From a6763625ae6f8aa5ee82fcd8fa4e5e38db20dbc6 Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Thu, 12 Mar 2020 13:56:37 +0300 Subject: [PATCH] perf/core: Fix reversed NULL check in perf_event_groups_less() This NULL check is reversed so it leads to a Smatch warning and presumably a NULL dereference. kernel/events/core.c:1598 perf_event_groups_less() error: we previously assumed 'right->cgrp->css.cgroup' could be null (see line 1590) Fixes: 95ed6c707f26 ("perf/cgroup: Order events in RB tree by cgroup id") Signed-off-by: Dan Carpenter Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20200312105637.GA8960@mwanda --- kernel/events/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index b5a68d26f0b9..d22e4ba59dfa 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -1586,7 +1586,7 @@ perf_event_groups_less(struct perf_event *left, struct perf_event *right) */ return true; } - if (!right->cgrp || right->cgrp->css.cgroup) { + if (!right->cgrp || !right->cgrp->css.cgroup) { /* * Right has no cgroup but left does, no cgroups come * first.