[PATCH 4.4 39/56] perf: Remove superfluous allocation error check

From: Greg Kroah-Hartman
Date: Mon May 14 2018 - 03:40:40 EST


4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Jiri Olsa <jolsa@xxxxxxxxxx>

commit bfb3d7b8b906b66551424d7636182126e1d134c8 upstream.

If the get_callchain_buffers fails to allocate the buffer it will
decrease the nr_callchain_events right away.

There's no point of checking the allocation error for
nr_callchain_events > 1. Removing that check.

Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Tested-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Andi Kleen <andi@xxxxxxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: syzkaller-bugs@xxxxxxxxxxxxxxxx
Cc: x86@xxxxxxxxxx
Link: http://lkml.kernel.org/r/20180415092352.12403-3-jolsa@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
kernel/events/callchain.c | 10 ++--------
1 file changed, 2 insertions(+), 8 deletions(-)

--- a/kernel/events/callchain.c
+++ b/kernel/events/callchain.c
@@ -107,14 +107,8 @@ int get_callchain_buffers(void)
goto exit;
}

- if (count > 1) {
- /* If the allocation failed, give up */
- if (!callchain_cpus_entries)
- err = -ENOMEM;
- goto exit;
- }
-
- err = alloc_callchain_buffers();
+ if (count == 1)
+ err = alloc_callchain_buffers();
exit:
if (err)
atomic_dec(&nr_callchain_events);