4.9-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 @@ -129,14 +129,8 @@ int get_callchain_buffers(int event_max_ 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);
