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charset="us-ascii" Content-ID: <45474FB10F28AD468D4F949947B3B6FB@namprd15.prod.outlook.com> Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-MS-Exchange-CrossTenant-Network-Message-Id: bd9203ef-8253-4d50-bfc2-08d6e9d93499 X-MS-Exchange-CrossTenant-originalarrivaltime: 05 Jun 2019 17:14:02.2198 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 8ae927fe-1255-47a7-a2af-5f3a069daaa2 X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: guro@fb.com X-MS-Exchange-Transport-CrossTenantHeadersStamped: BYAPR15MB2742 X-OriginatorOrg: fb.com X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-06-05_10:,, signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1906050107 X-FB-Internal: deliver X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, Jun 04, 2019 at 09:35:02PM -0700, Shakeel Butt wrote: > On Tue, Jun 4, 2019 at 7:45 PM Roman Gushchin wrote: > > > > Johannes noticed that reading the memcg kmem_cache pointer in > > cache_from_memcg_idx() is performed using READ_ONCE() macro, > > which doesn't implement a SMP barrier, which is required > > by the logic. > > > > Add a proper smp_rmb() to be paired with smp_wmb() in > > memcg_create_kmem_cache(). > > > > The same applies to memcg_create_kmem_cache() itself, > > which reads the same value without barriers and READ_ONCE(). > > > > Suggested-by: Johannes Weiner > > Signed-off-by: Roman Gushchin >=20 > Reviewed-by: Shakeel Butt >=20 > This seems like independent to the series. Shouldn't this be Cc'ed stable= ? It is independent, but let's keep it here to avoid merge conflicts. It has been so for a long time, and nobody complained, so I'm not sure if we really need a stable backport. Do you have a different opinion? Thank you!