linux-kernel - [PATCH 1/2] perf script: Fix brstackinsn for AUXTRACE

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Date:   Wed, 27 Nov 2019 11:53:21 +0200
From:   Adrian Hunter <adrian.hunter@...el.com>
To:     Arnaldo Carvalho de Melo <acme@...nel.org>
Cc:     Jiri Olsa <jolsa@...hat.com>, linux-kernel@...r.kernel.org,
        Andi Kleen <ak@...ux.intel.com>
Subject: [PATCH 1/2] perf script: Fix brstackinsn for AUXTRACE

brstackinsn must be allowed to be set by the user when AUX area data has
been captured because, in that case, the branch stack might be
synthesized on the fly. This fixes the following error:

Before:

  $ perf record -e '{intel_pt//,cpu/mem_inst_retired.all_loads,aux-sample-size=8192/pp}:u' grep -rqs jhgjhg /boot
  [ perf record: Woken up 19 times to write data ]
  [ perf record: Captured and wrote 2.274 MB perf.data ]
  $ perf script -F +brstackinsn --xed --itrace=i1usl100 | head
  Display of branch stack assembler requested, but non all-branch filter set
  Hint: run 'perf record -b ...'

After:

  $ perf record -e '{intel_pt//,cpu/mem_inst_retired.all_loads,aux-sample-size=8192/pp}:u' grep -rqs jhgjhg /boot
  [ perf record: Woken up 19 times to write data ]
  [ perf record: Captured and wrote 2.274 MB perf.data ]
  $ perf script -F +brstackinsn --xed --itrace=i1usl100 | head
            grep 13759 [002]  8091.310257:       1862                                        instructions:uH:      5641d58069eb bmexec+0x86b (/bin/grep)
        bmexec+2485:
        00005641d5806b35                        jnz 0x5641d5806bd0              # MISPRED
        00005641d5806bd0                        movzxb  (%r13,%rdx,1), %eax
        00005641d5806bd6                        add %rdi, %rax
        00005641d5806bd9                        movzxb  -0x1(%rax), %edx
        00005641d5806bdd                        cmp %rax, %r14
        00005641d5806be0                        jnb 0x5641d58069c0              # MISPRED
        mismatch of LBR data and executable
        00005641d58069c0                        movzxb  (%r13,%rdx,1), %edi

Reported-by: Andi Kleen <ak@...ux.intel.com>
Fixes: 48d02a1d5c13 ("perf script: Add 'brstackinsn' for branch stacks")
Signed-off-by: Adrian Hunter <adrian.hunter@...el.com>
---
 tools/perf/builtin-script.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
index 7b2f0922050c..e8db26b9b29e 100644
--- a/tools/perf/builtin-script.c
+++ b/tools/perf/builtin-script.c
@@ -448,7 +448,7 @@ static int perf_evsel__check_attr(struct evsel *evsel,
 		       "selected. Hence, no address to lookup the source line number.\n");
 		return -EINVAL;
 	}
-	if (PRINT_FIELD(BRSTACKINSN) &&
+	if (PRINT_FIELD(BRSTACKINSN) && !allow_user_set &&
 	    !(perf_evlist__combined_branch_type(session->evlist) &
 	      PERF_SAMPLE_BRANCH_ANY)) {
 		pr_err("Display of branch stack assembler requested, but non all-branch filter set\n"
-- 
2.17.1