<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/tools, branch v5.4.73</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>selftests/bpf: Fix test_sysctl_loop{1, 2} failure due to clang change</title>
<updated>2020-10-29T08:58:07+00:00</updated>
<author>
<name>Yonghong Song</name>
<email>yhs@fb.com</email>
</author>
<published>2020-09-09T17:15:42+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=061d2f3fce454c972f984e28322e9fcca0c23b11'/>
<id>061d2f3fce454c972f984e28322e9fcca0c23b11</id>
<content type='text'>
[ Upstream commit 7fb5eefd76394cfefb380724a87ca40b47d44405 ]

Andrii reported that with latest clang, when building selftests, we have
error likes:
  error: progs/test_sysctl_loop1.c:23:16: in function sysctl_tcp_mem i32 (%struct.bpf_sysctl*):
  Looks like the BPF stack limit of 512 bytes is exceeded.
  Please move large on stack variables into BPF per-cpu array map.

The error is triggered by the following LLVM patch:
  https://reviews.llvm.org/D87134

For example, the following code is from test_sysctl_loop1.c:
  static __always_inline int is_tcp_mem(struct bpf_sysctl *ctx)
  {
    volatile char tcp_mem_name[] = "net/ipv4/tcp_mem/very_very_very_very_long_pointless_string";
    ...
  }
Without the above LLVM patch, the compiler did optimization to load the string
(59 bytes long) with 7 64bit loads, 1 8bit load and 1 16bit load,
occupying 64 byte stack size.

With the above LLVM patch, the compiler only uses 8bit loads, but subregister is 32bit.
So stack requirements become 4 * 59 = 236 bytes. Together with other stuff on
the stack, total stack size exceeds 512 bytes, hence compiler complains and quits.

To fix the issue, removing "volatile" key word or changing "volatile" to
"const"/"static const" does not work, the string is put in .rodata.str1.1 section,
which libbpf did not process it and errors out with
  libbpf: elf: skipping unrecognized data section(6) .rodata.str1.1
  libbpf: prog 'sysctl_tcp_mem': bad map relo against '.L__const.is_tcp_mem.tcp_mem_name'
          in section '.rodata.str1.1'

Defining the string const as global variable can fix the issue as it puts the string constant
in '.rodata' section which is recognized by libbpf. In the future, when libbpf can process
'.rodata.str*.*' properly, the global definition can be changed back to local definition.

Defining tcp_mem_name as a global, however, triggered a verifier failure.
   ./test_progs -n 7/21
  libbpf: load bpf program failed: Permission denied
  libbpf: -- BEGIN DUMP LOG ---
  libbpf:
  invalid stack off=0 size=1
  verification time 6975 usec
  stack depth 160+64
  processed 889 insns (limit 1000000) max_states_per_insn 4 total_states
  14 peak_states 14 mark_read 10

  libbpf: -- END LOG --
  libbpf: failed to load program 'sysctl_tcp_mem'
  libbpf: failed to load object 'test_sysctl_loop2.o'
  test_bpf_verif_scale:FAIL:114
  #7/21 test_sysctl_loop2.o:FAIL
This actually exposed a bpf program bug. In test_sysctl_loop{1,2}, we have code
like
  const char tcp_mem_name[] = "&lt;...long string...&gt;";
  ...
  char name[64];
  ...
  for (i = 0; i &lt; sizeof(tcp_mem_name); ++i)
      if (name[i] != tcp_mem_name[i])
          return 0;
In the above code, if sizeof(tcp_mem_name) &gt; 64, name[i] access may be
out of bound. The sizeof(tcp_mem_name) is 59 for test_sysctl_loop1.c and
79 for test_sysctl_loop2.c.

Without promotion-to-global change, old compiler generates code where
the overflowed stack access is actually filled with valid value, so hiding
the bpf program bug. With promotion-to-global change, the code is different,
more specifically, the previous loading constants to stack is gone, and
"name" occupies stack[-64:0] and overflow access triggers a verifier error.
To fix the issue, adjust "name" buffer size properly.

Reported-by: Andrii Nakryiko &lt;andriin@fb.com&gt;
Signed-off-by: Yonghong Song &lt;yhs@fb.com&gt;
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Acked-by: Andrii Nakryiko &lt;andriin@fb.com&gt;
Link: https://lore.kernel.org/bpf/20200909171542.3673449-1-yhs@fb.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 7fb5eefd76394cfefb380724a87ca40b47d44405 ]

Andrii reported that with latest clang, when building selftests, we have
error likes:
  error: progs/test_sysctl_loop1.c:23:16: in function sysctl_tcp_mem i32 (%struct.bpf_sysctl*):
  Looks like the BPF stack limit of 512 bytes is exceeded.
  Please move large on stack variables into BPF per-cpu array map.

The error is triggered by the following LLVM patch:
  https://reviews.llvm.org/D87134

For example, the following code is from test_sysctl_loop1.c:
  static __always_inline int is_tcp_mem(struct bpf_sysctl *ctx)
  {
    volatile char tcp_mem_name[] = "net/ipv4/tcp_mem/very_very_very_very_long_pointless_string";
    ...
  }
Without the above LLVM patch, the compiler did optimization to load the string
(59 bytes long) with 7 64bit loads, 1 8bit load and 1 16bit load,
occupying 64 byte stack size.

With the above LLVM patch, the compiler only uses 8bit loads, but subregister is 32bit.
So stack requirements become 4 * 59 = 236 bytes. Together with other stuff on
the stack, total stack size exceeds 512 bytes, hence compiler complains and quits.

To fix the issue, removing "volatile" key word or changing "volatile" to
"const"/"static const" does not work, the string is put in .rodata.str1.1 section,
which libbpf did not process it and errors out with
  libbpf: elf: skipping unrecognized data section(6) .rodata.str1.1
  libbpf: prog 'sysctl_tcp_mem': bad map relo against '.L__const.is_tcp_mem.tcp_mem_name'
          in section '.rodata.str1.1'

Defining the string const as global variable can fix the issue as it puts the string constant
in '.rodata' section which is recognized by libbpf. In the future, when libbpf can process
'.rodata.str*.*' properly, the global definition can be changed back to local definition.

Defining tcp_mem_name as a global, however, triggered a verifier failure.
   ./test_progs -n 7/21
  libbpf: load bpf program failed: Permission denied
  libbpf: -- BEGIN DUMP LOG ---
  libbpf:
  invalid stack off=0 size=1
  verification time 6975 usec
  stack depth 160+64
  processed 889 insns (limit 1000000) max_states_per_insn 4 total_states
  14 peak_states 14 mark_read 10

  libbpf: -- END LOG --
  libbpf: failed to load program 'sysctl_tcp_mem'
  libbpf: failed to load object 'test_sysctl_loop2.o'
  test_bpf_verif_scale:FAIL:114
  #7/21 test_sysctl_loop2.o:FAIL
This actually exposed a bpf program bug. In test_sysctl_loop{1,2}, we have code
like
  const char tcp_mem_name[] = "&lt;...long string...&gt;";
  ...
  char name[64];
  ...
  for (i = 0; i &lt; sizeof(tcp_mem_name); ++i)
      if (name[i] != tcp_mem_name[i])
          return 0;
In the above code, if sizeof(tcp_mem_name) &gt; 64, name[i] access may be
out of bound. The sizeof(tcp_mem_name) is 59 for test_sysctl_loop1.c and
79 for test_sysctl_loop2.c.

Without promotion-to-global change, old compiler generates code where
the overflowed stack access is actually filled with valid value, so hiding
the bpf program bug. With promotion-to-global change, the code is different,
more specifically, the previous loading constants to stack is gone, and
"name" occupies stack[-64:0] and overflow access triggers a verifier error.
To fix the issue, adjust "name" buffer size properly.

Reported-by: Andrii Nakryiko &lt;andriin@fb.com&gt;
Signed-off-by: Yonghong Song &lt;yhs@fb.com&gt;
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Acked-by: Andrii Nakryiko &lt;andriin@fb.com&gt;
Link: https://lore.kernel.org/bpf/20200909171542.3673449-1-yhs@fb.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>selftests/powerpc: Fix eeh-basic.sh exit codes</title>
<updated>2020-10-29T08:57:52+00:00</updated>
<author>
<name>Oliver O'Halloran</name>
<email>oohall@gmail.com</email>
</author>
<published>2020-10-14T02:47:11+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=f08ae0c461980409bcb048d0e71ede12c64bc048'/>
<id>f08ae0c461980409bcb048d0e71ede12c64bc048</id>
<content type='text'>
[ Upstream commit 996f9e0f93f16211945c8d5f18f296a88cb32f91 ]

The kselftests test running infrastructure expects tests to finish with an
exit code of 4 if the test decided it should be skipped. Currently
eeh-basic.sh exits with the number of devices that failed to recover, so if
four devices didn't recover we'll report a skip instead of a fail.

Fix this by checking if the return code is non-zero and report success
and failure by returning 0 or 1 respectively. For the cases where should
actually skip return 4.

Fixes: 85d86c8aa52e ("selftests/powerpc: Add basic EEH selftest")
Signed-off-by: Oliver O'Halloran &lt;oohall@gmail.com&gt;
Signed-off-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Link: https://lore.kernel.org/r/20201014024711.1138386-1-oohall@gmail.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 996f9e0f93f16211945c8d5f18f296a88cb32f91 ]

The kselftests test running infrastructure expects tests to finish with an
exit code of 4 if the test decided it should be skipped. Currently
eeh-basic.sh exits with the number of devices that failed to recover, so if
four devices didn't recover we'll report a skip instead of a fail.

Fix this by checking if the return code is non-zero and report success
and failure by returning 0 or 1 respectively. For the cases where should
actually skip return 4.

Fixes: 85d86c8aa52e ("selftests/powerpc: Add basic EEH selftest")
Signed-off-by: Oliver O'Halloran &lt;oohall@gmail.com&gt;
Signed-off-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Link: https://lore.kernel.org/r/20201014024711.1138386-1-oohall@gmail.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf stat: Skip duration_time in setup_system_wide</title>
<updated>2020-10-29T08:57:50+00:00</updated>
<author>
<name>Jin Yao</name>
<email>yao.jin@linux.intel.com</email>
</author>
<published>2020-09-22T01:50:04+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=1e583b2948aeb65338dd7e14e87c6d77ad7bf982'/>
<id>1e583b2948aeb65338dd7e14e87c6d77ad7bf982</id>
<content type='text'>
[ Upstream commit 002a3d690f95804bdef6b70b26154103518e13d9 ]

Some metrics (such as DRAM_BW_Use) consists of uncore events and
duration_time. For uncore events, counter-&gt;core.system_wide is true. But
for duration_time, counter-&gt;core.system_wide is false so
target.system_wide is set to false.

Then 'enable_on_exec' is set in perf_event_attr of uncore event.  Kernel
will return error when trying to open the uncore event.

This patch skips the duration_time in setup_system_wide then
target.system_wide will be set to true for the evlist of uncore events +
duration_time.

Before (tested on skylake desktop):

  # perf stat -M DRAM_BW_Use -- sleep 1
  Error:
  The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (arb/event=0x84,umask=0x1/).
  /bin/dmesg | grep -i perf may provide additional information.

After:

  # perf stat -M DRAM_BW_Use -- sleep 1

   Performance counter stats for 'system wide':

                169      arb/event=0x84,umask=0x1/ #     0.00 DRAM_BW_Use
             40,427      arb/event=0x81,umask=0x1/
      1,000,902,197 ns   duration_time

        1.000902197 seconds time elapsed

Fixes: e3ba76deef23064f ("perf tools: Force uncore events to system wide monitoring")
Signed-off-by: Jin Yao &lt;yao.jin@linux.intel.com&gt;
Tested-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Jin Yao &lt;yao.jin@intel.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Kan Liang &lt;kan.liang@linux.intel.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Link: http://lore.kernel.org/lkml/20200922015004.30114-1-yao.jin@linux.intel.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 002a3d690f95804bdef6b70b26154103518e13d9 ]

Some metrics (such as DRAM_BW_Use) consists of uncore events and
duration_time. For uncore events, counter-&gt;core.system_wide is true. But
for duration_time, counter-&gt;core.system_wide is false so
target.system_wide is set to false.

Then 'enable_on_exec' is set in perf_event_attr of uncore event.  Kernel
will return error when trying to open the uncore event.

This patch skips the duration_time in setup_system_wide then
target.system_wide will be set to true for the evlist of uncore events +
duration_time.

Before (tested on skylake desktop):

  # perf stat -M DRAM_BW_Use -- sleep 1
  Error:
  The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (arb/event=0x84,umask=0x1/).
  /bin/dmesg | grep -i perf may provide additional information.

After:

  # perf stat -M DRAM_BW_Use -- sleep 1

   Performance counter stats for 'system wide':

                169      arb/event=0x84,umask=0x1/ #     0.00 DRAM_BW_Use
             40,427      arb/event=0x81,umask=0x1/
      1,000,902,197 ns   duration_time

        1.000902197 seconds time elapsed

Fixes: e3ba76deef23064f ("perf tools: Force uncore events to system wide monitoring")
Signed-off-by: Jin Yao &lt;yao.jin@linux.intel.com&gt;
Tested-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Jin Yao &lt;yao.jin@intel.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Kan Liang &lt;kan.liang@linux.intel.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Link: http://lore.kernel.org/lkml/20200922015004.30114-1-yao.jin@linux.intel.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>perf intel-pt: Fix "context_switch event has no tid" error</title>
<updated>2020-10-29T08:57:50+00:00</updated>
<author>
<name>Adrian Hunter</name>
<email>adrian.hunter@intel.com</email>
</author>
<published>2020-09-09T08:49:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=0ff75bfed10d20d82f11b1ab02a3d6ec54180159'/>
<id>0ff75bfed10d20d82f11b1ab02a3d6ec54180159</id>
<content type='text'>
[ Upstream commit 7d537a8d2e76bc4fc71e34545ceaa463ac2cd928 ]

A context_switch event can have no tid because pids can be detached from
a task while the task is still running (in do_exit()). Note this won't
happen with per-task contexts because then tracing stops at
perf_event_exit_task()

If a task with no tid gets preempted, or a dying task gets preempted and
its parent releases it, when it subsequently gets switched back in,
Intel PT will not be able to determine what task is running and prints
an error "context_switch event has no tid". However, it is not really an
error because the task is in kernel space and the decoder can continue
to decode successfully. Fix by changing the error to be only a logged
message, and make allowance for tid == -1.

Example:

  Using 5.9-rc4 with Preemptible Kernel (Low-Latency Desktop) e.g.
  $ uname -r
  5.9.0-rc4
  $ grep PREEMPT .config
  # CONFIG_PREEMPT_NONE is not set
  # CONFIG_PREEMPT_VOLUNTARY is not set
  CONFIG_PREEMPT=y
  CONFIG_PREEMPT_COUNT=y
  CONFIG_PREEMPTION=y
  CONFIG_PREEMPT_RCU=y
  CONFIG_PREEMPT_NOTIFIERS=y
  CONFIG_DRM_I915_PREEMPT_TIMEOUT=640
  CONFIG_DEBUG_PREEMPT=y
  # CONFIG_PREEMPT_TRACER is not set
  # CONFIG_PREEMPTIRQ_DELAY_TEST is not set

Before:

  $ cat forkit.c

  #include &lt;sys/types.h&gt;
  #include &lt;unistd.h&gt;
  #include &lt;sys/wait.h&gt;

  int main()
  {
          pid_t child;
          int status = 0;

          child = fork();
          if (child == 0)
                  return 123;
          wait(&amp;status);
          return 0;
  }

  $ gcc -o forkit forkit.c
  $ sudo ~/bin/perf record --kcore -a -m,64M -e intel_pt/cyc/k &amp;
  [1] 11016
  $ taskset 2 ./forkit
  $ sudo pkill perf
  $ [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 17.262 MB perf.data ]

  [1]+  Terminated              sudo ~/bin/perf record --kcore -a -m,64M -e intel_pt/cyc/k
  $ sudo ~/bin/perf script --show-task-events --show-switch-events --itrace=iqqe-o -C 1 --ns | grep -C 2 forkit
  context_switch event has no tid
           taskset 11019 [001] 66663.270045029:          1 instructions:k:  ffffffffb1d9f844 strnlen_user+0xb4 ([kernel.kallsyms])
           taskset 11019 [001] 66663.270201816:          1 instructions:k:  ffffffffb1a83121 unmap_page_range+0x561 ([kernel.kallsyms])
            forkit 11019 [001] 66663.270327553: PERF_RECORD_COMM exec: forkit:11019/11019
            forkit 11019 [001] 66663.270420028:          1 instructions:k:  ffffffffb1db9537 __clear_user+0x27 ([kernel.kallsyms])
            forkit 11019 [001] 66663.270648704:          1 instructions:k:  ffffffffb18829e6 do_user_addr_fault+0xf6 ([kernel.kallsyms])
            forkit 11019 [001] 66663.270833163:          1 instructions:k:  ffffffffb230a825 irqentry_exit_to_user_mode+0x15 ([kernel.kallsyms])
            forkit 11019 [001] 66663.271092359:          1 instructions:k:  ffffffffb1aea3d9 lock_page_memcg+0x9 ([kernel.kallsyms])
            forkit 11019 [001] 66663.271207092: PERF_RECORD_FORK(11020:11020):(11019:11019)
            forkit 11019 [001] 66663.271234775: PERF_RECORD_SWITCH_CPU_WIDE OUT          next pid/tid: 11020/11020
            forkit 11020 [001] 66663.271238407: PERF_RECORD_SWITCH_CPU_WIDE IN           prev pid/tid: 11019/11019
            forkit 11020 [001] 66663.271312066:          1 instructions:k:  ffffffffb1a88140 handle_mm_fault+0x10 ([kernel.kallsyms])
            forkit 11020 [001] 66663.271476225: PERF_RECORD_EXIT(11020:11020):(11019:11019)
            forkit 11020 [001] 66663.271497488: PERF_RECORD_SWITCH_CPU_WIDE OUT preempt  next pid/tid: 11019/11019
            forkit 11019 [001] 66663.271500523: PERF_RECORD_SWITCH_CPU_WIDE IN           prev pid/tid: 11020/11020
            forkit 11019 [001] 66663.271517241:          1 instructions:k:  ffffffffb24012cd error_entry+0x6d ([kernel.kallsyms])
            forkit 11019 [001] 66663.271664080: PERF_RECORD_EXIT(11019:11019):(1386:1386)

After:

  $ sudo ~/bin/perf script --show-task-events --show-switch-events --itrace=iqqe-o -C 1 --ns | grep -C 2 forkit
           taskset 11019 [001] 66663.270045029:          1 instructions:k:  ffffffffb1d9f844 strnlen_user+0xb4 ([kernel.kallsyms])
           taskset 11019 [001] 66663.270201816:          1 instructions:k:  ffffffffb1a83121 unmap_page_range+0x561 ([kernel.kallsyms])
            forkit 11019 [001] 66663.270327553: PERF_RECORD_COMM exec: forkit:11019/11019
            forkit 11019 [001] 66663.270420028:          1 instructions:k:  ffffffffb1db9537 __clear_user+0x27 ([kernel.kallsyms])
            forkit 11019 [001] 66663.270648704:          1 instructions:k:  ffffffffb18829e6 do_user_addr_fault+0xf6 ([kernel.kallsyms])
            forkit 11019 [001] 66663.270833163:          1 instructions:k:  ffffffffb230a825 irqentry_exit_to_user_mode+0x15 ([kernel.kallsyms])
            forkit 11019 [001] 66663.271092359:          1 instructions:k:  ffffffffb1aea3d9 lock_page_memcg+0x9 ([kernel.kallsyms])
            forkit 11019 [001] 66663.271207092: PERF_RECORD_FORK(11020:11020):(11019:11019)
            forkit 11019 [001] 66663.271234775: PERF_RECORD_SWITCH_CPU_WIDE OUT          next pid/tid: 11020/11020
            forkit 11020 [001] 66663.271238407: PERF_RECORD_SWITCH_CPU_WIDE IN           prev pid/tid: 11019/11019
            forkit 11020 [001] 66663.271312066:          1 instructions:k:  ffffffffb1a88140 handle_mm_fault+0x10 ([kernel.kallsyms])
            forkit 11020 [001] 66663.271476225: PERF_RECORD_EXIT(11020:11020):(11019:11019)
            forkit 11020 [001] 66663.271497488: PERF_RECORD_SWITCH_CPU_WIDE OUT preempt  next pid/tid: 11019/11019
            forkit 11019 [001] 66663.271500523: PERF_RECORD_SWITCH_CPU_WIDE IN           prev pid/tid: 11020/11020
            forkit 11019 [001] 66663.271517241:          1 instructions:k:  ffffffffb24012cd error_entry+0x6d ([kernel.kallsyms])
            forkit 11019 [001] 66663.271664080: PERF_RECORD_EXIT(11019:11019):(1386:1386)
            forkit 11019 [001] 66663.271688752: PERF_RECORD_SWITCH_CPU_WIDE OUT          next pid/tid:    -1/-1
               :-1    -1 [001] 66663.271692086: PERF_RECORD_SWITCH_CPU_WIDE IN           prev pid/tid: 11019/11019
                :-1    -1 [001] 66663.271707466:          1 instructions:k:  ffffffffb18eb096 update_load_avg+0x306 ([kernel.kallsyms])

Fixes: 86c2786994bd7c ("perf intel-pt: Add support for PERF_RECORD_SWITCH")
Signed-off-by: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Yu-cheng Yu &lt;yu-cheng.yu@intel.com&gt;
Link: http://lore.kernel.org/lkml/20200909084923.9096-3-adrian.hunter@intel.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 7d537a8d2e76bc4fc71e34545ceaa463ac2cd928 ]

A context_switch event can have no tid because pids can be detached from
a task while the task is still running (in do_exit()). Note this won't
happen with per-task contexts because then tracing stops at
perf_event_exit_task()

If a task with no tid gets preempted, or a dying task gets preempted and
its parent releases it, when it subsequently gets switched back in,
Intel PT will not be able to determine what task is running and prints
an error "context_switch event has no tid". However, it is not really an
error because the task is in kernel space and the decoder can continue
to decode successfully. Fix by changing the error to be only a logged
message, and make allowance for tid == -1.

Example:

  Using 5.9-rc4 with Preemptible Kernel (Low-Latency Desktop) e.g.
  $ uname -r
  5.9.0-rc4
  $ grep PREEMPT .config
  # CONFIG_PREEMPT_NONE is not set
  # CONFIG_PREEMPT_VOLUNTARY is not set
  CONFIG_PREEMPT=y
  CONFIG_PREEMPT_COUNT=y
  CONFIG_PREEMPTION=y
  CONFIG_PREEMPT_RCU=y
  CONFIG_PREEMPT_NOTIFIERS=y
  CONFIG_DRM_I915_PREEMPT_TIMEOUT=640
  CONFIG_DEBUG_PREEMPT=y
  # CONFIG_PREEMPT_TRACER is not set
  # CONFIG_PREEMPTIRQ_DELAY_TEST is not set

Before:

  $ cat forkit.c

  #include &lt;sys/types.h&gt;
  #include &lt;unistd.h&gt;
  #include &lt;sys/wait.h&gt;

  int main()
  {
          pid_t child;
          int status = 0;

          child = fork();
          if (child == 0)
                  return 123;
          wait(&amp;status);
          return 0;
  }

  $ gcc -o forkit forkit.c
  $ sudo ~/bin/perf record --kcore -a -m,64M -e intel_pt/cyc/k &amp;
  [1] 11016
  $ taskset 2 ./forkit
  $ sudo pkill perf
  $ [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 17.262 MB perf.data ]

  [1]+  Terminated              sudo ~/bin/perf record --kcore -a -m,64M -e intel_pt/cyc/k
  $ sudo ~/bin/perf script --show-task-events --show-switch-events --itrace=iqqe-o -C 1 --ns | grep -C 2 forkit
  context_switch event has no tid
           taskset 11019 [001] 66663.270045029:          1 instructions:k:  ffffffffb1d9f844 strnlen_user+0xb4 ([kernel.kallsyms])
           taskset 11019 [001] 66663.270201816:          1 instructions:k:  ffffffffb1a83121 unmap_page_range+0x561 ([kernel.kallsyms])
            forkit 11019 [001] 66663.270327553: PERF_RECORD_COMM exec: forkit:11019/11019
            forkit 11019 [001] 66663.270420028:          1 instructions:k:  ffffffffb1db9537 __clear_user+0x27 ([kernel.kallsyms])
            forkit 11019 [001] 66663.270648704:          1 instructions:k:  ffffffffb18829e6 do_user_addr_fault+0xf6 ([kernel.kallsyms])
            forkit 11019 [001] 66663.270833163:          1 instructions:k:  ffffffffb230a825 irqentry_exit_to_user_mode+0x15 ([kernel.kallsyms])
            forkit 11019 [001] 66663.271092359:          1 instructions:k:  ffffffffb1aea3d9 lock_page_memcg+0x9 ([kernel.kallsyms])
            forkit 11019 [001] 66663.271207092: PERF_RECORD_FORK(11020:11020):(11019:11019)
            forkit 11019 [001] 66663.271234775: PERF_RECORD_SWITCH_CPU_WIDE OUT          next pid/tid: 11020/11020
            forkit 11020 [001] 66663.271238407: PERF_RECORD_SWITCH_CPU_WIDE IN           prev pid/tid: 11019/11019
            forkit 11020 [001] 66663.271312066:          1 instructions:k:  ffffffffb1a88140 handle_mm_fault+0x10 ([kernel.kallsyms])
            forkit 11020 [001] 66663.271476225: PERF_RECORD_EXIT(11020:11020):(11019:11019)
            forkit 11020 [001] 66663.271497488: PERF_RECORD_SWITCH_CPU_WIDE OUT preempt  next pid/tid: 11019/11019
            forkit 11019 [001] 66663.271500523: PERF_RECORD_SWITCH_CPU_WIDE IN           prev pid/tid: 11020/11020
            forkit 11019 [001] 66663.271517241:          1 instructions:k:  ffffffffb24012cd error_entry+0x6d ([kernel.kallsyms])
            forkit 11019 [001] 66663.271664080: PERF_RECORD_EXIT(11019:11019):(1386:1386)

After:

  $ sudo ~/bin/perf script --show-task-events --show-switch-events --itrace=iqqe-o -C 1 --ns | grep -C 2 forkit
           taskset 11019 [001] 66663.270045029:          1 instructions:k:  ffffffffb1d9f844 strnlen_user+0xb4 ([kernel.kallsyms])
           taskset 11019 [001] 66663.270201816:          1 instructions:k:  ffffffffb1a83121 unmap_page_range+0x561 ([kernel.kallsyms])
            forkit 11019 [001] 66663.270327553: PERF_RECORD_COMM exec: forkit:11019/11019
            forkit 11019 [001] 66663.270420028:          1 instructions:k:  ffffffffb1db9537 __clear_user+0x27 ([kernel.kallsyms])
            forkit 11019 [001] 66663.270648704:          1 instructions:k:  ffffffffb18829e6 do_user_addr_fault+0xf6 ([kernel.kallsyms])
            forkit 11019 [001] 66663.270833163:          1 instructions:k:  ffffffffb230a825 irqentry_exit_to_user_mode+0x15 ([kernel.kallsyms])
            forkit 11019 [001] 66663.271092359:          1 instructions:k:  ffffffffb1aea3d9 lock_page_memcg+0x9 ([kernel.kallsyms])
            forkit 11019 [001] 66663.271207092: PERF_RECORD_FORK(11020:11020):(11019:11019)
            forkit 11019 [001] 66663.271234775: PERF_RECORD_SWITCH_CPU_WIDE OUT          next pid/tid: 11020/11020
            forkit 11020 [001] 66663.271238407: PERF_RECORD_SWITCH_CPU_WIDE IN           prev pid/tid: 11019/11019
            forkit 11020 [001] 66663.271312066:          1 instructions:k:  ffffffffb1a88140 handle_mm_fault+0x10 ([kernel.kallsyms])
            forkit 11020 [001] 66663.271476225: PERF_RECORD_EXIT(11020:11020):(11019:11019)
            forkit 11020 [001] 66663.271497488: PERF_RECORD_SWITCH_CPU_WIDE OUT preempt  next pid/tid: 11019/11019
            forkit 11019 [001] 66663.271500523: PERF_RECORD_SWITCH_CPU_WIDE IN           prev pid/tid: 11020/11020
            forkit 11019 [001] 66663.271517241:          1 instructions:k:  ffffffffb24012cd error_entry+0x6d ([kernel.kallsyms])
            forkit 11019 [001] 66663.271664080: PERF_RECORD_EXIT(11019:11019):(1386:1386)
            forkit 11019 [001] 66663.271688752: PERF_RECORD_SWITCH_CPU_WIDE OUT          next pid/tid:    -1/-1
               :-1    -1 [001] 66663.271692086: PERF_RECORD_SWITCH_CPU_WIDE IN           prev pid/tid: 11019/11019
                :-1    -1 [001] 66663.271707466:          1 instructions:k:  ffffffffb18eb096 update_load_avg+0x306 ([kernel.kallsyms])

Fixes: 86c2786994bd7c ("perf intel-pt: Add support for PERF_RECORD_SWITCH")
Signed-off-by: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Yu-cheng Yu &lt;yu-cheng.yu@intel.com&gt;
Link: http://lore.kernel.org/lkml/20200909084923.9096-3-adrian.hunter@intel.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>ida: Free allocated bitmap in error path</title>
<updated>2020-10-29T08:57:47+00:00</updated>
<author>
<name>Matthew Wilcox (Oracle)</name>
<email>willy@infradead.org</email>
</author>
<published>2020-04-02T18:26:13+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=2577720d35e26b92f30eed4b17565f24b3c661d8'/>
<id>2577720d35e26b92f30eed4b17565f24b3c661d8</id>
<content type='text'>
[ Upstream commit a219b856a2b993da234108307be772448f22b0ce ]

If a bitmap needs to be allocated, and then by the time the thread
is scheduled to be run again all the indices which would satisfy the
allocation have been allocated then we would leak the allocation.  Almost
impossible to hit in practice, but a trivial fix.  Found by Coverity.

Fixes: f32f004cddf8 ("ida: Convert to XArray")
Reported-by: coverity-bot &lt;keescook+coverity-bot@chromium.org&gt;
Reviewed-by: Kees Cook &lt;keescook@chromium.org&gt;
Signed-off-by: Matthew Wilcox (Oracle) &lt;willy@infradead.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 a219b856a2b993da234108307be772448f22b0ce ]

If a bitmap needs to be allocated, and then by the time the thread
is scheduled to be run again all the indices which would satisfy the
allocation have been allocated then we would leak the allocation.  Almost
impossible to hit in practice, but a trivial fix.  Found by Coverity.

Fixes: f32f004cddf8 ("ida: Convert to XArray")
Reported-by: coverity-bot &lt;keescook+coverity-bot@chromium.org&gt;
Reviewed-by: Kees Cook &lt;keescook@chromium.org&gt;
Signed-off-by: Matthew Wilcox (Oracle) &lt;willy@infradead.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>selftests/ftrace: Change synthetic event name for inter-event-combined test</title>
<updated>2020-10-29T08:57:45+00:00</updated>
<author>
<name>Tom Zanussi</name>
<email>zanussi@kernel.org</email>
</author>
<published>2020-10-13T14:17:56+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=e7f826cd20a684b75c8d035fe1fe2def731ee3e5'/>
<id>e7f826cd20a684b75c8d035fe1fe2def731ee3e5</id>
<content type='text'>
[ Upstream commit 96378b2088faea68f1fb05ea6b9a566fc569a44c ]

This test uses waking+wakeup_latency as an event name, which doesn't
make sense since it includes an operator.  Illegal names are now
detected by the synthetic event command parsing, which causes this
test to fail.  Change the name to 'waking_plus_wakeup_latency' to
prevent this.

Link: https://lkml.kernel.org/r/a1ee2f76ff28ef7166fb788ca8be968887808920.1602598160.git.zanussi@kernel.org

Fixes: f06eec4d0f2c (selftests: ftrace: Add inter-event hist triggers testcases)
Acked-by: Masami Hiramatsu &lt;mhiramat@kernel.org&gt;
Tested-by: Masami Hiramatsu &lt;mhiramat@kernel.org&gt;
Signed-off-by: Tom Zanussi &lt;zanussi@kernel.org&gt;
Signed-off-by: Steven Rostedt (VMware) &lt;rostedt@goodmis.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 96378b2088faea68f1fb05ea6b9a566fc569a44c ]

This test uses waking+wakeup_latency as an event name, which doesn't
make sense since it includes an operator.  Illegal names are now
detected by the synthetic event command parsing, which causes this
test to fail.  Change the name to 'waking_plus_wakeup_latency' to
prevent this.

Link: https://lkml.kernel.org/r/a1ee2f76ff28ef7166fb788ca8be968887808920.1602598160.git.zanussi@kernel.org

Fixes: f06eec4d0f2c (selftests: ftrace: Add inter-event hist triggers testcases)
Acked-by: Masami Hiramatsu &lt;mhiramat@kernel.org&gt;
Tested-by: Masami Hiramatsu &lt;mhiramat@kernel.org&gt;
Signed-off-by: Tom Zanussi &lt;zanussi@kernel.org&gt;
Signed-off-by: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>selftests: rtnetlink: load fou module for kci_test_encap_fou() test</title>
<updated>2020-10-29T08:57:27+00:00</updated>
<author>
<name>Po-Hsu Lin</name>
<email>po-hsu.lin@canonical.com</email>
</author>
<published>2020-10-19T03:09:28+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=c5e4e010f39e4984045c270b42d065d1cfdaacb4'/>
<id>c5e4e010f39e4984045c270b42d065d1cfdaacb4</id>
<content type='text'>
[ Upstream commit 26ebd6fed9bb3aa480c7c0f147ac0e7b11000f65 ]

The kci_test_encap_fou() test from kci_test_encap() in rtnetlink.sh
needs the fou module to work. Otherwise it will fail with:

  $ ip netns exec "$testns" ip fou add port 7777 ipproto 47
  RTNETLINK answers: No such file or directory
  Error talking to the kernel

Add the CONFIG_NET_FOU into the config file as well. Which needs at
least to be set as a loadable module.

Fixes: 6227efc1a20b ("selftests: rtnetlink.sh: add vxlan and fou test cases")
Signed-off-by: Po-Hsu Lin &lt;po-hsu.lin@canonical.com&gt;
Link: https://lore.kernel.org/r/20201019030928.9859-1-po-hsu.lin@canonical.com
Signed-off-by: Jakub Kicinski &lt;kuba@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 26ebd6fed9bb3aa480c7c0f147ac0e7b11000f65 ]

The kci_test_encap_fou() test from kci_test_encap() in rtnetlink.sh
needs the fou module to work. Otherwise it will fail with:

  $ ip netns exec "$testns" ip fou add port 7777 ipproto 47
  RTNETLINK answers: No such file or directory
  Error talking to the kernel

Add the CONFIG_NET_FOU into the config file as well. Which needs at
least to be set as a loadable module.

Fixes: 6227efc1a20b ("selftests: rtnetlink.sh: add vxlan and fou test cases")
Signed-off-by: Po-Hsu Lin &lt;po-hsu.lin@canonical.com&gt;
Link: https://lore.kernel.org/r/20201019030928.9859-1-po-hsu.lin@canonical.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>selftests: forwarding: Add missing 'rp_filter' configuration</title>
<updated>2020-10-29T08:57:27+00:00</updated>
<author>
<name>Ido Schimmel</name>
<email>idosch@nvidia.com</email>
</author>
<published>2020-10-15T08:45:25+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=6f7c40767bf4c2a44d61d24720a0f0f02624979d'/>
<id>6f7c40767bf4c2a44d61d24720a0f0f02624979d</id>
<content type='text'>
[ Upstream commit 71a0e29e99405d89b695882d52eec60844173697 ]

When 'rp_filter' is configured in strict mode (1) the tests fail because
packets received from the macvlan netdevs would not be forwarded through
them on the reverse path.

Fix this by disabling the 'rp_filter', meaning no source validation is
performed.

Fixes: 1538812e0880 ("selftests: forwarding: Add a test for VXLAN asymmetric routing")
Fixes: 438a4f5665b2 ("selftests: forwarding: Add a test for VXLAN symmetric routing")
Signed-off-by: Ido Schimmel &lt;idosch@nvidia.com&gt;
Reported-by: Hangbin Liu &lt;liuhangbin@gmail.com&gt;
Tested-by: Hangbin Liu &lt;liuhangbin@gmail.com&gt;
Link: https://lore.kernel.org/r/20201015084525.135121-1-idosch@idosch.org
Signed-off-by: Jakub Kicinski &lt;kuba@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 71a0e29e99405d89b695882d52eec60844173697 ]

When 'rp_filter' is configured in strict mode (1) the tests fail because
packets received from the macvlan netdevs would not be forwarded through
them on the reverse path.

Fix this by disabling the 'rp_filter', meaning no source validation is
performed.

Fixes: 1538812e0880 ("selftests: forwarding: Add a test for VXLAN asymmetric routing")
Fixes: 438a4f5665b2 ("selftests: forwarding: Add a test for VXLAN symmetric routing")
Signed-off-by: Ido Schimmel &lt;idosch@nvidia.com&gt;
Reported-by: Hangbin Liu &lt;liuhangbin@gmail.com&gt;
Tested-by: Hangbin Liu &lt;liuhangbin@gmail.com&gt;
Link: https://lore.kernel.org/r/20201015084525.135121-1-idosch@idosch.org
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf cs-etm: Move definition of 'traceid_list' global variable from header file</title>
<updated>2020-10-17T08:11:21+00:00</updated>
<author>
<name>Leo Yan</name>
<email>leo.yan@linaro.org</email>
</author>
<published>2020-05-05T13:36:42+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=bc79abf4afea97d5ce682aa2bd1095fb74400916'/>
<id>bc79abf4afea97d5ce682aa2bd1095fb74400916</id>
<content type='text'>
commit 168200b6d6ea0cb5765943ec5da5b8149701f36a upstream.

The variable 'traceid_list' is defined in the header file cs-etm.h,
if multiple C files include cs-etm.h the compiler might complaint for
multiple definition of 'traceid_list'.

To fix multiple definition error, move the definition of 'traceid_list'
into cs-etm.c.

Fixes: cd8bfd8c973e ("perf tools: Add processing of coresight metadata")
Reported-by: Thomas Backlund &lt;tmb@mageia.org&gt;
Signed-off-by: Leo Yan &lt;leo.yan@linaro.org&gt;
Reviewed-by: Mathieu Poirier &lt;mathieu.poirier@linaro.org&gt;
Reviewed-by: Mike Leach &lt;mike.leach@linaro.org&gt;
Tested-by: Mike Leach &lt;mike.leach@linaro.org&gt;
Tested-by: Thomas Backlund &lt;tmb@mageia.org&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.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: Suzuki Poulouse &lt;suzuki.poulose@arm.com&gt;
Cc: Tor Jeremiassen &lt;tor@ti.com&gt;
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lore.kernel.org/lkml/20200505133642.4756-1-leo.yan@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Cc: Paul Barker &lt;pbarker@konsulko.com&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>
commit 168200b6d6ea0cb5765943ec5da5b8149701f36a upstream.

The variable 'traceid_list' is defined in the header file cs-etm.h,
if multiple C files include cs-etm.h the compiler might complaint for
multiple definition of 'traceid_list'.

To fix multiple definition error, move the definition of 'traceid_list'
into cs-etm.c.

Fixes: cd8bfd8c973e ("perf tools: Add processing of coresight metadata")
Reported-by: Thomas Backlund &lt;tmb@mageia.org&gt;
Signed-off-by: Leo Yan &lt;leo.yan@linaro.org&gt;
Reviewed-by: Mathieu Poirier &lt;mathieu.poirier@linaro.org&gt;
Reviewed-by: Mike Leach &lt;mike.leach@linaro.org&gt;
Tested-by: Mike Leach &lt;mike.leach@linaro.org&gt;
Tested-by: Thomas Backlund &lt;tmb@mageia.org&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.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: Suzuki Poulouse &lt;suzuki.poulose@arm.com&gt;
Cc: Tor Jeremiassen &lt;tor@ti.com&gt;
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lore.kernel.org/lkml/20200505133642.4756-1-leo.yan@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Cc: Paul Barker &lt;pbarker@konsulko.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>perf top: Fix stdio interface input handling with glibc 2.28+</title>
<updated>2020-10-14T08:32:59+00:00</updated>
<author>
<name>Tommi Rantala</name>
<email>tommi.t.rantala@nokia.com</email>
</author>
<published>2020-03-05T08:37:12+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=2118c7ba5f2a08df126d59006e2cf8f7cd68aecb'/>
<id>2118c7ba5f2a08df126d59006e2cf8f7cd68aecb</id>
<content type='text'>
commit 29b4f5f188571c112713c35cc87eefb46efee612 upstream.

Since glibc 2.28 when running 'perf top --stdio', input handling no
longer works, but hitting any key always just prints the "Mapped keys"
help text.

To fix it, call clearerr() in the display_thread() loop to clear any EOF
sticky errors, as instructed in the glibc NEWS file
(https://sourceware.org/git/?p=glibc.git;a=blob;f=NEWS):

 * All stdio functions now treat end-of-file as a sticky condition.  If you
   read from a file until EOF, and then the file is enlarged by another
   process, you must call clearerr or another function with the same effect
   (e.g. fseek, rewind) before you can read the additional data.  This
   corrects a longstanding C99 conformance bug.  It is most likely to affect
   programs that use stdio to read interactive input from a terminal.
   (Bug #1190.)

Signed-off-by: Tommi Rantala &lt;tommi.t.rantala@nokia.com&gt;
Tested-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.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;
Link: http://lore.kernel.org/lkml/20200305083714.9381-2-tommi.t.rantala@nokia.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

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commit 29b4f5f188571c112713c35cc87eefb46efee612 upstream.

Since glibc 2.28 when running 'perf top --stdio', input handling no
longer works, but hitting any key always just prints the "Mapped keys"
help text.

To fix it, call clearerr() in the display_thread() loop to clear any EOF
sticky errors, as instructed in the glibc NEWS file
(https://sourceware.org/git/?p=glibc.git;a=blob;f=NEWS):

 * All stdio functions now treat end-of-file as a sticky condition.  If you
   read from a file until EOF, and then the file is enlarged by another
   process, you must call clearerr or another function with the same effect
   (e.g. fseek, rewind) before you can read the additional data.  This
   corrects a longstanding C99 conformance bug.  It is most likely to affect
   programs that use stdio to read interactive input from a terminal.
   (Bug #1190.)

Signed-off-by: Tommi Rantala &lt;tommi.t.rantala@nokia.com&gt;
Tested-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.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;
Link: http://lore.kernel.org/lkml/20200305083714.9381-2-tommi.t.rantala@nokia.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

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