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From: Arnaldo Carvalho de Melo <acme@kernel.org>
To: Ingo Molnar <mingo@kernel.org>
Cc: linux-kernel@vger.kernel.org,
	Vineet Gupta <Vineet.Gupta1@synopsys.com>,
	Vineet Gupta <vgupta@synopsys.com>,
	Alexey Brodkin <Alexey.Brodkin@synopsys.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Arnaldo Carvalho de Melo <acme@redhat.com>
Subject: [PATCH 01/10] perf evsel: Don't rely on malloc working for sz 0
Date: Thu, 29 Jan 2015 17:23:36 -0300	[thread overview]
Message-ID: <1422563025-28402-2-git-send-email-acme@kernel.org> (raw)
In-Reply-To: <1422563025-28402-1-git-send-email-acme@kernel.org>

From: Vineet Gupta <Vineet.Gupta1@synopsys.com>

When running perf on ARC (uClibc based userspace), ran into this issue
   ------------->8----------------
	[ARCLinux]$ ./perf record ls
	bin             etc             perf            sys
	debug           init            perf.data       tmp
	[ perf record: Woken up 1 times to write data ]
	[ perf record: Captured and wrote 0.001 MB perf.data (~24 samples) ]

	[ARCLinux]$ ./perf report
	incompatible file format (rerun with -v to learn more)
   ------------->8----------------

The problem happens in the following call stack when zalloc is called
with size zero

glibc default / uClibc with MALLOC_GLIBC_COMPAT are OK, but not if that
config option is not enabled.

  cmd_report
     perf_session__new
	perf_session__open
	    perf_session__read_header
		read_attr(fd, header, &f_attr)
		nr_ids = f_attr.ids.size / sizeof(u64); <-- 0
		perf_evsel__alloc_id(vsel, 1, nr_ids)
			zalloc(ncpus * nthreads * sizeof(u64)) <-- 0

header.c: read_attr()

(gdb) p *f_attr
$17 = {
  attr = {
    type = 0,
    size = 96,
    config = 0,
    {
      sample_period = 4000,
      sample_freq = 4000
    },
...
  ids = {
    offset = 104,
    size = 0      <------
  }
}

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Suggested-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexey Brodkin <Alexey.Brodkin@synopsys.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1421156604-30603-5-git-send-email-vgupta@synopsys.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/evsel.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 1e90c8557ede..1d826d63bc20 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -797,6 +797,9 @@ int perf_evsel__enable(struct perf_evsel *evsel, int ncpus, int nthreads)
 
 int perf_evsel__alloc_id(struct perf_evsel *evsel, int ncpus, int nthreads)
 {
+	if (ncpus == 0 || nthreads == 0)
+		return 0;
+
 	if (evsel->system_wide)
 		nthreads = 1;
 
-- 
1.9.3


  reply	other threads:[~2015-01-29 20:23 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-01-29 20:23 [GIT PULL 00/10] perf/core improvements and fixes Arnaldo Carvalho de Melo
2015-01-29 20:23 ` Arnaldo Carvalho de Melo [this message]
2015-01-29 20:23 ` [PATCH 02/10] perf tools: Provide stub for missing pthread_attr_setaffinity_np Arnaldo Carvalho de Melo
2015-01-29 20:23 ` [PATCH 03/10] perf callchain: Cache eh/debug frame offset for dwarf unwind Arnaldo Carvalho de Melo
2015-01-29 20:23 ` [PATCH 04/10] perf tools: Do not use __perf_session__process_events() directly Arnaldo Carvalho de Melo
2015-01-29 20:23 ` [PATCH 05/10] perf record: Show precise number of samples Arnaldo Carvalho de Melo
2015-01-29 20:23 ` [PATCH 06/10] perf header: Set header version correctly Arnaldo Carvalho de Melo
2015-01-29 20:23 ` [PATCH 07/10] perf evsel: Set attr.task bit for a tracking event Arnaldo Carvalho de Melo
2015-01-29 20:23 ` [PATCH 08/10] perf symbols: Support to read compressed module from build-id cache Arnaldo Carvalho de Melo
2015-01-29 20:23 ` [PATCH 09/10] perf tools: Use perf_data_file__fd() consistently Arnaldo Carvalho de Melo
2015-01-29 20:23 ` [PATCH 10/10] perf symbols: Convert lseek + read to pread Arnaldo Carvalho de Melo
2015-01-30 18:28 ` [GIT PULL 00/10] perf/core improvements and fixes Ingo Molnar

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