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Tue, 13 Dec 2022 13:44:58 -0500 X-MC-Unique: BvYR3lxsNKWZAZOxPDL65Q-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.rdu2.redhat.com [10.11.54.8]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id E6381185A78F; Tue, 13 Dec 2022 18:44:57 +0000 (UTC) Received: from llong.com (unknown [10.22.32.205]) by smtp.corp.redhat.com (Postfix) with ESMTP id 2E9CCC15BA0; Tue, 13 Dec 2022 18:44:57 +0000 (UTC) From: Waiman Long To: Jens Axboe , Tejun Heo , Josef Bacik , Zefan Li , Johannes Weiner , Andrew Morton Cc: cgroups@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, =?UTF-8?q?Michal=20Koutn=C3=BD?= , "Dennis Zhou (Facebook)" , Waiman Long Subject: [PATCH-block v3 0/2] blk-cgroup: Fix potential UAF & flush rstat at blkgs destruction path Date: Tue, 13 Dec 2022 13:44:44 -0500 Message-Id: <20221213184446.50181-1-longman@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.1 on 10.11.54.8 X-Rspamd-Queue-Id: A0FA5C0008 X-Stat-Signature: jzpdco8kb7z7k5d54k4urcmm9d3hk8jw X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1670957104-41903 X-HE-Meta: U2FsdGVkX1/EpQGsP+KCnYfyv2vFAHMb2l/aMG+Sm71msrlQi1HNK7ixhj9evGGSqSOwEhO/kCndyfSDMXQ6JCDZyi7HYJcBpFaMkiWVc2XRqSIcTuGjYzvSaG4brUWr3KtyWpeF1KDpsc3CLBXbz8NBb+tP1GtiJu9LeF4PMkWVVNTvNIv26/UTkjQwJ8Pk73vIo/k6OREWyP/fNBcpzAiQK1gDIzJxyrMmC7FvU/JxjgmOy8D71zPpfFnE3+5KZ2Om9za/M1is+ESYm019ua/VAyuer2nLpEs22t61XMPJm7F3SQ7OT8GYCvQJ8TBMvT7UjzbHYV9k8rHQYixWi3I5oFyeHpohwZsyq5lKniPSBxLZ7VFvpRIBrBq9r6Qxp9PijHHmRaFc/VYCFgTln/bw8joNP9gK3LMaBAJeIGFo02/djZ/ltY1RASNKhNdYgusgdsgCuczyWgiMYbPifcPD28kSqJVz1mZu4nOzGoQbQ5w9/iZhQkwqbQPYelsbPUStjZK/iH3f3DMlfuT0Gj3PEp3Mf1Mn7Ij5xBipjqp4yVlTUcJsZSf6AwVl3t9CS4sxnBNVe4Y5M8y4Mjf219aGEDUREupQBU9JMxQN6B+PbqVuRF3FqzDRf/7Soy+rp4PHURCToLmsFXM1FLZH2RKJLK0SChrIR4Qz5c7jnUmkGE/XOcfR1LxkO2XsJCEp6gsxzbDZ2zgkgxpjYIgfpU6g7wpNDFcmp6Qy3PQj2JBiwRnXWSAW3Vb+JJgNYq3F4vvTvNcjf5k8XrOREr4B3tCve43ihvFERMmM8ZddmzJRCHlbNHyPApY6IxrPbrIDcfp6PpjXEhR9t3iaOjY+odLnIAyPtl1cXVYTA03+aRNrDlXJQ8XsxQ8cLRyJJeEn 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: v3: - Drop v2 patch 2 as it may not be needed. - Replace css_tryget() with percpu_ref_is_zero() in patch 1 as suggested by Tejun. - Expand comment on patch 2 to elaborate the reason for this patch. v2: - Remove unnecessary rcu_read_{lock|unlock} from cgroup_rstat_css_cpu_flush() in patch 3. It was found that blkcg_destroy_blkgs() may be called with all blkcg references gone. This may potentially cause user-after-free and so should be fixed. The second patch flushes rstat when blkcg_destroy_blkgs(). Waiman Long (2): bdi, blk-cgroup: Fix potential UAF of blkcg blk-cgroup: Flush stats at blkgs destruction path block/blk-cgroup.c | 22 ++++++++++++++++++++++ include/linux/cgroup.h | 1 + kernel/cgroup/rstat.c | 18 ++++++++++++++++++ mm/backing-dev.c | 8 ++++++-- 4 files changed, 47 insertions(+), 2 deletions(-) -- 2.31.1