From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ross Zwisler Subject: [PATCH] cgroup: Fix uninitialized variable warning Date: Wed, 23 Dec 2015 14:30:40 -0700 Message-ID: <1450906240-21821-1-git-send-email-ross.zwisler@linux.intel.com> Mime-Version: 1.0 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="utf-8" To: Linus Torvalds , Tejun Heo Cc: Ross Zwisler , Li Zefan , Daniel Wagner , Johannes Weiner , cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Dave Jones , kernel-team-b10kYP2dOMg@public.gmane.org, Aleksa Sarai , Michal Hocko , Ingo Molnar , Peter Zijlstra , Neil Horman Commit 1f7dd3e5a6e4 ("cgroup: fix handling of multi-destination migrati= on from subtree_control enabling") introduced the following compiler warni= ng: mm/memcontrol.c: In function =E2=80=98mem_cgroup_can_attach=E2=80=99: mm/memcontrol.c:4790:9: warning: =E2=80=98memcg=E2=80=99 may be used un= initialized in this function [-Wmaybe-uninitialized] mc.to =3D memcg; ^ =46ix this by initializing 'memcg' to NULL and then verifying that it i= s set to a value before dereferencing it. Signed-off-by: Ross Zwisler --- This issue is present in v4.4-rc5 and later. --- mm/memcontrol.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index e234c21..69a28b3 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -4782,7 +4782,7 @@ static void mem_cgroup_clear_mc(void) static int mem_cgroup_can_attach(struct cgroup_taskset *tset) { struct cgroup_subsys_state *css; - struct mem_cgroup *memcg; + struct mem_cgroup *memcg =3D NULL; struct mem_cgroup *from; struct task_struct *leader, *p; struct mm_struct *mm; @@ -4805,7 +4805,7 @@ static int mem_cgroup_can_attach(struct cgroup_ta= skset *tset) p =3D leader; memcg =3D mem_cgroup_from_css(css); } - if (!p) + if (!p || !memcg) return 0; =20 /* --=20 2.6.3