<feed xmlns='http://www.w3.org/2005/Atom'>
<title>kernel/linux.git/tools/perf/util/machine.c, branch v5.15.209</title>
<subtitle>Linux kernel stable tree (mirror)</subtitle>
<id>https://git.radix-linux.su/kernel/linux.git/atom?h=v5.15.209</id>
<link rel='self' href='https://git.radix-linux.su/kernel/linux.git/atom?h=v5.15.209'/>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/'/>
<updated>2023-11-20T10:08:26+00:00</updated>
<entry>
<title>perf machine: Avoid out of bounds LBR memory read</title>
<updated>2023-11-20T10:08:26+00:00</updated>
<author>
<name>Ian Rogers</name>
<email>irogers@google.com</email>
</author>
<published>2023-10-24T22:23:05+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=924e8d0b7645a53f72b8e94a897861086df06e09'/>
<id>urn:sha1:924e8d0b7645a53f72b8e94a897861086df06e09</id>
<content type='text'>
[ Upstream commit ab8ce150781d326c6bfbe1e09f175ffde1186f80 ]

Running perf top with address sanitizer and "--call-graph=lbr" fails
due to reading sample 0 when no samples exist. Add a guard to prevent
this.

Fixes: e2b23483eb1d ("perf machine: Factor out lbr_callchain_add_lbr_ip()")
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/20231024222353.3024098-3-irogers@google.com
Signed-off-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
<entry>
<title>perf machine: Use path__join() to compose a path instead of snprintf(dir, '/', filename)</title>
<updated>2022-09-15T09:30:08+00:00</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
<email>acme@redhat.com</email>
</author>
<published>2022-01-18T12:02:43+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=154e72a4b38166b0b28d1f1a8d256ad5ca9ad064'/>
<id>urn:sha1:154e72a4b38166b0b28d1f1a8d256ad5ca9ad064</id>
<content type='text'>
commit 9d5f0c36438eeae7566ca383b2b673179e3cc613 upstream.

Its more intention revealing, and if we're interested in the odd cases
where this may end up truncating we can do debug checks at one
centralized place.

Motivation, of all the container builds, fedora rawhide started
complaining of:

  util/machine.c: In function ‘machine__create_modules’:
  util/machine.c:1419:50: error: ‘%s’ directive output may be truncated writing up to 255 bytes into a region of size between 0 and 4095 [-Werror=format-truncation=]
   1419 |                 snprintf(path, sizeof(path), "%s/%s", dir_name, dent-&gt;d_name);
        |                                                  ^~
  In file included from /usr/include/stdio.h:894,
                   from util/branch.h:9,
                   from util/callchain.h:8,
                   from util/machine.c:7:
  In function ‘snprintf’,
      inlined from ‘maps__set_modules_path_dir’ at util/machine.c:1419:3,
      inlined from ‘machine__set_modules_path’ at util/machine.c:1473:9,
      inlined from ‘machine__create_modules’ at util/machine.c:1519:7:
  /usr/include/bits/stdio2.h:71:10: note: ‘__builtin___snprintf_chk’ output between 2 and 4352 bytes into a destination of size 4096

There are other places where we should use path__join(), but lets get rid of
this one first.

Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Ian Rogers &lt;irogers@google.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Acked-by: Ian Rogers &lt;irogers@google.com&gt;
Link: Link: https://lore.kernel.org/r/YebZKjwgfdOz0lAs@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Signed-off-by: Jisheng Zhang &lt;jszhang@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>perf machine: Initialize srcline string member in add_location struct</title>
<updated>2021-09-18T20:43:05+00:00</updated>
<author>
<name>Michael Petlan</name>
<email>mpetlan@redhat.com</email>
</author>
<published>2021-07-19T14:53:32+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=57f0ff059e3daa4e70a811cb1d31a49968262d20'/>
<id>urn:sha1:57f0ff059e3daa4e70a811cb1d31a49968262d20</id>
<content type='text'>
It's later supposed to be either a correct address or NULL. Without the
initialization, it may contain an undefined value which results in the
following segmentation fault:

  # perf top --sort comm -g --ignore-callees=do_idle

terminates with:

  #0  0x00007ffff56b7685 in __strlen_avx2 () from /lib64/libc.so.6
  #1  0x00007ffff55e3802 in strdup () from /lib64/libc.so.6
  #2  0x00005555558cb139 in hist_entry__init (callchain_size=&lt;optimized out&gt;, sample_self=true, template=0x7fffde7fb110, he=0x7fffd801c250) at util/hist.c:489
  #3  hist_entry__new (template=template@entry=0x7fffde7fb110, sample_self=sample_self@entry=true) at util/hist.c:564
  #4  0x00005555558cb4ba in hists__findnew_entry (hists=hists@entry=0x5555561d9e38, entry=entry@entry=0x7fffde7fb110, al=al@entry=0x7fffde7fb420,
      sample_self=sample_self@entry=true) at util/hist.c:657
  #5  0x00005555558cba1b in __hists__add_entry (hists=hists@entry=0x5555561d9e38, al=0x7fffde7fb420, sym_parent=&lt;optimized out&gt;, bi=bi@entry=0x0, mi=mi@entry=0x0,
      sample=sample@entry=0x7fffde7fb4b0, sample_self=true, ops=0x0, block_info=0x0) at util/hist.c:288
  #6  0x00005555558cbb70 in hists__add_entry (sample_self=true, sample=0x7fffde7fb4b0, mi=0x0, bi=0x0, sym_parent=&lt;optimized out&gt;, al=&lt;optimized out&gt;, hists=0x5555561d9e38)
      at util/hist.c:1056
  #7  iter_add_single_cumulative_entry (iter=0x7fffde7fb460, al=&lt;optimized out&gt;) at util/hist.c:1056
  #8  0x00005555558cc8a4 in hist_entry_iter__add (iter=iter@entry=0x7fffde7fb460, al=al@entry=0x7fffde7fb420, max_stack_depth=&lt;optimized out&gt;, arg=arg@entry=0x7fffffff7db0)
      at util/hist.c:1231
  #9  0x00005555557cdc9a in perf_event__process_sample (machine=&lt;optimized out&gt;, sample=0x7fffde7fb4b0, evsel=&lt;optimized out&gt;, event=&lt;optimized out&gt;, tool=0x7fffffff7db0)
      at builtin-top.c:842
  #10 deliver_event (qe=&lt;optimized out&gt;, qevent=&lt;optimized out&gt;) at builtin-top.c:1202
  #11 0x00005555558a9318 in do_flush (show_progress=false, oe=0x7fffffff80e0) at util/ordered-events.c:244
  #12 __ordered_events__flush (oe=oe@entry=0x7fffffff80e0, how=how@entry=OE_FLUSH__TOP, timestamp=timestamp@entry=0) at util/ordered-events.c:323
  #13 0x00005555558a9789 in __ordered_events__flush (timestamp=&lt;optimized out&gt;, how=&lt;optimized out&gt;, oe=&lt;optimized out&gt;) at util/ordered-events.c:339
  #14 ordered_events__flush (how=OE_FLUSH__TOP, oe=0x7fffffff80e0) at util/ordered-events.c:341
  #15 ordered_events__flush (oe=oe@entry=0x7fffffff80e0, how=how@entry=OE_FLUSH__TOP) at util/ordered-events.c:339
  #16 0x00005555557cd631 in process_thread (arg=0x7fffffff7db0) at builtin-top.c:1114
  #17 0x00007ffff7bb817a in start_thread () from /lib64/libpthread.so.0
  #18 0x00007ffff5656dc3 in clone () from /lib64/libc.so.6

If you look at the frame #2, the code is:

488	 if (he-&gt;srcline) {
489          he-&gt;srcline = strdup(he-&gt;srcline);
490          if (he-&gt;srcline == NULL)
491              goto err_rawdata;
492	 }

If he-&gt;srcline is not NULL (it is not NULL if it is uninitialized rubbish),
it gets strdupped and strdupping a rubbish random string causes the problem.

Also, if you look at the commit 1fb7d06a509e, it adds the srcline property
into the struct, but not initializing it everywhere needed.

Committer notes:

Now I see, when using --ignore-callees=do_idle we end up here at line
2189 in add_callchain_ip():

2181         if (al.sym != NULL) {
2182                 if (perf_hpp_list.parent &amp;&amp; !*parent &amp;&amp;
2183                     symbol__match_regex(al.sym, &amp;parent_regex))
2184                         *parent = al.sym;
2185                 else if (have_ignore_callees &amp;&amp; root_al &amp;&amp;
2186                   symbol__match_regex(al.sym, &amp;ignore_callees_regex)) {
2187                         /* Treat this symbol as the root,
2188                            forgetting its callees. */
2189                         *root_al = al;
2190                         callchain_cursor_reset(cursor);
2191                 }
2192         }

And the al that doesn't have the -&gt;srcline field initialized will be
copied to the root_al, so then, back to:

1211 int hist_entry_iter__add(struct hist_entry_iter *iter, struct addr_location *al,
1212                          int max_stack_depth, void *arg)
1213 {
1214         int err, err2;
1215         struct map *alm = NULL;
1216
1217         if (al)
1218                 alm = map__get(al-&gt;map);
1219
1220         err = sample__resolve_callchain(iter-&gt;sample, &amp;callchain_cursor, &amp;iter-&gt;parent,
1221                                         iter-&gt;evsel, al, max_stack_depth);
1222         if (err) {
1223                 map__put(alm);
1224                 return err;
1225         }
1226
1227         err = iter-&gt;ops-&gt;prepare_entry(iter, al);
1228         if (err)
1229                 goto out;
1230
1231         err = iter-&gt;ops-&gt;add_single_entry(iter, al);
1232         if (err)
1233                 goto out;
1234

That al at line 1221 is what hist_entry_iter__add() (called from
sample__resolve_callchain()) saw as 'root_al', and then:

        iter-&gt;ops-&gt;add_single_entry(iter, al);

will go on with al-&gt;srcline with a bogus value, I'll add the above
sequence to the cset and apply, thanks!

Signed-off-by: Michael Petlan &lt;mpetlan@redhat.com&gt;
CC: Milian Wolff &lt;milian.wolff@kdab.com&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&gt;
Fixes: 1fb7d06a509e ("perf report Use srcline from callchain for hist entries")
Link: https //lore.kernel.org/r/20210719145332.29747-1-mpetlan@redhat.com
Reported-by: Juri Lelli &lt;jlelli@redhat.com&gt;
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>perf machine: Fix refcount usage when processing PERF_RECORD_KSYMBOL</title>
<updated>2021-06-19T13:06:46+00:00</updated>
<author>
<name>Riccardo Mancini</name>
<email>rickyman7@gmail.com</email>
</author>
<published>2021-06-12T17:37:48+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=c087e9480cf33672ef2c6cce4348d754988b8437'/>
<id>urn:sha1:c087e9480cf33672ef2c6cce4348d754988b8437</id>
<content type='text'>
ASan reported a memory leak of BPF-related ksymbols map and dso. The
leak is caused by refount never reaching 0, due to missing __put calls
in the function machine__process_ksymbol_register.

Once the dso is inserted in the map, dso__put() should be called
(map__new2() increases the refcount to 2).

The same thing applies for the map when it's inserted into maps
(maps__insert() increases the refcount to 2).

  $ sudo ./perf record -- sleep 5
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.025 MB perf.data (8 samples) ]

  =================================================================
  ==297735==ERROR: LeakSanitizer: detected memory leaks

  Direct leak of 6992 byte(s) in 19 object(s) allocated from:
      #0 0x4f43c7 in calloc (/home/user/linux/tools/perf/perf+0x4f43c7)
      #1 0x8e4e53 in map__new2 /home/user/linux/tools/perf/util/map.c:216:20
      #2 0x8cf68c in machine__process_ksymbol_register /home/user/linux/tools/perf/util/machine.c:778:10
      [...]

  Indirect leak of 8702 byte(s) in 19 object(s) allocated from:
      #0 0x4f43c7 in calloc (/home/user/linux/tools/perf/perf+0x4f43c7)
      #1 0x8728d7 in dso__new_id /home/user/linux/tools/perf/util/dso.c:1256:20
      #2 0x872015 in dso__new /home/user/linux/tools/perf/util/dso.c:1295:9
      #3 0x8cf623 in machine__process_ksymbol_register /home/user/linux/tools/perf/util/machine.c:774:21
      [...]

  Indirect leak of 1520 byte(s) in 19 object(s) allocated from:
      #0 0x4f43c7 in calloc (/home/user/linux/tools/perf/perf+0x4f43c7)
      #1 0x87b3da in symbol__new /home/user/linux/tools/perf/util/symbol.c:269:23
      #2 0x888954 in map__process_kallsym_symbol /home/user/linux/tools/perf/util/symbol.c:710:8
      [...]

  Indirect leak of 1406 byte(s) in 19 object(s) allocated from:
      #0 0x4f43c7 in calloc (/home/user/linux/tools/perf/perf+0x4f43c7)
      #1 0x87b3da in symbol__new /home/user/linux/tools/perf/util/symbol.c:269:23
      #2 0x8cfbd8 in machine__process_ksymbol_register /home/user/linux/tools/perf/util/machine.c:803:8
      [...]

Signed-off-by: Riccardo Mancini &lt;rickyman7@gmail.com&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Ian Rogers &lt;irogers@google.com&gt;
Cc: Jiapeng Chong &lt;jiapeng.chong@linux.alibaba.com&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&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;
Cc: Tommi Rantala &lt;tommi.t.rantala@nokia.com&gt;
Link: http://lore.kernel.org/lkml/20210612173751.188582-1-rickyman7@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>perf tools: Fix various typos in comments</title>
<updated>2021-03-23T20:13:43+00:00</updated>
<author>
<name>Ingo Molnar</name>
<email>mingo@kernel.org</email>
</author>
<published>2021-03-23T16:09:15+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=4d39c89f0b94bf4a6e1ccf42702e7d80d210a5fd'/>
<id>urn:sha1:4d39c89f0b94bf4a6e1ccf42702e7d80d210a5fd</id>
<content type='text'>
Fix ~124 single-word typos and a few spelling errors in the perf tooling code,
accumulated over the years.

Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Link: https://lore.kernel.org/r/20210321113734.GA248990@gmail.com
Link: http://lore.kernel.org/lkml/20210323160915.GA61903@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>perf machine: Assign boolean values to a bool variable</title>
<updated>2021-03-09T12:09:45+00:00</updated>
<author>
<name>Jiapeng Chong</name>
<email>jiapeng.chong@linux.alibaba.com</email>
</author>
<published>2021-03-09T10:11:09+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=83ff0f93b0803700b018f6cce06f50439dc1348c'/>
<id>urn:sha1:83ff0f93b0803700b018f6cce06f50439dc1348c</id>
<content type='text'>
Fix the following coccicheck warnings:

./tools/perf/util/machine.c:2041:9-10: WARNING: return of 0/1 in
function 'symbol__match_regex' with return type bool.

Reported-by: Abaci Robot &lt;abaci@linux.alibaba.com&gt;
Signed-off-by: Jiapeng Chong &lt;jiapeng.chong@linux.alibaba.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Alexei Starovoitov &lt;ast@kernel.org&gt;
Cc: Andrii Nakryiko &lt;andrii@kernel.org&gt;
Cc: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: John Fastabend &lt;john.fastabend@gmail.com&gt;
Cc: KP Singh &lt;kpsingh@kernel.org&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Martin KaFai Lau &lt;kafai@fb.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Song Liu &lt;songliubraving@fb.com&gt;
Cc: Yonghong Song &lt;yhs@fb.com&gt;
Cc: bpf@vger.kernel.org
Cc: netdev@vger.kernel.org
Link: http://lore.kernel.org/lkml/1615284669-82139-1-git-send-email-jiapeng.chong@linux.alibaba.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>perf machine: Factor out machine__idle_thread()</title>
<updated>2021-02-18T19:14:33+00:00</updated>
<author>
<name>Adrian Hunter</name>
<email>adrian.hunter@intel.com</email>
</author>
<published>2021-02-18T09:57:56+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=3035cb6cbd2d62a764fa451ed9534eafdd0b446c'/>
<id>urn:sha1:3035cb6cbd2d62a764fa451ed9534eafdd0b446c</id>
<content type='text'>
Factor out machine__idle_thread() so it can be re-used for guest machines.

A thread is needed to find executable code, even for the guest kernel. To
avoid possible future pid number conflicts, the idle thread can be used.

Signed-off-by: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Acked-by: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&gt;
Link: https://lore.kernel.org/r/20210218095801.19576-7-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>perf machine: Factor out machines__find_guest()</title>
<updated>2021-02-18T19:14:14+00:00</updated>
<author>
<name>Adrian Hunter</name>
<email>adrian.hunter@intel.com</email>
</author>
<published>2021-02-18T09:57:55+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=fcda5ff711d9ddb7a92fff38b2cc153be8123c0e'/>
<id>urn:sha1:fcda5ff711d9ddb7a92fff38b2cc153be8123c0e</id>
<content type='text'>
Factor out machines__find_guest() so it can be re-used.

Signed-off-by: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Acked-by: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&gt;
Link: https://lore.kernel.org/r/20210218095801.19576-6-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>Merge remote-tracking branch 'torvalds/master' into perf/core</title>
<updated>2021-01-20T17:35:31+00:00</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
<email>acme@redhat.com</email>
</author>
<published>2021-01-20T17:35:31+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=cd07e536b0201fceffd90a701bfb1e1fc07fcd34'/>
<id>urn:sha1:cd07e536b0201fceffd90a701bfb1e1fc07fcd34</id>
<content type='text'>
To pick up fixes.

Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>perf intel-pt: Fix 'CPU too large' error</title>
<updated>2021-01-15T20:28:27+00:00</updated>
<author>
<name>Adrian Hunter</name>
<email>adrian.hunter@intel.com</email>
</author>
<published>2021-01-07T17:41:59+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=5501e9229a80d95a1ea68609f44c447a75d23ed5'/>
<id>urn:sha1:5501e9229a80d95a1ea68609f44c447a75d23ed5</id>
<content type='text'>
In some cases, the number of cpus (nr_cpus_online) is confused with the
maximum cpu number (nr_cpus_avail), which results in the error in the
example below:

Example on system with 8 cpus:

 Before:
   # echo 0 &gt; /sys/devices/system/cpu/cpu2/online
   # ./perf record --kcore -e intel_pt// taskset --cpu-list 7 uname
   Linux
   [ perf record: Woken up 1 times to write data ]
   [ perf record: Captured and wrote 0.147 MB perf.data ]
   # ./perf script --itrace=e
   Requested CPU 7 too large. Consider raising MAX_NR_CPUS
   0x25908 [0x8]: failed to process type: 68 [Invalid argument]

 After:
   # ./perf script --itrace=e
   #

Fixes: 8c7274691f0d ("perf machine: Replace MAX_NR_CPUS with perf_env::nr_cpus_online")
Fixes: 7df4e36a4785 ("perf session: Replace MAX_NR_CPUS with perf_env::nr_cpus_online")
Signed-off-by: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Tested-by: Kan Liang &lt;kan.liang@linux.intel.com&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: stable@vger.kernel.org
Link: http://lore.kernel.org/lkml/20210107174159.24897-1-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
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