From: Jiri Olsa <jolsa@kernel.org>
Date: Mon, 2 Jun 2014 17:44:23 +0000 (-0400)
Subject: perf record: Fix poll return value propagation
X-Git-Tag: omap-for-v3.16/fixes-against-rc1~34^2~15^2~1
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a515114fa3cff8f1da10cd68914d55c10879c3e0;p=pandora-kernel.git

perf record: Fix poll return value propagation

If the perf record command is interrupted in record__mmap_read_all
function, the 'done' is set and err has the latest poll return
value, which is most likely positive number (= number of pollfds
ready to read).

This 'positive err' is then propagated to the exit code, resulting
in not finishing the perf.data header properly, causing following
error in report:

  # perf record -F 50000 -a

  ---
  make the system real busy, so there's more chance
  to interrupt perf in event writing code
  ---

  ^C[ perf record: Woken up 16 times to write data ]
  [ perf record: Captured and wrote 30.292 MB perf.data (~1323468 samples) ]

  # perf report --stdio > /dev/null
  WARNING: The perf.data file's data size field is 0 which is unexpected.
  Was the 'perf record' command properly terminated?

Fixing this by checking for positive poll return value
and setting err to 0.

Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1401732126-19465-1-git-send-email-jolsa@kernel.org
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---

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