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d="scan'208";a="81859536" Received: from mail-lf1-f69.google.com ([209.85.167.69]) by smtpmx5.ucr.edu with ESMTP/TLS/ECDHE-RSA-AES128-GCM-SHA256; 09 Oct 2019 21:56:31 -0700 Received: by mail-lf1-f69.google.com with SMTP id c13so1042831lfk.23 for ; Wed, 09 Oct 2019 21:56:31 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:from:date:message-id:subject:to; bh=qNxdxggCQd3xr6rdB50E8SDcymvAFEfwkLrZ0yN0AVk=; b=b6M1Pgc5muPkYWLPgT9EjysinIqXHORN1q12JGc9+5wY1fa5YFgynFQ4DCW7tq5qQF IffH+0E0rGZd3k5jaI6MXWxeu6c5zt/wdaW4tJFJFiGjiYpfmzXRpelXmqGA+U5NHB6o kUtGiTT2IV3UR0lgLhvnhQuLbHx1bMs84fmS6V77X6aItchyfnQo3X1YLu2wwMJj8yW6 43irrpEKZzrKHRRJ44iO85iaBjr+svAnf/ixEVv1Ky/91UHdpcMvsttRlOulv/cYY3T4 kq+OSM5fzQD9efOqHP/0qE5MoiNEgYvTbbCOuScnIMkqgvW2MoUp0RU3wsirCKxumrc5 iayA== X-Gm-Message-State: APjAAAWjdNk8QYzgjmYkEBjiaychZs5P8urQdvaR9ilE0QEPPEXoTt21 A3qfLKeeSKYHMw1WdnEKQirP78aVxLKSkd8MCE2SnEnJrUyBcR9KN2DShah0w1KQg7jF5EPWdr1 KB+jNb3iO2FzPioYOo0Y0dU6mpwn+ X-Received: by 2002:a2e:8315:: with SMTP id a21mr4754257ljh.133.1570683390112; Wed, 09 Oct 2019 21:56:30 -0700 (PDT) X-Google-Smtp-Source: APXvYqy074NwSC68d15vpYDMj4CmQOd5kqAOtBUwTFkuYJ5w5L2OC3C3LTQnOPqg+KMLwvdE5weYDp2K5PS//xB4CKM= X-Received: by 2002:a2e:8315:: with SMTP id a21mr4754231ljh.133.1570683389789; Wed, 09 Oct 2019 21:56:29 -0700 (PDT) MIME-Version: 1.0 From: Yizhuo Zhai Date: Wed, 9 Oct 2019 21:56:04 -0700 Message-ID: Subject: Potential NULL pointer deference in mm/memcontrol.c To: Johannes Weiner , Michal Hocko , Vladimir Davydov , cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Zhiyun Qian , Chengyu Song Content-Type: text/plain; charset="UTF-8" X-Bogosity: Ham, tests=bogofilter, spamicity=0.189163, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Hi All: mm/memcontrol.c: The function mem_cgroup_from_css() could return NULL, but some callers in this file checks the return value but directly dereference it, which seems potentially unsafe. Such callers include mem_cgroup_hierarchy_read(), mem_cgroup_hierarchy_write(), mem_cgroup_read_u64(), mem_cgroup_reset(), etc. -- Kind Regards, Yizhuo Zhai Computer Science, Graduate Student University of California, Riverside