 }, rmtp: 0x7ffcc6f73710) ...
        10.133 (5000.375 ms): sleep/327642  ... [continued]: clock_nanosleep())          = 0

      Performance counter stats for 'sleep 5':

             2,617,347      cycles
             1,855,997      instructions                     #    0.71  insn per cycle

           5.002282128 seconds time elapsed

           0.000855000 seconds user
           0.000852000 seconds sys

  perf annotate:

   - Building with binutils' libopcode now is opt-in (BUILD_NONDISTRO=1)
     for licensing reasons, and we missed a build test on
     tools/perf/tests makefile.

     Since we now default to NDEBUG=1, we ended up segfaulting when
     building with BUILD_NONDISTRO=1 because a needed initialization
     routine was being "error checked" via an assert.

     Fix it by explicitly checking the result and aborting instead if it
     fails.

     We better back propagate the error, but at least 'perf annotate' on
     samples collected for a BPF program is back working when perf is
     built with BUILD_NONDISTRO=1.

  perf report/top:

   - Add back TUI hierarchy mode header, that is seen when using 'perf
     report/top --hierarchy'.

   - Fix the number of entries for 'e' key in the TUI that was
     preventing navigation of lines when expanding an entry.

  perf report/script:

   - Support cross platform register handling, allowing a perf.data file
     collected on one architecture to have registers sampled correctly
     displayed when analysis tools such as 'perf report' and 'perf
     script' are used on a different architecture.

   - Fix handling of event attributes in pipe mode, i.e. when one uses:

  	perf record -o - | perf report -i -

     When no perf.data files are used.

   - Handle files generated via pipe mode with a version of perf and
     then read also via pipe mode with a different version of perf,
     where the event attr record may have changed, use the record size
     field to properly support this version mismatch.

  perf probe:

   - Accessing global variables from uprobes isn't supported, make the
     error message state that instead of stating that some minimal
     kernel version is needed to have that feature. This seems just a
     tool limitation, the kernel probably has all that is needed.

  perf tests:

   - Fix a reference count related leak in the dlfilter v0 API where the
     result of a thread__find_symbol_fb() is not matched with an
     addr_location__exit() to drop the reference counts of the resolved
     components (machine, thread, map, symbol, etc). Add a dlfilter test
     to make sure that doesn't regresses.

   - Lots of fixes for the 'perf test' written in shell script related
     to problems found with the shellcheck utility.

   - Fixes for 'perf test' shell scripts testing features enabled when
     perf is built with BUILD_BPF_SKEL=1, such as 'perf stat' bpf
     counters.

   - Add perf record sample filtering test, things like the following
     example, that gets implemented as a BPF filter attached to the
     event:

       # perf record -e task-clock -c 10000 --filter 'ip &lt; 0xffffffff00000000'

   - Improve the way the task_analyzer test checks if libtraceevent is
     linked, using 'perf version --build-options' instead of the more
     expensinve 'perf record -e "sched:sched_switch"'.

   - Add support for riscv in the mmap-basic test. (This went as well
     via the RiscV tree, same contents).

  libperf:

   - Implement riscv mmap support (This went as well via the RiscV tree,
     same contents).

  perf script:

   - New tool that converts perf.data files to the firefox profiler
     format so that one can use the visualizer at
     https://profiler.firefox.com/. Done by Anup Sharma as part of this
     year's Google Summer of Code.

     One can generate the output and upload it to the web interface but
     Anup also automated everything:

       perf script gecko -F 99 -a sleep 60

   - Support syscall name parsing on arm64.

   - Print "cgroup" field on the same line as "comm".

  perf bench:

   - Add new 'uprobe' benchmark to measure the overhead of uprobes
     with/without BPF programs attached to it.

   - breakpoints are not available on power9, skip that test.

  perf stat:

   - Add #num_cpus_online literal to be used in 'perf stat' metrics, and
     add this extra 'perf test' check that exemplifies its purpose:

  	TEST_ASSERT_VAL("#num_cpus_online",
                         expr__parse(&amp;num_cpus_online, ctx, "#num_cpus_online") == 0);
  	TEST_ASSERT_VAL("#num_cpus", expr__parse(&amp;num_cpus, ctx, "#num_cpus") == 0);
  	TEST_ASSERT_VAL("#num_cpus &gt;= #num_cpus_online", num_cpus &gt;= num_cpus_online);

  Miscellaneous:

   - Improve tool startup time by lazily reading PMU, JSON, sysfs data.

   - Improve error reporting in the parsing of events, passing YYLTYPE
     to error routines, so that the output can show were the parsing
     error was found.

   - Add 'perf test' entries to check the parsing of events
     improvements.

   - Fix various leak for things detected by -fsanitize=address, mostly
     things that would be freed at tool exit, including:

       - Free evsel-&gt;filter on the destructor.

       - Allow tools to register a thread-&gt;priv destructor and use it in
         'perf trace'.

       - Free evsel-&gt;priv in 'perf trace'.

       - Free string returned by synthesize_perf_probe_point() when the
         caller fails to do all it needs.

   - Adjust various compiler options to not consider errors some
     warnings when building with broken headers found in things like
     python, flex, bison, as we otherwise build with -Werror. Some for
     gcc, some for clang, some for some specific version of those, some
     for some specific version of flex or bison, or some specific
     combination of these components, bah.

   - Allow customization of clang options for BPF target, this helps
     building on gentoo where there are other oddities where BPF targets
     gets passed some compiler options intended for the native build, so
     building with WERROR=0 helps while these oddities are fixed.

   - Dont pass ERR_PTR() values to perf_session__delete() in 'perf top'
     and 'perf lock', fixing some segfaults when handling some odd
     failures.

   - Add LTO build option.

   - Fix format of unordered lists in the perf docs
     (tools/perf/Documentation)

   - Overhaul the bison files, using constructs such as YYNOMEM.

   - Remove unused tokens from the bison .y files.

   - Add more comments to various structs.

   - A few LoongArch enablement patches.

  Vendor events (JSON):

   - Add JSON metrics for Yitian 710 DDR (aarch64). Things like:

  	EventName, BriefDescription
  	visible_window_limit_reached_rd, "At least one entry in read queue reaches the visible window limit.",
  	visible_window_limit_reached_wr, "At least one entry in write queue reaches the visible window limit.",
  	op_is_dqsosc_mpc	       , "A DQS Oscillator MPC command to DRAM.",
  	op_is_dqsosc_mrr	       , "A DQS Oscillator MRR command to DRAM.",
  	op_is_tcr_mrr		       , "A Temperature Compensated Refresh(TCR) MRR command to DRAM.",

   - Add AmpereOne metrics (aarch64).

   - Update N2 and V2 metrics (aarch64) and events using Arm telemetry
     repo.

   - Update scale units and descriptions of common topdown metrics on
     aarch64. Things like:
       - "MetricExpr": "stall_slot_frontend / (#slots * cpu_cycles)",
       - "BriefDescription": "Frontend bound L1 topdown metric",
       + "MetricExpr": "100 * (stall_slot_frontend / (#slots * cpu_cycles))",
       + "BriefDescription": "This metric is the percentage of total slots that were stalled due to resource constraints in the frontend of the processor.",

   - Update events for intel: meteorlake to 1.04, sapphirerapids to
     1.15, Icelake+ metric constraints.

   - Update files for the power10 platform"

* tag 'perf-tools-for-v6.6-1-2023-09-05' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools: (217 commits)
  perf parse-events: Fix driver config term
  perf parse-events: Fixes relating to no_value terms
  perf parse-events: Fix propagation of term's no_value when cloning
  perf parse-events: Name the two term enums
  perf list: Don't print Unit for "default_core"
  perf vendor events intel: Fix modifier in tma_info_system_mem_parallel_reads for skylake
  perf dlfilter: Avoid leak in v0 API test use of resolve_address()
  perf metric: Add #num_cpus_online literal
  perf pmu: Remove str from perf_pmu_alias
  perf parse-events: Make common term list to strbuf helper
  perf parse-events: Minor help message improvements
  perf pmu: Avoid uninitialized use of alias-&gt;str
  perf jevents: Use "default_core" for events with no Unit
  perf test stat_bpf_counters_cgrp: Enhance perf stat cgroup BPF counter test
  perf test shell stat_bpf_counters: Fix test on Intel
  perf test shell record_bpf_filter: Skip 6.2 kernel
  libperf: Get rid of attr.id field
  perf tools: Convert to perf_record_header_attr_id()
  libperf: Add perf_record_header_attr_id()
  perf tools: Handle old data in PERF_RECORD_ATTR
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'riscv-for-linus-6.6-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux</title>
<updated>2023-09-01T15:09:48+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2023-09-01T15:09:48+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=e0152e7481c6c63764d6ea8ee41af5cf9dfac5e9'/>
<id>e0152e7481c6c63764d6ea8ee41af5cf9dfac5e9</id>
<content type='text'>
Pull RISC-V updates from Palmer Dabbelt:

 - Support for the new "riscv,isa-extensions" and "riscv,isa-base"
   device tree interfaces for probing extensions

 - Support for userspace access to the performance counters

 - Support for more instructions in kprobes

 - Crash kernels can be allocated above 4GiB

 - Support for KCFI

 - Support for ELFs in !MMU configurations

 - ARCH_KMALLOC_MINALIGN has been reduced to 8

 - mmap() defaults to sv48-sized addresses, with longer addresses hidden
   behind a hint (similar to Arm and Intel)

 - Also various fixes and cleanups

* tag 'riscv-for-linus-6.6-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (51 commits)
  lib/Kconfig.debug: Restrict DEBUG_INFO_SPLIT for RISC-V
  riscv: support PREEMPT_DYNAMIC with static keys
  riscv: Move create_tmp_mapping() to init sections
  riscv: Mark KASAN tmp* page tables variables as static
  riscv: mm: use bitmap_zero() API
  riscv: enable DEBUG_FORCE_FUNCTION_ALIGN_64B
  riscv: remove redundant mv instructions
  RISC-V: mm: Document mmap changes
  RISC-V: mm: Update pgtable comment documentation
  RISC-V: mm: Add tests for RISC-V mm
  RISC-V: mm: Restrict address space for sv39,sv48,sv57
  riscv: enable DMA_BOUNCE_UNALIGNED_KMALLOC for !dma_coherent
  riscv: allow kmalloc() caches aligned to the smallest value
  riscv: support the elf-fdpic binfmt loader
  binfmt_elf_fdpic: support 64-bit systems
  riscv: Allow CONFIG_CFI_CLANG to be selected
  riscv/purgatory: Disable CFI
  riscv: Add CFI error handling
  riscv: Add ftrace_stub_graph
  riscv: Add types to indirectly called assembly functions
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull RISC-V updates from Palmer Dabbelt:

 - Support for the new "riscv,isa-extensions" and "riscv,isa-base"
   device tree interfaces for probing extensions

 - Support for userspace access to the performance counters

 - Support for more instructions in kprobes

 - Crash kernels can be allocated above 4GiB

 - Support for KCFI

 - Support for ELFs in !MMU configurations

 - ARCH_KMALLOC_MINALIGN has been reduced to 8

 - mmap() defaults to sv48-sized addresses, with longer addresses hidden
   behind a hint (similar to Arm and Intel)

 - Also various fixes and cleanups

* tag 'riscv-for-linus-6.6-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (51 commits)
  lib/Kconfig.debug: Restrict DEBUG_INFO_SPLIT for RISC-V
  riscv: support PREEMPT_DYNAMIC with static keys
  riscv: Move create_tmp_mapping() to init sections
  riscv: Mark KASAN tmp* page tables variables as static
  riscv: mm: use bitmap_zero() API
  riscv: enable DEBUG_FORCE_FUNCTION_ALIGN_64B
  riscv: remove redundant mv instructions
  RISC-V: mm: Document mmap changes
  RISC-V: mm: Update pgtable comment documentation
  RISC-V: mm: Add tests for RISC-V mm
  RISC-V: mm: Restrict address space for sv39,sv48,sv57
  riscv: enable DMA_BOUNCE_UNALIGNED_KMALLOC for !dma_coherent
  riscv: allow kmalloc() caches aligned to the smallest value
  riscv: support the elf-fdpic binfmt loader
  binfmt_elf_fdpic: support 64-bit systems
  riscv: Allow CONFIG_CFI_CLANG to be selected
  riscv/purgatory: Disable CFI
  riscv: Add CFI error handling
  riscv: Add ftrace_stub_graph
  riscv: Add types to indirectly called assembly functions
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>libperf: Get rid of attr.id field</title>
<updated>2023-08-29T17:16:14+00:00</updated>
<author>
<name>Namhyung Kim</name>
<email>namhyung@kernel.org</email>
</author>
<published>2023-08-25T15:25:52+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=c091c78b73c82f1e2811ab19b8e287ddc7807651'/>
<id>c091c78b73c82f1e2811ab19b8e287ddc7807651</id>
<content type='text'>
Now there's no in-tree user of the field.  To remove the possible bug
later, let's get rid of the 'id' field and add a comment for that.

Signed-off-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Ian Rogers &lt;irogers@google.com&gt;
Cc: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Link: https://lore.kernel.org/r/20230825152552.112913-4-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Now there's no in-tree user of the field.  To remove the possible bug
later, let's get rid of the 'id' field and add a comment for that.

Signed-off-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Ian Rogers &lt;irogers@google.com&gt;
Cc: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Link: https://lore.kernel.org/r/20230825152552.112913-4-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>libperf: Add perf_record_header_attr_id()</title>
<updated>2023-08-29T17:16:14+00:00</updated>
<author>
<name>Namhyung Kim</name>
<email