linux-kernel - [PATCH] Revert "perf machine: Fix paranoid check in machine__set_kernel

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Date:   Wed, 11 Apr 2018 18:07:52 -0500
From:   Kim Phillips <kim.phillips@....com>
To:     Arnaldo Carvalho de Melo <acme@...nel.org>
Cc:     Jiri Olsa <jolsa@...hat.com>, Namhyung Kim <namhyung@...nel.org>,
        Jiri Olsa <jolsa@...nel.org>,
        lkml <linux-kernel@...r.kernel.org>,
        Ingo Molnar <mingo@...nel.org>,
        David Ahern <dsahern@...il.com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Peter Zijlstra <a.p.zijlstra@...llo.nl>, <kernel-team@....com>
Subject: [PATCH] Revert
 "perf machine: Fix paranoid check in machine__set_kernel_mmap()"

perf test 1 is failing on an arm64 box (that has a kernel module
loaded fwiw).  Running bisect resulted in commit 1d12cec6ce99 "perf
machine: Fix paranoid check in machine__set_kernel_mmap()" being the
first bad commit.  Reverting it fixes symbol resolution:

 # ./perf.bad record true; ./perf.bad --no-pager report --stdio --quiet
 [ perf record: Woken up 1 times to write data ]
 [ perf record: Captured and wrote 0.001 MB perf.data (10 samples) ]
     64.34%  true     [unknown]         [k] 0xffff20000809ffb8
     32.12%  true     [unknown]         [k] 0xffff20000869f400
      3.24%  true     [unknown]         [k] 0xffff20000868d924
      0.28%  perf.ba  [unknown]         [k] 0xffff200008598b34
      0.03%  perf.ba  [unknown]         [k] 0xffff200008598a94

 # ./perf.good record true; ./perf.good --no-pager report --stdio --quiet
 [ perf record: Woken up 1 times to write data ]
 [ perf record: Captured and wrote 0.001 MB perf.data (9 samples) ]
     91.71%  true     [kernel.kallsyms]  [k] restore_nameidata
      7.60%  true     [kernel.kallsyms]  [k] perf_iterate_ctx.constprop.38
      0.69%  perf.go  [kernel.kallsyms]  [k] perf_event_exec

Cc: Arnaldo Carvalho de Melo <acme@...nel.org>
Cc: Namhyung Kim <namhyung@...nel.org>
Cc: Jiri Olsa <jolsa@...nel.org>
Cc: Ingo Molnar <mingo@...nel.org>
Cc: David Ahern <dsahern@...il.com>
Cc: Alexander Shishkin <alexander.shishkin@...ux.intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@...llo.nl>
Cc: <kernel-team@....com>
Fixes: 1d12cec6ce99 ("perf machine: Fix paranoid check in machine__set_kernel_mmap()")
Signed-off-by: Kim Phillips <kim.phillips@....com>
---
It's not clear to me what the specific intent of the original commit
was, thus the revert.

 tools/perf/util/machine.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index 2eca8478e24f..089399139778 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -1224,7 +1224,7 @@ static void machine__set_kernel_mmap(struct machine *machine,
 		 * Be a bit paranoid here, some perf.data file came with
 		 * a zero sized synthesized MMAP event for the kernel.
 		 */
-		if (start == 0 && end == 0)
+		if (machine->vmlinux_maps[i]->end == 0)
 			machine->vmlinux_maps[i]->end = ~0ULL;
 	}
 }
-- 
2.17.0