From: Adrian Hunter <adrian.hunter@intel.com>
To: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>,
linux-kernel@vger.kernel.org, Andi Kleen <ak@linux.intel.com>
Subject: [PATCH 2/2] perf script: Fix invalid LBR/binary mismatch error
Date: Wed, 27 Nov 2019 11:56:31 +0200 [thread overview]
Message-ID: <20191127095631.15663-1-adrian.hunter@intel.com> (raw)
The 'len' returned by grab_bb() includes an extra MAXINSN bytes to allow
for the last instruction, so the the final 'offs' will not be 'len'.
Fix the error condition logic accordingly.
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
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
After:
$ 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
00005641d58069c0 movzxb (%r13,%rdx,1), %edi
00005641d58069c6 add %rax, %rdi
Reported-by: Andi Kleen <ak@linux.intel.com>
Fixes: e98df280bc2a ("perf script brstackinsn: Fix recovery from LBR/binary mismatch")
Signed-off-by: Adrian Hunter <adrian.hunter@intel.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 e8db26b9b29e..e2406b291c1c 100644
--- a/tools/perf/builtin-script.c
+++ b/tools/perf/builtin-script.c
@@ -1126,7 +1126,7 @@ static int perf_sample__fprintf_brstackinsn(struct perf_sample *sample,
insn++;
}
}
- if (off != (unsigned)len)
+ if (off != end - start)
printed += fprintf(fp, "\tmismatch of LBR data and executable\n");
}
--
2.17.1
next reply other threads:[~2019-11-27 9:57 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-27 9:56 Adrian Hunter [this message]
2019-11-27 15:18 ` [PATCH 2/2] perf script: Fix invalid LBR/binary mismatch error Arnaldo Carvalho de Melo
2019-11-29 6:02 ` [tip: perf/urgent] " tip-bot2 for Adrian Hunter
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