From: Ian Rogers <irogers@google.com> stable inclusion from stable-v5.10.85 commit 77d255d28b342bb45cbc18fc3ad577ef09f3af75 bugzilla: 186032 https://gitee.com/openeuler/kernel/issues/I4QVI4 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- commit 4ffbe87e2d5b53bcb0213d8650bbe70bf942de6a upstream. sysfs__read_int() returns 0 on success, and so the fast read path was always failing. Fixes: bb629484d924118e ("perf tools: Simplify checking if SMT is active.") Signed-off-by: Ian Rogers <irogers@google.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: John Garry <john.garry@huawei.com> Cc: Kajol Jain <kjain@linux.ibm.com> Cc: Kan Liang <kan.liang@linux.intel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Paul Clarke <pc@us.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lore.kernel.org/lkml/20211124001231.3277836-2-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Chen Jun <chenjun102@huawei.com> Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com> --- tools/perf/util/smt.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/perf/util/smt.c b/tools/perf/util/smt.c index 20bacd5972ad..34f1b1b1176c 100644 --- a/tools/perf/util/smt.c +++ b/tools/perf/util/smt.c @@ -15,7 +15,7 @@ int smt_on(void) if (cached) return cached_result; - if (sysfs__read_int("devices/system/cpu/smt/active", &cached_result) > 0) + if (sysfs__read_int("devices/system/cpu/smt/active", &cached_result) >= 0) goto done; ncpu = sysconf(_SC_NPROCESSORS_CONF); -- 2.20.1